RE: skinny power cords.
Jim, It seems that some of the offshore manufactured cords are molded from melted Hershey bars! I am always very careful who I buy my cords from. Scott Lacey -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Jim Eichner Sent: Thursday, October 25, 2001 3:40 PM Cc: emc-p...@majordomo.ieee.org Subject: RE: skinny power cords. Thanks Rich: I suspect you're right. Isn't that mechanism exactly what the tracking index tests are meant to address? I thought that any UL-approved wiring device like this would have a material that is designed to resist tracking, hence my speculation that contamination might be involved. I guess there are a few more comments to be made here... 1. From what I know, the tracking index tests are horribly non-repeatable and are therefore somewhat meaningless. 2. The standards for plug caps and for multi-taps may not refer to UL746 and may not have any of their own requirements for tracking index of insulation. 3. We could take this as evidence that even compliance with the tracking index requirements doesn't prevent carbonization of the material where there's a high temperature heat source involved. There are lots of people who unplug anything they are not actively using. I guess it's not such a paranoid practice! Regards, Jim Eichner, P.Eng. Manager, Engineering Services Xantrex Technology Inc. Mobile Power web: www.xantrex.com http://www.xantrex.com Any opinions expressed are those of my invisible friend, who really exists. Honest. -Original Message- From: Rich Nute [mailto:ri...@sdd.hp.com] Sent: Thursday, October 25, 2001 12:14 PM To: jim.eich...@xantrex.com Cc: emc-p...@majordomo.ieee.org Subject: Re: skinny power cords. Hi Jim: I'm curious: given that North American plug blades are 1/2 apart, there must have been substantial contamination to aid in 120Vac jumping that far (arcing). Did you identify any sort of contamination or moisture? I don't believe contamination is a significant factor in events such as this one. I believe such events start with a loose connection between the plug and the socket (or between the wire and the socket parts). A loose connection means that the contact area is relatively small. In turn, this means high current density at the point of contact. The smaller the contact area, the greater the resistance of the contact. The smaller the contact area, the greater the current density at the point of contact. These two factors contribute to heating of the two parts, the plug blade and the socket. Heating tends to reduce the springiness of the socket part, and of the connection between the supply wire and the socket (because they are thermally connected). The heating also tends to degrade the surface of the insulating material in which the conductors are mounted. Heating also enhances oxidation of the plating on the parts, which further increases the resistance of the connections. If the plug-connected appliance is ON, arcing can occur as the parts expand due to heating and make various intermittant connections. Arc temperatures are very high, and can burn the surface of nearby insulating materials via radiation. As the surface degrades, leakages occur across the surfaces. At this point, whether or not the appliance is on or even connected is not a factor. There is a current path between the two poles along the surface of the insulator. This can either be between the socket parts, or between the wired parts. The leakage current causes further heating and micro-arcs where the leakage path opens due to current density. The micro-arcs further damage the insulator until there is nearly continuous micro-arcing. I suggest this is the source of the noise. The heat from the micro- arcing and the resistance of the carbonized surface of the insulator eventually lead to ignition and flames. I admit that this is a hypothesis. I believe that the process is more-or-less correct, but the details may not be correct. Best regards, Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical
MIL-STD for crimped terminals on wires?
To the group, Hopefully someone can tell me number of the MIL-STD ocument for crimped connections on wires? Even better if they referenced the web site where the standard could be downloaded. Thanks in advance. Scott Lacey --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: skinny power cords.
Yes, This the reason that the arc fault interrupter was invented. New codes require it on bedroom circuits I understand. Regards, Lee Schmitz --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: NEC Question BUT REMEMBER OSHA
Scott: Very, very, likely.. Jack - Original Message - From: Scott Barrows sbarr...@curtis-straus.com To: Jacob Schanker schan...@frontiernet.net; PSTC emc-p...@majordomo.ieee.org Sent: Thursday, October 25, 2001 5:10 PM Subject: Re: NEC Question BUT REMEMBER OSHA | Jacob, | I would imagine that when the electrical inspector came in to review the electrical connections of that computerized, | T1 hooked up brand new home, there would be an issue that would relate to the NEC. | | Scott | | Jacob Schanker wrote: | | Rich: | | You are implying, but not stating, that NEC has the force of law | regarding the domestic environment. | | This differs with my understanding, or lack thereof. I have | always regarded the National Electric Code as a recommended set | of standards and practices which enabled localities to reference | NEC in their local building codes, rather than develop their own | from scratch. | | Perhaps you can expand on where the force of law applies to the | NEC with regard to portable, plug-in (not permanently wired) home | appliances and such? | | Jack | | Jacob Z. Schanker, P.E. | 65 Crandon Way | Rochester, NY 14618 | Phone: 716 442 3909 | Fax: 716 442 2182 | j.schan...@ieee.org | | - Original Message - | From: Rich Nute ri...@sdd.hp.com | To: gkerv...@eu-link.com | Cc: schan...@frontiernet.net; wo...@sensormatic.com; | emc-p...@majordomo.ieee.org; mi...@ucentric.com | Sent: Thursday, October 25, 2001 2:32 PM | Subject: Re: NEC Question BUT REMEMBER OSHA | | | | | | | | | Hi Gregg: | | | | | |Just to ensure that I have my understanding right - if the | equipment is used | |where OSHA applies then it must be approved by a third | party like UL | | | | Yes. More specifically: | | | |If... the product is used by an employee in the workplace... | | | |Then... the product must be certified by an NRTL, | |of which UL is one. | | | |If it is domestic then it does not (in most states. | | | | No and yes. | | | | No, OSHA rules do not apply to a domestic place. | | | | Yes, NEC rules apply to a domestic place and do | | require third-party safety certification. | | | | OSHA rules apply to the workplace, not to domestic places. | | So, domestic places are not required -by OSHA- to have | | NRTL-certified products. | | | | HOWEVER, the National Electrical Code applies everywhere, | | including domestic places. The NEC requires products, | | including domestic products, to be listed by a third- | | party engaged in the safety evaluation of products. | | | | The NEC does not specify the third-party. During the | | process of adoption of the NEC by various city, county, | | or state governments, the government agency decides | | which certification houses are acceptable to them. The | | acceptable certification houses are published locally. | | | | For a third-party certifier, this means the certifier | | must not only apply to OSHA for NRTL, but must also | | apply to every jurisdiction in the USA for acceptance | | under the NEC. | | | | Many, but not all NRTLs are also accepted by the various | | city, county, or state governments under the local version | | of the NEC. | | | | Likewise, there are some certifiers who are accepted by | | one or more governments under the NEC, but are not NRTLs. | | | | There are a few pockets where local governments do not | | require listing under the NEC. | | | | In summary: | | | | OSHA requires products used in the workplace to be | | certified by an NRTL. | | | | The NEC requires products used in an installation | | (including domestic places) to be certified by an | | organization designated by the local government | | agency charged with enforcing the NEC. | | | | These are independent functions. | | | | For all practical purposes, third-party safety certification | | is required throughout the USA. | | | | Enforcement of both OSHA and NEC for cord-connected products | | is spotty at best. | | | | Since virtually all products are NRTL-certified, OSHA spends | | its time addressing more immediate workplace safety issues. | | | | Since cord-connected products are installed AFTER the | | electrical installation is complete and approved, and since | | virtually all products are safety-certified, there is little | | or no enforcement of NEC-required certification. | | | |AND, does anyone have a list of States where certification | is mandated? | | | | I would be easier to come up with a list of where certification | | is NOT required! :-) It would be a one-page list of cities | | or counties which have very low population densities. | | | | | | Best regards, | | Rich | | | | | | | | | | | | | | | | --- | This message is from the IEEE EMC Society Product Safety | Technical Committee emc-pstc discussion list.
Re: skinny power cords.
It definitely was not supplied by the heater company. It was a high quality UL approved cord. It's just that this cord carbonized and burst into flame as the arc was existing. The flames did immediately extinguish when the arc was stopped by unplugging the cord which is good. But again, it was disturbing that the 15A breaker provided no protection. Anyway, it was a good lesson for this sleeping guy. Now I take electrical distribution inside my home much more seriously. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Dan Kwok dk...@intetron.com To: Robert Macy m...@california.com; emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, October 25, 2001 1:42 PM Subject: Re: skinny power cords. Hi Robert, Recently, I bought several similar heaters for my home. I recall reading in the operation instructions, explicit safety warnings against using extension cords with the heater. Was the extension cord supplied with the heater? - Dan Kwok, P.Eng. Principal Engineer Electromagnetic Compatibility Intetron Consulting, Inc. Ph (604) 432-9874 E-mail dk...@intetron.com Internet http://www.intetron.com - Original Message - From: Robert Macy m...@california.com To: Roman, Dan dan.ro...@intel.com; emc-p...@majordomo.ieee.org Sent: Thursday, October 25, 2001 8:49 AM Subject: Re: skinny power cords. Just have to jump in here with personal experience: In our bedroom we have a deLonghi radiator heater which uses an extension cord (high cost UL approved) heavy guage #12 wire to power it - when it's used. This extension cord plugs into a multi outlet adapter, also heavy duty UL approved. At the time of the incident there was no power being used from this outlet. I was in another room, my wife was sitting on the edge of the bed watching a news blurb on TV when she heard a funny sound, a scritch, scritch. She called to me to come listen. Scritch, scritch, scritch got louder. As I arrived, flames started lapping up the wall from the outlet while still making arcing sounds. The flames were less than 6 inches from curtains. I reached into all this and unplugged the extension cord which luckily stopped the fireworks display. Imagine, if we had not been there. Upon examination, it appeared that an arc had formed between the blades of the extension cord (remember no power at the time). That arc was not sufficient to drop the 15A breaker to the outlet, yet was sufficient to carbonize the UL approved material which further sustained the arc. I posted this to the newsgroup alt.home.repair where a fireman jumped in describing how this exact mechanism is what starts most home fires! Isn't that an encouraging thought! Anyway, a little damn fuse in the plug would not have helped in this circumstance, complete waste of time, much like the main breaker was. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Roman, Dan dan.ro...@intel.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org Date: Thursday, October 25, 2001 7:41 AM Subject: RE: skinny power cords. I agreed completely with Scott. A 6 to 9 foot 18AWG cord will handle well in excess of 20A for a short period of time without starting to smoke (heck, it'll handle close to in excess of 60A for a very very short time without bursting into flames--not that it was a good experience finding this out). Point is, the cordage will handle a fault either indefinitely or long enough for the branch circuit breaker to trip provided you are connected to a 15A or 20A branch circuit. Another data point, you routinely pass more current through the cord when doing the earthing test and that uses more current than the cord is rated. Leave the tester on for awhile and the cord does not really heat up either. What this list needs is a power cord manufacturer or agency safety engineer that does power cords to settle this once and for all! Dan -Original Message- From: Scott Lacey [mailto:sco...@world.std.com] Sent: Wednesday, October 24, 2001 7:43 PM To: Gary McInturff Cc: emc-p...@majordomo.ieee.org Subject: RE: skinny power cords. Gary, I believe the answer is that the power cord rating of 6 or 10 amps is the operating current, at which it will have minimum temperature rise. Under fault conditions it will experience a rather dramatic temperature rise that is still well below the melting temperature
Safety warning symbols
Does anyone have, or know of a good source of, safety warning logos for machinery and equipment in vector graphic format? I'm thinking of things like logos to warn against things like entanglement hazards, crushing, noise etc. I don't mind paying for these if there is a resource which can provide them in a format which will save me from having to re-draw them. I can handle and edit most graphic file formats for either PC or Mac platforms. I specifically do not want scanned images since the resolution is unlikely to be sufficient. Regards Nick. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: skinny power cords.
Yes, I believe it was contamination. There is a tissue box on the night stand above the outlet. Tissue lint is insidious. The extension cord had been plugged in (AND LEFT UNDISTURBED) for a long period of time. Exactly, how the buildup made its way to an inside surface I don't know. But remember, an experienced fireman related that this is how most electrical fires start in his experience - an outlet shorts between blades (or in that area), the breaker does not trip while the arc is sustained, flames develop, and great damage occurs. I was upset that the 15A breaker could care less about the arc sizzling at the outlet. The reason I mention the extension cord is to point out that the plug plugged into the outlet was high quality and not a cheap lamp cord of suspect origin. Yet, this plug still carbonized AND FLAMED! making things much worse. Now, I do maintenance around our home using compressed air can to blow the outlet box clear of everything and unplug everything and wipe all surfaces clean. This has worked, but may not always, since sprays etc used in the area tend to produce a gummy, waxlike deposit on the outlet and there still may be stuff down inside. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Jim Eichner jim.eich...@xantrex.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, October 25, 2001 12:07 PM Subject: RE: skinny power cords. I'm curious: given that North American plug blades are 1/2 apart, there must have been substantial contamination to aid in 120Vac jumping that far (arcing). Did you identify any sort of contamination or moisture? Jim Eichner, P.Eng. Manager, Engineering Services Xantrex Technology Inc. Mobile Power phone: (604) 422-2546 fax: (604) 420-1591 e-mail: jim.eich...@xantrex.com web: www.xantrex.com -Original Message- From: Robert Macy [mailto:m...@california.com] Sent: Thursday, October 25, 2001 8:50 AM To: Roman, Dan; emc-p...@majordomo.ieee.org Subject: Re: skinny power cords. Just have to jump in here with personal experience: In our bedroom we have a deLonghi radiator heater which uses an extension cord (high cost UL approved) heavy guage #12 wire to power it - when it's used. This extension cord plugs into a multi outlet adapter, also heavy duty UL approved. At the time of the incident there was no power being used from this outlet. I was in another room, my wife was sitting on the edge of the bed watching a news blurb on TV when she heard a funny sound, a scritch, scritch. She called to me to come listen. Scritch, scritch, scritch got louder. As I arrived, flames started lapping up the wall from the outlet while still making arcing sounds. The flames were less than 6 inches from curtains. I reached into all this and unplugged the extension cord which luckily stopped the fireworks display. Imagine, if we had not been there. Upon examination, it appeared that an arc had formed between the blades of the extension cord (remember no power at the time). That arc was not sufficient to drop the 15A breaker to the outlet, yet was sufficient to carbonize the UL approved material which further sustained the arc. I posted this to the newsgroup alt.home.repair where a fireman jumped in describing how this exact mechanism is what starts most home fires! Isn't that an encouraging thought! Anyway, a little damn fuse in the plug would not have helped in this circumstance, complete waste of time, much like the main breaker was. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Roman, Dan dan.ro...@intel.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org Date: Thursday, October 25, 2001 7:41 AM Subject: RE: skinny power cords. I agreed completely with Scott. A 6 to 9 foot 18AWG cord will handle well in excess of 20A for a short period of time without starting to smoke (heck, it'll handle close to in excess of 60A for a very very short time without bursting into flames--not that it was a good experience finding this out). Point is, the cordage will handle a fault either indefinitely or long enough for the branch circuit breaker to trip provided you are connected to a 15A or 20A branch circuit. Another data point, you routinely pass more current through the cord when doing the earthing test and that uses more current than the cord is rated. Leave the tester on for awhile and the cord does not really heat up either. What this list needs is a power cord manufacturer or agency safety
RE: Fish paper
-Original Message- From: James, Chris [mailto:c...@dolby.co.uk] Sent: Thursday, October 25, 2001 3:04 AM To: Price, Ed Cc: 'EMC-PSTC List' Subject: RE: Fish paper We have found that some of these vulcanised paper cards can be hydroscopic and result in leakage problems. A modern alternative is material such as Dupont Nomex 410. Chris -Original Message- From: Price, Ed [mailto:ed.pr...@cubic.com] Sent: 25 October 2001 04:05 To: 'EMC-PSTC List' Subject: Fish paper Here's an interesting reference to fish paper, from the Rane Audio Reference site: http://www.rane.com/digi-dic.html fishpaper An insulating paper, often fiber- or oilcloth-like, used in the construction of transformers and coils. [Historical Note: EP Coughlin of LMC Plasticsource http://www.lmcplasticsource.com/ writes: Although my roots go back in fibre to 1959 I have never seen any hard copy evidence noting the origin of the name 'fishpaper.' My initial experience in the fibre industry was with Taylor Fibre Company and the owner claimed roots back to Thomas Taylor of England who is credited with 'inventing' vulcanized fibre. Original patent was in Great Britain in 1859 and Thomas Taylor received a US patent in 1872 titled 'Improvements in the treatment of paper and paper-pulp.' The major use for vulcanized fibre eventually was in the electrical insulation field but, obviously, requirements for same did not exist in 1859. Although anecdotal, John Taylor (owner/founder of The Taylor Fibre Company) claimed that vulcanized fibre's initial use was in England's fish markets as table / bin liners. The resistance to fish oil and tearing of vulcanized fibre makes this a very plausible story.] Regards, Ed Chris: You are quite right to point out that limitation of fishpaper. About 30 years ago, I was involved in designing miniature EMI filters using multi-layer discoidal ceramic capacitors. A couple of rings of fishpaper were included to space a small toroidal inductor away from one face of the capacitor. We traced problems with potting-epoxy curing to trace finger-oil and moisture contamination from handling the fishpaper. We did a temporary fix by requiring all handling of the fishpaper be done with gloved hands. Later, we switched to a high-temperature nylon-like plastic. Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: skinny power cords.
Rich, Ok. That makes sense. Thanks for the follow-up. This is scary stuff! Jack Cook Xerox EMC Engineering -Original Message- From: Rich Nute [mailto:ri...@sdd.hp.com] Sent: Thursday, October 25, 2001 2:11 PM To: jack.c...@cax.usa.xerox.com Cc: emc-p...@majordomo.ieee.org Subject: Re: skinny power cords. Hi Jack: I'm having a problem with Rich's explanation in this particular case (I know it's often true, though). How did resisitive heating occur *without* current flow? It was clearly stated that the heater was switched OFF. I believe that the process I described takes a lot of time. It starts when the heater is first used, i.e., a heavy current through the plug and socket. The heating due to the contact resistance degrades the material between the blades of the plug due to pyrolysis, the decomposition of a material by heat alone. The decomposition results in unknown materials between the blades. Plastics are carbon-based. Decomposition of carbon-based materials tends to reduce the size of the molecule, and the material approaches pure carbon, a resistor. So, we can assume that these unknown materials are resistive. We will have a leakage current through the resistance. Once the leakage path is established, the heater does not need to be on for the process to continue. Since this isn't a good resistance, some elements will open, and micro-arcs will occur. These micro- arcs create new resistances, and the leakage current will continue to increase. And the arcs get bigger. Etc. I could be wrong... Best regards, Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: skinny power cords.
Hi Jack: I'm having a problem with Rich's explanation in this particular case (I know it's often true, though). How did resisitive heating occur *without* current flow? It was clearly stated that the heater was switched OFF. I believe that the process I described takes a lot of time. It starts when the heater is first used, i.e., a heavy current through the plug and socket. The heating due to the contact resistance degrades the material between the blades of the plug due to pyrolysis, the decomposition of a material by heat alone. The decomposition results in unknown materials between the blades. Plastics are carbon-based. Decomposition of carbon-based materials tends to reduce the size of the molecule, and the material approaches pure carbon, a resistor. So, we can assume that these unknown materials are resistive. We will have a leakage current through the resistance. Once the leakage path is established, the heater does not need to be on for the process to continue. Since this isn't a good resistance, some elements will open, and micro-arcs will occur. These micro- arcs create new resistances, and the leakage current will continue to increase. And the arcs get bigger. Etc. I could be wrong... Best regards, Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: NEC Question BUT REMEMBER OSHA
Jacob, I would imagine that when the electrical inspector came in to review the electrical connections of that computerized, T1 hooked up brand new home, there would be an issue that would relate to the NEC. Scott Jacob Schanker wrote: Rich: You are implying, but not stating, that NEC has the force of law regarding the domestic environment. This differs with my understanding, or lack thereof. I have always regarded the National Electric Code as a recommended set of standards and practices which enabled localities to reference NEC in their local building codes, rather than develop their own from scratch. Perhaps you can expand on where the force of law applies to the NEC with regard to portable, plug-in (not permanently wired) home appliances and such? Jack Jacob Z. Schanker, P.E. 65 Crandon Way Rochester, NY 14618 Phone: 716 442 3909 Fax: 716 442 2182 j.schan...@ieee.org - Original Message - From: Rich Nute ri...@sdd.hp.com To: gkerv...@eu-link.com Cc: schan...@frontiernet.net; wo...@sensormatic.com; emc-p...@majordomo.ieee.org; mi...@ucentric.com Sent: Thursday, October 25, 2001 2:32 PM Subject: Re: NEC Question BUT REMEMBER OSHA | | | | Hi Gregg: | | |Just to ensure that I have my understanding right - if the equipment is used |where OSHA applies then it must be approved by a third party like UL | | Yes. More specifically: | |If... the product is used by an employee in the workplace... | |Then... the product must be certified by an NRTL, |of which UL is one. | |If it is domestic then it does not (in most states. | | No and yes. | | No, OSHA rules do not apply to a domestic place. | | Yes, NEC rules apply to a domestic place and do | require third-party safety certification. | | OSHA rules apply to the workplace, not to domestic places. | So, domestic places are not required -by OSHA- to have | NRTL-certified products. | | HOWEVER, the National Electrical Code applies everywhere, | including domestic places. The NEC requires products, | including domestic products, to be listed by a third- | party engaged in the safety evaluation of products. | | The NEC does not specify the third-party. During the | process of adoption of the NEC by various city, county, | or state governments, the government agency decides | which certification houses are acceptable to them. The | acceptable certification houses are published locally. | | For a third-party certifier, this means the certifier | must not only apply to OSHA for NRTL, but must also | apply to every jurisdiction in the USA for acceptance | under the NEC. | | Many, but not all NRTLs are also accepted by the various | city, county, or state governments under the local version | of the NEC. | | Likewise, there are some certifiers who are accepted by | one or more governments under the NEC, but are not NRTLs. | | There are a few pockets where local governments do not | require listing under the NEC. | | In summary: | | OSHA requires products used in the workplace to be | certified by an NRTL. | | The NEC requires products used in an installation | (including domestic places) to be certified by an | organization designated by the local government | agency charged with enforcing the NEC. | | These are independent functions. | | For all practical purposes, third-party safety certification | is required throughout the USA. | | Enforcement of both OSHA and NEC for cord-connected products | is spotty at best. | | Since virtually all products are NRTL-certified, OSHA spends | its time addressing more immediate workplace safety issues. | | Since cord-connected products are installed AFTER the | electrical installation is complete and approved, and since | virtually all products are safety-certified, there is little | or no enforcement of NEC-required certification. | |AND, does anyone have a list of States where certification is mandated? | | I would be easier to come up with a list of where certification | is NOT required! :-) It would be a one-page list of cities | or counties which have very low population densities. | | | Best regards, | Rich | | | | | | | --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer
RE: Shrunk-die power MOSFET's and compliance
The practice of die shrinking speedups causes problems in the digital IC arena also. The old but once heavily used 8051 processor is an example. Original designs were with the NMOS (HMOS?) version but later began being replaced by faster CMOS versions. We could see some of that clearly in certain product audits. Jack Cook, Xerox EMC Engineering -Original Message- From: Dan Kwok [mailto:dk...@intetron.com] Sent: Thursday, October 25, 2001 1:16 PM To: Jim Eichner; 'EMC-PSTC - forum' Subject: Re: Shrunk-die power MOSFET's and compliance Jim, You have my sympathies. Some manufacturers don't seem to realize that their so called product improvements may actually cause undue grief and hardships on their customers. Specifications subject to change without notice is a common catch clause associated with far many products on the market these days. In one company where I worked many years ago, we had an incoming inspection department that routinely carried out random samplings and measured critical parameters for crystals and semiconductors. With this approach, most out-of-spec devices simply did not make it to the store bins. On the brighter side, speeding up a FET is hard to do. Slowing it down in a circuit is much easier for EMC purposes. - Dan Kwok, P.Eng. Principal Engineer Electromagnetic Compatibility Intetron Consulting, Inc. Ph (604) 432-9874 E-mail dk...@intetron.com Internet http://www.intetron.com - Original Message - From: Jim Eichner jim.eich...@xantrex.com To: mertino...@skyskan.com; Jim Eichner jim.eich...@xantrex.com; 'EMC-PSTC - forum' emc-p...@majordomo.ieee.org Sent: Wednesday, October 24, 2001 11:54 AM Subject: RE: Shrunk-die power MOSFET's and compliance Well for example, I have just finished specifying what compliance re-testing I am going to need to do on 4 different products whose power conversion stages use IRF630's, IRF740's, IRF840's, and RFP50N06's, but the list goes on and on. If you are using power FET's in power electronics, chances are they have changed or will soon. The main manufacturers that come to mind are IR, Fairchild/Harris, Philips, and STM-Thomson. Not all have forced changes to the shrunk-die version - some have agreed to keep the old style available - and all have at least added a suffix to their markings on the devices so you can tell if it's the new revision die or old. In one case, however, we received modified parts with no markings differentiating them from the old rev parts, for almost a year with no communication from the mfr telling us about the change. We found out through other channels and then contacted them. They seem to be behaving as if fundamental changes to the performance and specifications of the part are none of our business. I am re-doing radiated and conducted emissions, some thermal testing, and a bunch of functional testing and looking at waveforms on 4 different products affected by this change. Those are only the products I am responsible for - as a company we're doing functional testing and possibly compliance re-testing on many more products. This is not a simple component substitution exercise, if your products are or use power electronics! I would advise everyone potentially affected to have your procurement department look into this. Regards, Jim Eichner, P.Eng. Manager, Engineering Services Xantrex Technology Inc. Mobile Power web: www.xantrex.com http://www.xantrex.com Any opinions expressed are those of my invisible friend, who really exists. Honest. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute:
RE: skinny power cords.
Got it - thanks for the explanation. Jim -Original Message- From: Rich Nute [mailto:ri...@sdd.hp.com] Sent: Thursday, October 25, 2001 1:58 PM To: jim.eich...@xantrex.com Cc: emc-p...@majordomo.ieee.org Subject: Re: skinny power cords. Hi Jim: Thanks Rich: I suspect you're right. Isn't that mechanism exactly what the tracking index tests are meant to address? I thought that any UL-approved wiring device like this would have a material that is designed to resist tracking, hence my speculation that contamination might be involved. No, I believe the UL tracking index tests do not address the scenario I described. My scenario starts with heating the insulating material to the point where it begins to pyrolyze, i.e., decompose by heat alone. The UL tracking index test starts with a drop of saline solution to provide a resistive path on the surface of the plastic insulator. The micro-arcs occur in the saline solution. In my scenario, pyrolysis, not pollution, leads to the micro-arcs. So, I don't believe the tracking index is necessarily a predictor of tracking due to pyrolysis. I could be wrong... Best regards, Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: skinny power cords.
Hi Jim: Thanks Rich: I suspect you're right. Isn't that mechanism exactly what the tracking index tests are meant to address? I thought that any UL-approved wiring device like this would have a material that is designed to resist tracking, hence my speculation that contamination might be involved. No, I believe the UL tracking index tests do not address the scenario I described. My scenario starts with heating the insulating material to the point where it begins to pyrolyze, i.e., decompose by heat alone. The UL tracking index test starts with a drop of saline solution to provide a resistive path on the surface of the plastic insulator. The micro-arcs occur in the saline solution. In my scenario, pyrolysis, not pollution, leads to the micro-arcs. So, I don't believe the tracking index is necessarily a predictor of tracking due to pyrolysis. I could be wrong... Best regards, Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
EFT Failures..Solved! - Part Substitution
I have made it a requirement here that the Compliance/Regulatory/Homologation/Approval Liaison engineer sign-off all engineering change orders (ECOs). There is such a space on the ECO form. (This is from my earlier days as a BABT Approval Liaison Eng. - ALE- where BABT required this of telecom companies). Additionally, 'Substitution Request Forms' that purchasing has to fill-out (and supply a sample and data sheet) at least minimizes surprises. While it is nearly impossible to fully retest the product every time a minor component change is made, it at least raises a flag and for critical components the appropriate tests are made in addition to reviewing data sheets. John Juhasz Fiber Options Bohemia, NY -Original Message- From: Jacob Schanker [mailto:schan...@frontiernet.net] Sent: Thursday, October 25, 2001 3:10 PM To: Alex McNeil; emc-p...@majordomo.ieee.org Subject: Re: EFT Failures..Solved!+ ESD symbol question Alex: Good Show. I am curious as to HOW the unfamiliar manufacturer's driver got into your product. It seems this was a costly substitution in terms of time and lab fees. I wonder if you are a victim of the Purchasing as a Profit Center Syndrome. This is the characteristic of too many organizations, where the purchasing agent has the authority (or takes it) to make parts substitutions on the basis of lower cost, or sometimes, social relationships. I've seen many cases of equivalent or as good as parts that were anything but. I shudder at the engineering hours I have seen wasted due to substitutions. The best approach I can offer is that parts should have approved and released engineering drawings which cannot be changed except by going through a formal change control process - which engineering either controls or participates in. Purchasing cannot purchase parts from a vendor who is not approved on the part drawing, except at their own career risk. Engineering change notices (a.k.a. Design change notices DCN) should require the approval, in some fashion, of the EMC and homologation person in the organization. I have used a check box on ECNs which say: _may affect EMC/EMI __ may affect approvals/homologation or something to that effect. This lets the originator do the alerting, and hopefully actually think about the broader implications of a change that is being contemplated. I'm sure that others on this forum have their own approaches, either personal or organizational. Perhaps they will share them. One last remark, and this applies also to vendors who change parts but not part numbers. An example being the smaller die sizes of FETs being discussed here lately. I have always found it helpful to keep a S-H-one-T list (SH1T) of rogue vendors not to buy from, and freely share the list with engineers and, yes, even purchasing. Cheers, Jack Jacob Z. Schanker, P.E. 65 Crandon Way Rochester, NY 14618 Phone: 716 442 3909 Fax: 716 442 2182 j.schan...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: skinny power cords.
Don't really have time for this, but ... I'm having a problem with Rich's explanation in this particular case (I know it's often true, though). How did resisitive heating occur *without* current flow? It was clearly stated that the heater was switched OFF. But then striking an arc between the flat blades is hard to explain also. An in-plug fuse would not have helped in that case. //Jack -Original Message- From: Jim Eichner [mailto:jim.eich...@xantrex.com] Sent: Thursday, October 25, 2001 12:40 PM Cc: emc-p...@majordomo.ieee.org Subject: RE: skinny power cords. Thanks Rich: I suspect you're right. Isn't that mechanism exactly what the tracking index tests are meant to address? I thought that any UL-approved wiring device like this would have a material that is designed to resist tracking, hence my speculation that contamination might be involved. I guess there are a few more comments to be made here... 1. From what I know, the tracking index tests are horribly non-repeatable and are therefore somewhat meaningless. 2. The standards for plug caps and for multi-taps may not refer to UL746 and may not have any of their own requirements for tracking index of insulation. 3. We could take this as evidence that even compliance with the tracking index requirements doesn't prevent carbonization of the material where there's a high temperature heat source involved. There are lots of people who unplug anything they are not actively using. I guess it's not such a paranoid practice! Regards, Jim Eichner, P.Eng. Manager, Engineering Services Xantrex Technology Inc. Mobile Power web: www.xantrex.com http://www.xantrex.com Any opinions expressed are those of my invisible friend, who really exists. Honest. -Original Message- From: Rich Nute [mailto:ri...@sdd.hp.com] Sent: Thursday, October 25, 2001 12:14 PM To: jim.eich...@xantrex.com Cc: emc-p...@majordomo.ieee.org Subject: Re: skinny power cords. Hi Jim: I'm curious: given that North American plug blades are 1/2 apart, there must have been substantial contamination to aid in 120Vac jumping that far (arcing). Did you identify any sort of contamination or moisture? I don't believe contamination is a significant factor in events such as this one. I believe such events start with a loose connection between the plug and the socket (or between the wire and the socket parts). A loose connection means that the contact area is relatively small. In turn, this means high current density at the point of contact. The smaller the contact area, the greater the resistance of the contact. The smaller the contact area, the greater the current density at the point of contact. These two factors contribute to heating of the two parts, the plug blade and the socket. Heating tends to reduce the springiness of the socket part, and of the connection between the supply wire and the socket (because they are thermally connected). The heating also tends to degrade the surface of the insulating material in which the conductors are mounted. Heating also enhances oxidation of the plating on the parts, which further increases the resistance of the connections. If the plug-connected appliance is ON, arcing can occur as the parts expand due to heating and make various intermittant connections. Arc temperatures are very high, and can burn the surface of nearby insulating materials via radiation. As the surface degrades, leakages occur across the surfaces. At this point, whether or not the appliance is on or even connected is not a factor. There is a current path between the two poles along the surface of the insulator. This can either be between the socket parts, or between the wired parts. The leakage current causes further heating and micro-arcs where the leakage path opens due to current density. The micro-arcs further damage the insulator until there is nearly continuous micro-arcing. I suggest this is the source of the noise. The heat from the micro- arcing and the resistance of the carbonized surface of the insulator eventually lead to ignition and flames. I admit that this is a hypothesis. I believe that the process is more-or-less correct, but the details may not be correct. Best regards, Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new
RE: Fish paper
Let's hear from others. Don't be squidish or shellfish and clam up on us. Sorry, the devil made me do it. -Original Message- From: Whitehouse, Terence (Terry) [mailto:twhiteho...@avaya.com] Sent: Thursday, October 25, 2001 3:54 PM To: 'Dan Teninty'; lcr...@tuvam.com; emc-p...@majordomo.ieee.org Subject: RE: Fish paper What a great grouper we are. With snapper responses we don't flounder around because - like Marlin Deitrich - we have got lots of sole. This laughter therapy is recommended by the Sturgeon General; so let's not change our tuna - there must be lots more to come.! Terry W. -Original Message- From: Dan Teninty [mailto:dteni...@dtec-associates.com] Sent: Thursday, October 25, 2001 10:05 AM To: lcr...@tuvam.com; emc-p...@majordomo.ieee.org Subject: RE: Fish paper I smelt that coming :) Dan DTEC Associates LLC http://www.dtec-associates.com http://www.dtec-associates.com/ Streamlining the Compliance Process 5406 S. Glendora Drive Spokane, WA 99223 (509) 443-0215 (509) 443-0181 fax -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of lcr...@tuvam.com Sent: Thursday, October 25, 2001 6:36 AM To: emc-p...@majordomo.ieee.org Subject: RE: Fish paper I think you have Perch'ed your argument rather precariously. Walleye understand where you are coming from, Salmon is sure to disagree with you. Best reference the National Electrical Cod. ;-) Lauren Crane -Original Message- From: wmf...@aol.com [ mailto:wmf...@aol.com mailto:wmf...@aol.com ] Sent: Thursday, October 25, 2001 7:04 AM To: emc-p...@majordomo.ieee.org Subject: RE: Fish paper Of course; after its namesake, fish paper could be expected to be hygroscopic. Or maybe someone just called it fish paper for the halibut. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Shrunk-die power MOSFET's and compliance
Jim, You have my sympathies. Some manufacturers don't seem to realize that their so called product improvements may actually cause undue grief and hardships on their customers. Specifications subject to change without notice is a common catch clause associated with far many products on the market these days. In one company where I worked many years ago, we had an incoming inspection department that routinely carried out random samplings and measured critical parameters for crystals and semiconductors. With this approach, most out-of-spec devices simply did not make it to the store bins. On the brighter side, speeding up a FET is hard to do. Slowing it down in a circuit is much easier for EMC purposes. - Dan Kwok, P.Eng. Principal Engineer Electromagnetic Compatibility Intetron Consulting, Inc. Ph (604) 432-9874 E-mail dk...@intetron.com Internet http://www.intetron.com - Original Message - From: Jim Eichner jim.eich...@xantrex.com To: mertino...@skyskan.com; Jim Eichner jim.eich...@xantrex.com; 'EMC-PSTC - forum' emc-p...@majordomo.ieee.org Sent: Wednesday, October 24, 2001 11:54 AM Subject: RE: Shrunk-die power MOSFET's and compliance Well for example, I have just finished specifying what compliance re-testing I am going to need to do on 4 different products whose power conversion stages use IRF630's, IRF740's, IRF840's, and RFP50N06's, but the list goes on and on. If you are using power FET's in power electronics, chances are they have changed or will soon. The main manufacturers that come to mind are IR, Fairchild/Harris, Philips, and STM-Thomson. Not all have forced changes to the shrunk-die version - some have agreed to keep the old style available - and all have at least added a suffix to their markings on the devices so you can tell if it's the new revision die or old. In one case, however, we received modified parts with no markings differentiating them from the old rev parts, for almost a year with no communication from the mfr telling us about the change. We found out through other channels and then contacted them. They seem to be behaving as if fundamental changes to the performance and specifications of the part are none of our business. I am re-doing radiated and conducted emissions, some thermal testing, and a bunch of functional testing and looking at waveforms on 4 different products affected by this change. Those are only the products I am responsible for - as a company we're doing functional testing and possibly compliance re-testing on many more products. This is not a simple component substitution exercise, if your products are or use power electronics! I would advise everyone potentially affected to have your procurement department look into this. Regards, Jim Eichner, P.Eng. Manager, Engineering Services Xantrex Technology Inc. Mobile Power web: www.xantrex.com http://www.xantrex.com Any opinions expressed are those of my invisible friend, who really exists. Honest. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: skinny power cords.
Hi Robert, Recently, I bought several similar heaters for my home. I recall reading in the operation instructions, explicit safety warnings against using extension cords with the heater. Was the extension cord supplied with the heater? - Dan Kwok, P.Eng. Principal Engineer Electromagnetic Compatibility Intetron Consulting, Inc. Ph (604) 432-9874 E-mail dk...@intetron.com Internet http://www.intetron.com - Original Message - From: Robert Macy m...@california.com To: Roman, Dan dan.ro...@intel.com; emc-p...@majordomo.ieee.org Sent: Thursday, October 25, 2001 8:49 AM Subject: Re: skinny power cords. Just have to jump in here with personal experience: In our bedroom we have a deLonghi radiator heater which uses an extension cord (high cost UL approved) heavy guage #12 wire to power it - when it's used. This extension cord plugs into a multi outlet adapter, also heavy duty UL approved. At the time of the incident there was no power being used from this outlet. I was in another room, my wife was sitting on the edge of the bed watching a news blurb on TV when she heard a funny sound, a scritch, scritch. She called to me to come listen. Scritch, scritch, scritch got louder. As I arrived, flames started lapping up the wall from the outlet while still making arcing sounds. The flames were less than 6 inches from curtains. I reached into all this and unplugged the extension cord which luckily stopped the fireworks display. Imagine, if we had not been there. Upon examination, it appeared that an arc had formed between the blades of the extension cord (remember no power at the time). That arc was not sufficient to drop the 15A breaker to the outlet, yet was sufficient to carbonize the UL approved material which further sustained the arc. I posted this to the newsgroup alt.home.repair where a fireman jumped in describing how this exact mechanism is what starts most home fires! Isn't that an encouraging thought! Anyway, a little damn fuse in the plug would not have helped in this circumstance, complete waste of time, much like the main breaker was. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Roman, Dan dan.ro...@intel.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org Date: Thursday, October 25, 2001 7:41 AM Subject: RE: skinny power cords. I agreed completely with Scott. A 6 to 9 foot 18AWG cord will handle well in excess of 20A for a short period of time without starting to smoke (heck, it'll handle close to in excess of 60A for a very very short time without bursting into flames--not that it was a good experience finding this out). Point is, the cordage will handle a fault either indefinitely or long enough for the branch circuit breaker to trip provided you are connected to a 15A or 20A branch circuit. Another data point, you routinely pass more current through the cord when doing the earthing test and that uses more current than the cord is rated. Leave the tester on for awhile and the cord does not really heat up either. What this list needs is a power cord manufacturer or agency safety engineer that does power cords to settle this once and for all! Dan -Original Message- From: Scott Lacey [mailto:sco...@world.std.com] Sent: Wednesday, October 24, 2001 7:43 PM To: Gary McInturff Cc: emc-p...@majordomo.ieee.org Subject: RE: skinny power cords. Gary, I believe the answer is that the power cord rating of 6 or 10 amps is the operating current, at which it will have minimum temperature rise. Under fault conditions it will experience a rather dramatic temperature rise that is still well below the melting temperature of the insulation. The breaker or fuse should clear well before the cord is cooked to the point of failure. Scott Lacey --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. ---
RE: Fish paper
What a great grouper we are. With snapper responses we don't flounder around because - like Marlin Deitrich - we have got lots of sole. This laughter therapy is recommended by the Sturgeon General; so let's not change our tuna - there must be lots more to come.! Terry W. -Original Message- From: Dan Teninty [mailto:dteni...@dtec-associates.com] Sent: Thursday, October 25, 2001 10:05 AM To: lcr...@tuvam.com; emc-p...@majordomo.ieee.org Subject: RE: Fish paper I smelt that coming :) Dan DTEC Associates LLC http://www.dtec-associates.com http://www.dtec-associates.com/ Streamlining the Compliance Process 5406 S. Glendora Drive Spokane, WA 99223 (509) 443-0215 (509) 443-0181 fax -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of lcr...@tuvam.com Sent: Thursday, October 25, 2001 6:36 AM To: emc-p...@majordomo.ieee.org Subject: RE: Fish paper I think you have Perch'ed your argument rather precariously. Walleye understand where you are coming from, Salmon is sure to disagree with you. Best reference the National Electrical Cod. ;-) Lauren Crane -Original Message- From: wmf...@aol.com [ mailto:wmf...@aol.com mailto:wmf...@aol.com ] Sent: Thursday, October 25, 2001 7:04 AM To: emc-p...@majordomo.ieee.org Subject: RE: Fish paper Of course; after its namesake, fish paper could be expected to be hygroscopic. Or maybe someone just called it fish paper for the halibut. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: NEC Question BUT REMEMBER OSHA
Unfortunately, compliance to the NEC is only required if the local or state government adopts it. Even then, they are not required to adopt any specific edition of the NEC. There are communities that are still using older editions as their current code. Some states have their own electrical codes, which they feel are better than NEC's. So, there are no absolutes about this subject. -Original Message- From: Rich Nute [mailto:ri...@sdd.hp.com] Sent: Thursday, October 25, 2001 2:32 PM To: gkerv...@eu-link.com Cc: schan...@frontiernet.net; wo...@sensormatic.com; emc-p...@majordomo.ieee.org; mi...@ucentric.com Subject: Re: NEC Question BUT REMEMBER OSHA Hi Gregg: Just to ensure that I have my understanding right - if the equipment is used where OSHA applies then it must be approved by a third party like UL Yes. More specifically: If... the product is used by an employee in the workplace... Then... the product must be certified by an NRTL, of which UL is one. If it is domestic then it does not (in most states. No and yes. No, OSHA rules do not apply to a domestic place. Yes, NEC rules apply to a domestic place and do require third-party safety certification. OSHA rules apply to the workplace, not to domestic places. So, domestic places are not required -by OSHA- to have NRTL-certified products. HOWEVER, the National Electrical Code applies everywhere, including domestic places. The NEC requires products, including domestic products, to be listed by a third- party engaged in the safety evaluation of products. The NEC does not specify the third-party. During the process of adoption of the NEC by various city, county, or state governments, the government agency decides which certification houses are acceptable to them. The acceptable certification houses are published locally. For a third-party certifier, this means the certifier must not only apply to OSHA for NRTL, but must also apply to every jurisdiction in the USA for acceptance under the NEC. Many, but not all NRTLs are also accepted by the various city, county, or state governments under the local version of the NEC. Likewise, there are some certifiers who are accepted by one or more governments under the NEC, but are not NRTLs. There are a few pockets where local governments do not require listing under the NEC. In summary: OSHA requires products used in the workplace to be certified by an NRTL. The NEC requires products used in an installation (including domestic places) to be certified by an organization designated by the local government agency charged with enforcing the NEC. These are independent functions. For all practical purposes, third-party safety certification is required throughout the USA. Enforcement of both OSHA and NEC for cord-connected products is spotty at best. Since virtually all products are NRTL-certified, OSHA spends its time addressing more immediate workplace safety issues. Since cord-connected products are installed AFTER the electrical installation is complete and approved, and since virtually all products are safety-certified, there is little or no enforcement of NEC-required certification. AND, does anyone have a list of States where certification is mandated? I would be easier to come up with a list of where certification is NOT required! :-) It would be a one-page list of cities or counties which have very low population densities. Best regards, Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on
Re: FCC Class A and Class B testing
Cecil, With that low a price point for the Photo Color Printer, unless you have a completely weird interface you will not convince the FCC that it is an industrial-use-only device. Some consumers will want to buy it, so you will have to test to Class B. If you do a good job of designing the printer, there should be little or no cost difference between just meeting Class A and easily meeting Class B. You can expect to spend a little more time in the EMC chamber to meet Class B... If you have a 100BASE-Tx Ethernet or 16Mbps Token-Ring interface on the printer, you may have a struggle getting it down to Class B. If you have a choice of shielded or unshielded connectors, make provisions for installing shielded connectors and for tying them to chassis ground with a short wide connection: * Metal standoffs holding the connector face tight against the chassis-- parallel and serial ports. * Metal tab on the connector shield clamped to the chassis with a metal screw-- USB, IEEE 1394. * A strip of copper tape if you have no other options, but manufacturing folks hate this because they cut their fingers on the sharp edges of the tape. John Barnes Advisory Engineer Lexmark International --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: skinny power cords.
Thanks Rich: I suspect you're right. Isn't that mechanism exactly what the tracking index tests are meant to address? I thought that any UL-approved wiring device like this would have a material that is designed to resist tracking, hence my speculation that contamination might be involved. I guess there are a few more comments to be made here... 1. From what I know, the tracking index tests are horribly non-repeatable and are therefore somewhat meaningless. 2. The standards for plug caps and for multi-taps may not refer to UL746 and may not have any of their own requirements for tracking index of insulation. 3. We could take this as evidence that even compliance with the tracking index requirements doesn't prevent carbonization of the material where there's a high temperature heat source involved. There are lots of people who unplug anything they are not actively using. I guess it's not such a paranoid practice! Regards, Jim Eichner, P.Eng. Manager, Engineering Services Xantrex Technology Inc. Mobile Power web: www.xantrex.com http://www.xantrex.com Any opinions expressed are those of my invisible friend, who really exists. Honest. -Original Message- From: Rich Nute [mailto:ri...@sdd.hp.com] Sent: Thursday, October 25, 2001 12:14 PM To: jim.eich...@xantrex.com Cc: emc-p...@majordomo.ieee.org Subject: Re: skinny power cords. Hi Jim: I'm curious: given that North American plug blades are 1/2 apart, there must have been substantial contamination to aid in 120Vac jumping that far (arcing). Did you identify any sort of contamination or moisture? I don't believe contamination is a significant factor in events such as this one. I believe such events start with a loose connection between the plug and the socket (or between the wire and the socket parts). A loose connection means that the contact area is relatively small. In turn, this means high current density at the point of contact. The smaller the contact area, the greater the resistance of the contact. The smaller the contact area, the greater the current density at the point of contact. These two factors contribute to heating of the two parts, the plug blade and the socket. Heating tends to reduce the springiness of the socket part, and of the connection between the supply wire and the socket (because they are thermally connected). The heating also tends to degrade the surface of the insulating material in which the conductors are mounted. Heating also enhances oxidation of the plating on the parts, which further increases the resistance of the connections. If the plug-connected appliance is ON, arcing can occur as the parts expand due to heating and make various intermittant connections. Arc temperatures are very high, and can burn the surface of nearby insulating materials via radiation. As the surface degrades, leakages occur across the surfaces. At this point, whether or not the appliance is on or even connected is not a factor. There is a current path between the two poles along the surface of the insulator. This can either be between the socket parts, or between the wired parts. The leakage current causes further heating and micro-arcs where the leakage path opens due to current density. The micro-arcs further damage the insulator until there is nearly continuous micro-arcing. I suggest this is the source of the noise. The heat from the micro- arcing and the resistance of the carbonized surface of the insulator eventually lead to ignition and flames. I admit that this is a hypothesis. I believe that the process is more-or-less correct, but the details may not be correct. Best regards, Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: NEC Question BUT REMEMBER OSHA
Hi Jack: You are implying, but not stating, that NEC has the force of law regarding the domestic environment. I meant to state that the NEC does indeed have the force of law not only for the domestic environment but for all electrical installations within the scope of the NEC. This differs with my understanding, or lack thereof. I have always regarded the National Electric Code as a recommended set of standards and practices which enabled localities to reference NEC in their local building codes, rather than develop their own from scratch. The NEC as published by the NFPA is indeed a recommended code. It is specifically offered to authorities for adoption as their Code. For example, the States of Oregon and Washington adopt each edition of the Code. The adoption is NOT a reference, but a true establishment of the NEC as the local Electrical Code, i.e., a regulation under the law. (Most authorities adopting the Code also have a few variations as well as identification of accepted safety certification houses. Sometimes, this is a pamphlet that supplements the NEC book.) However, various governments do indeed develop their own electrical code. The cities of Chicago and Los Angeles are two examples. Perhaps you can expand on where the force of law applies to the NEC with regard to portable, plug-in (not permanently wired) home appliances and such? The adoption of the Code makes the Code a regulation under the law. Usually the law is the one that establishes the Building Code, of which the Electrical Code is a part. I recently posted a message specifically identifying the NEC Articles that specify third-party safety certification of appliances. I hope this answers your question! Best regards, Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: skinny power cords.
Hi Jim: I'm curious: given that North American plug blades are 1/2 apart, there must have been substantial contamination to aid in 120Vac jumping that far (arcing). Did you identify any sort of contamination or moisture? I don't believe contamination is a significant factor in events such as this one. I believe such events start with a loose connection between the plug and the socket (or between the wire and the socket parts). A loose connection means that the contact area is relatively small. In turn, this means high current density at the point of contact. The smaller the contact area, the greater the resistance of the contact. The smaller the contact area, the greater the current density at the point of contact. These two factors contribute to heating of the two parts, the plug blade and the socket. Heating tends to reduce the springiness of the socket part, and of the connection between the supply wire and the socket (because they are thermally connected). The heating also tends to degrade the surface of the insulating material in which the conductors are mounted. Heating also enhances oxidation of the plating on the parts, which further increases the resistance of the connections. If the plug-connected appliance is ON, arcing can occur as the parts expand due to heating and make various intermittant connections. Arc temperatures are very high, and can burn the surface of nearby insulating materials via radiation. As the surface degrades, leakages occur across the surfaces. At this point, whether or not the appliance is on or even connected is not a factor. There is a current path between the two poles along the surface of the insulator. This can either be between the socket parts, or between the wired parts. The leakage current causes further heating and micro-arcs where the leakage path opens due to current density. The micro-arcs further damage the insulator until there is nearly continuous micro-arcing. I suggest this is the source of the noise. The heat from the micro- arcing and the resistance of the carbonized surface of the insulator eventually lead to ignition and flames. I admit that this is a hypothesis. I believe that the process is more-or-less correct, but the details may not be correct. Best regards, Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: EFT Failures..Solved!+ ESD symbol question
Alex: Good Show. I am curious as to HOW the unfamiliar manufacturer's driver got into your product. It seems this was a costly substitution in terms of time and lab fees. I wonder if you are a victim of the Purchasing as a Profit Center Syndrome. This is the characteristic of too many organizations, where the purchasing agent has the authority (or takes it) to make parts substitutions on the basis of lower cost, or sometimes, social relationships. I've seen many cases of equivalent or as good as parts that were anything but. I shudder at the engineering hours I have seen wasted due to substitutions. The best approach I can offer is that parts should have approved and released engineering drawings which cannot be changed except by going through a formal change control process - which engineering either controls or participates in. Purchasing cannot purchase parts from a vendor who is not approved on the part drawing, except at their own career risk. Engineering change notices (a.k.a. Design change notices DCN) should require the approval, in some fashion, of the EMC and homologation person in the organization. I have used a check box on ECNs which say: _may affect EMC/EMI __ may affect approvals/homologation or something to that effect. This lets the originator do the alerting, and hopefully actually think about the broader implications of a change that is being contemplated. I'm sure that others on this forum have their own approaches, either personal or organizational. Perhaps they will share them. One last remark, and this applies also to vendors who change parts but not part numbers. An example being the smaller die sizes of FETs being discussed here lately. I have always found it helpful to keep a S-H-one-T list (SH1T) of rogue vendors not to buy from, and freely share the list with engineers and, yes, even purchasing. Cheers, Jack Jacob Z. Schanker, P.E. 65 Crandon Way Rochester, NY 14618 Phone: 716 442 3909 Fax: 716 442 2182 j.schan...@ieee.org - Original Message - From: Alex McNeil alex.mcn...@ingenicofortronic.com To: emc-p...@majordomo.ieee.org Sent: Thursday, October 25, 2001 10:04 AM Subject: EFT Failures..Solved!+ ESD symbol question | | Hi Group, | | The problem was an oversensitive Display driver. Replacing this driver | solved my problem. | | It was diagnosed by: | 1. Was the problem due to conductive or radiated or both? By using the | DC lead, made a small loop, as my noise source with EFT test running, I | noticed the problem occurring near the display circuitry. The fault was | actually a Display lock whereas I thought it was a keyboard lock (same | symptons). I then attached my large ferrite core to the DC cable, several | turns, and repeated the test. No problems. I assumed from this that radiated | was the problem. | 2. What was actually picking up the noise and was the fault the display | driver? I assumed the cable connected to my display was picking up this | noise and conductively passing it on to the display driver. I could not | bypass the problem using caps, functionality started to play up a bit | depending on my value of capacitor. It was at this time I noticed that we | were using an unfamiliar driver manufacturer! I went to the stores and found | the proper part, fitted it and BINGO it now passes up to 3KV | | I am relatively new to this forum. but I think it a good idea if we all | share our problems and diagnostics. I am sure this would be a great help to | many of us!! | | However, for my next question? | | I want to place a Static Sensitive Area symbol on my product molding, | avoiding words, as it will be a worldwide product. The suymbol will be | explained in the user guide. | | Q. Is there a worldwide symbol to denote a Static Sensitive Area or a | European one and another North American one or I would need the .bmp | file if possible? | | Kind Regards | Alex McNeil | Principal Engineer | Tel: +44 (0)131 479 8375 | Fax: +44 (0)131 479 8321 | email: alex.mcn...@ingenicofortronic.com | | -Original Message- | From: Alex McNeil | Sent: Tuesday, October 23, 2001 9:44 AM | To: 'emc-p...@majordomo.ieee.org' | Subject: EFT Failures..Update! | | | Hi Group, | | THANKS for your very much appreciated responses!! I was in | panic mode!! | | I thought it would be appropriate to let you know the | status. | | My product is a small all plastic enclosure Point if Sale | (POS) Class III terminal. It has an external SMPS, Class II, no earth, | supplying SELV, 12Vdc 1.5A to my product. The power supply works OK with | some of our other products, for EMC. The problem is with my product. | | I solved the problem at the test house by wrapping a few | turns of the DC PSU cable through a Large Ferrite Clamp at the Product | input (it did not work so well at the PSU I/P nor O/P). The fix cannot be | considered final due to obvious reasons. | | I am now at my Lab, now the serious diagnostics begin. I | have been trying various quick fixes
Re: skinny power cords.
No soldered connections. The arc was external to the plug between the blades. Carbonizing and then cutting more carbon in the burn track. Remember the arc was *between* the blades, there was no power going through the cord itself. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Ron Pickard rpick...@hypercom.com To: m...@california.com m...@california.com Cc: emc-p...@ieee.org emc-p...@ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, October 25, 2001 11:01 AM Subject: Re: skinny power cords. Hi Robert, In your examination, did you find evidence of compression connections with soldered(tinned) leads? Or, did the compression connections appeared to be loose?. As you might already know, the solder in such a connection cold flows under the pressure of the connection and after a while this connection loosens. In my experience, this loose connection is the source where the arcing occurs. Comments anyone? Best regards, Ron Pickard rpick...@hypercom.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: NEC Question BUT REMEMBER OSHA
Rich: You are implying, but not stating, that NEC has the force of law regarding the domestic environment. This differs with my understanding, or lack thereof. I have always regarded the National Electric Code as a recommended set of standards and practices which enabled localities to reference NEC in their local building codes, rather than develop their own from scratch. Perhaps you can expand on where the force of law applies to the NEC with regard to portable, plug-in (not permanently wired) home appliances and such? Jack Jacob Z. Schanker, P.E. 65 Crandon Way Rochester, NY 14618 Phone: 716 442 3909 Fax: 716 442 2182 j.schan...@ieee.org - Original Message - From: Rich Nute ri...@sdd.hp.com To: gkerv...@eu-link.com Cc: schan...@frontiernet.net; wo...@sensormatic.com; emc-p...@majordomo.ieee.org; mi...@ucentric.com Sent: Thursday, October 25, 2001 2:32 PM Subject: Re: NEC Question BUT REMEMBER OSHA | | | | Hi Gregg: | | |Just to ensure that I have my understanding right - if the equipment is used |where OSHA applies then it must be approved by a third party like UL | | Yes. More specifically: | |If... the product is used by an employee in the workplace... | |Then... the product must be certified by an NRTL, |of which UL is one. | |If it is domestic then it does not (in most states. | | No and yes. | | No, OSHA rules do not apply to a domestic place. | | Yes, NEC rules apply to a domestic place and do | require third-party safety certification. | | OSHA rules apply to the workplace, not to domestic places. | So, domestic places are not required -by OSHA- to have | NRTL-certified products. | | HOWEVER, the National Electrical Code applies everywhere, | including domestic places. The NEC requires products, | including domestic products, to be listed by a third- | party engaged in the safety evaluation of products. | | The NEC does not specify the third-party. During the | process of adoption of the NEC by various city, county, | or state governments, the government agency decides | which certification houses are acceptable to them. The | acceptable certification houses are published locally. | | For a third-party certifier, this means the certifier | must not only apply to OSHA for NRTL, but must also | apply to every jurisdiction in the USA for acceptance | under the NEC. | | Many, but not all NRTLs are also accepted by the various | city, county, or state governments under the local version | of the NEC. | | Likewise, there are some certifiers who are accepted by | one or more governments under the NEC, but are not NRTLs. | | There are a few pockets where local governments do not | require listing under the NEC. | | In summary: | | OSHA requires products used in the workplace to be | certified by an NRTL. | | The NEC requires products used in an installation | (including domestic places) to be certified by an | organization designated by the local government | agency charged with enforcing the NEC. | | These are independent functions. | | For all practical purposes, third-party safety certification | is required throughout the USA. | | Enforcement of both OSHA and NEC for cord-connected products | is spotty at best. | | Since virtually all products are NRTL-certified, OSHA spends | its time addressing more immediate workplace safety issues. | | Since cord-connected products are installed AFTER the | electrical installation is complete and approved, and since | virtually all products are safety-certified, there is little | or no enforcement of NEC-required certification. | |AND, does anyone have a list of States where certification is mandated? | | I would be easier to come up with a list of where certification | is NOT required! :-) It would be a one-page list of cities | or counties which have very low population densities. | | | Best regards, | Rich | | | | | | | --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: skinny power cords.
I'm curious: given that North American plug blades are 1/2 apart, there must have been substantial contamination to aid in 120Vac jumping that far (arcing). Did you identify any sort of contamination or moisture? Jim Eichner, P.Eng. Manager, Engineering Services Xantrex Technology Inc. Mobile Power phone: (604) 422-2546 fax: (604) 420-1591 e-mail: jim.eich...@xantrex.com web: www.xantrex.com -Original Message- From: Robert Macy [mailto:m...@california.com] Sent: Thursday, October 25, 2001 8:50 AM To: Roman, Dan; emc-p...@majordomo.ieee.org Subject: Re: skinny power cords. Just have to jump in here with personal experience: In our bedroom we have a deLonghi radiator heater which uses an extension cord (high cost UL approved) heavy guage #12 wire to power it - when it's used. This extension cord plugs into a multi outlet adapter, also heavy duty UL approved. At the time of the incident there was no power being used from this outlet. I was in another room, my wife was sitting on the edge of the bed watching a news blurb on TV when she heard a funny sound, a scritch, scritch. She called to me to come listen. Scritch, scritch, scritch got louder. As I arrived, flames started lapping up the wall from the outlet while still making arcing sounds. The flames were less than 6 inches from curtains. I reached into all this and unplugged the extension cord which luckily stopped the fireworks display. Imagine, if we had not been there. Upon examination, it appeared that an arc had formed between the blades of the extension cord (remember no power at the time). That arc was not sufficient to drop the 15A breaker to the outlet, yet was sufficient to carbonize the UL approved material which further sustained the arc. I posted this to the newsgroup alt.home.repair where a fireman jumped in describing how this exact mechanism is what starts most home fires! Isn't that an encouraging thought! Anyway, a little damn fuse in the plug would not have helped in this circumstance, complete waste of time, much like the main breaker was. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Roman, Dan dan.ro...@intel.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, October 25, 2001 7:41 AM Subject: RE: skinny power cords. I agreed completely with Scott. A 6 to 9 foot 18AWG cord will handle well in excess of 20A for a short period of time without starting to smoke (heck, it'll handle close to in excess of 60A for a very very short time without bursting into flames--not that it was a good experience finding this out). Point is, the cordage will handle a fault either indefinitely or long enough for the branch circuit breaker to trip provided you are connected to a 15A or 20A branch circuit. Another data point, you routinely pass more current through the cord when doing the earthing test and that uses more current than the cord is rated. Leave the tester on for awhile and the cord does not really heat up either. What this list needs is a power cord manufacturer or agency safety engineer that does power cords to settle this once and for all! Dan -Original Message- From: Scott Lacey [mailto:sco...@world.std.com] Sent: Wednesday, October 24, 2001 7:43 PM To: Gary McInturff Cc: emc-p...@majordomo.ieee.org Subject: RE: skinny power cords. Gary, I believe the answer is that the power cord rating of 6 or 10 amps is the operating current, at which it will have minimum temperature rise. Under fault conditions it will experience a rather dramatic temperature rise that is still well below the melting temperature of the insulation. The breaker or fuse should clear well before the cord is cooked to the point of failure. Scott Lacey --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at:
Re: NEC Question BUT REMEMBER OSHA
Hi Gregg: Just to ensure that I have my understanding right - if the equipment is used where OSHA applies then it must be approved by a third party like UL Yes. More specifically: If... the product is used by an employee in the workplace... Then... the product must be certified by an NRTL, of which UL is one. If it is domestic then it does not (in most states. No and yes. No, OSHA rules do not apply to a domestic place. Yes, NEC rules apply to a domestic place and do require third-party safety certification. OSHA rules apply to the workplace, not to domestic places. So, domestic places are not required -by OSHA- to have NRTL-certified products. HOWEVER, the National Electrical Code applies everywhere, including domestic places. The NEC requires products, including domestic products, to be listed by a third- party engaged in the safety evaluation of products. The NEC does not specify the third-party. During the process of adoption of the NEC by various city, county, or state governments, the government agency decides which certification houses are acceptable to them. The acceptable certification houses are published locally. For a third-party certifier, this means the certifier must not only apply to OSHA for NRTL, but must also apply to every jurisdiction in the USA for acceptance under the NEC. Many, but not all NRTLs are also accepted by the various city, county, or state governments under the local version of the NEC. Likewise, there are some certifiers who are accepted by one or more governments under the NEC, but are not NRTLs. There are a few pockets where local governments do not require listing under the NEC. In summary: OSHA requires products used in the workplace to be certified by an NRTL. The NEC requires products used in an installation (including domestic places) to be certified by an organization designated by the local government agency charged with enforcing the NEC. These are independent functions. For all practical purposes, third-party safety certification is required throughout the USA. Enforcement of both OSHA and NEC for cord-connected products is spotty at best. Since virtually all products are NRTL-certified, OSHA spends its time addressing more immediate workplace safety issues. Since cord-connected products are installed AFTER the electrical installation is complete and approved, and since virtually all products are safety-certified, there is little or no enforcement of NEC-required certification. AND, does anyone have a list of States where certification is mandated? I would be easier to come up with a list of where certification is NOT required! :-) It would be a one-page list of cities or counties which have very low population densities. Best regards, Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Aircrafts
Amund, NAV Canada, formerly part of Transport Canada, which operates air navigation services, is a member of RTCA. Transport Canada also adopts RTCA/DO-160 for equipment aboard aircraft. - Dan Kwok, P.Eng. Principal Engineer Electromagnetic Compatibility Intetron Consulting, Inc. Ph (604) 432-9874 E-mail dk...@intetron.com Internet http://www.intetron.com - Original Message - From: am...@westin-emission.no To: emc-p...@majordomo.ieee.org Sent: Thursday, October 25, 2001 5:06 AM Subject: Aircrafts Hi all, Electrical equipment placed inside an aircraft (navigation equipment installed in the cockpit), are they required to fulfil the CE-regulations for use within EU? If yes, which directives apply ? EMC ? LVD ? What about in the US/Canada ? I have a feeling that RO-160D applies. Am I right ? Best regards Amund Westin --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: FCC Class A and Class B testing
FCC ID number is not necessarily required. They could use an accredited lab and go the DoC route. Faster route to market, too (don't have to wait for approval from a TCB). Ghery Pettit Intel -Original Message- From: John Juhasz [mailto:jjuh...@fiberoptions.com] Sent: Thursday, October 25, 2001 10:40 AM To: 'cecil.gitt...@kodak.com'; emc-p...@majordomo.ieee.org Subject: RE: FCC Class A and Class B testing Cecil, Cost here is not the issue. Market is the issue. If the product is put on the retail consumer market then it has to be Class B (requires an FCC ID number as well). If sales are limited to commercial (the average consumer could not obtain one) then Class A. If the sales will not be so restricted, then you will have to go Class B. John Juhasz FIber Options Bohemia, NY -Original Message- From: cecil.gitt...@kodak.com [mailto:cecil.gitt...@kodak.com] Sent: Thursday, October 25, 2001 12:15 PM To: emc-p...@majordomo.ieee.org Subject: FCC Class A and Class B testing From: Cecil A. Gittens I am in process in creating an EMC test plan for a Photo Color Printer that will be sold for about $1200.00. My question is can I test this product for either FCC Class A or B? Does the cost of a product matters if it is Class A or B for the US market? Cecil --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: skinny power cords.
Hi Robert, In your examination, did you find evidence of compression connections with soldered(tinned) leads? Or, did the compression connections appeared to be loose?. As you might already know, the solder in such a connection cold flows under the pressure of the connection and after a while this connection loosens. In my experience, this loose connection is the source where the arcing occurs. Comments anyone? Best regards, Ron Pickard rpick...@hypercom.com m...@california.com Sent by: To: dan.ro...@intel.com, emc-p...@majordomo.ieee.org owner-emc-pstc@majordomcc: o.ieee.org Subject: Re: skinny power cords. 10/25/01 08:49 AM Please respond to macy Just have to jump in here with personal experience: In our bedroom we have a deLonghi radiator heater which uses an extension cord (high cost UL approved) heavy guage #12 wire to power it - when it's used. This extension cord plugs into a multi outlet adapter, also heavy duty UL approved. At the time of the incident there was no power being used from this outlet. I was in another room, my wife was sitting on the edge of the bed watching a news blurb on TV when she heard a funny sound, a scritch, scritch. She called to me to come listen. Scritch, scritch, scritch got louder. As I arrived, flames started lapping up the wall from the outlet while still making arcing sounds. The flames were less than 6 inches from curtains. I reached into all this and unplugged the extension cord which luckily stopped the fireworks display. Imagine, if we had not been there. Upon examination, it appeared that an arc had formed between the blades of the extension cord (remember no power at the time). That arc was not sufficient to drop the 15A breaker to the outlet, yet was sufficient to carbonize the UL approved material which further sustained the arc. I posted this to the newsgroup alt.home.repair where a fireman jumped in describing how this exact mechanism is what starts most home fires! Isn't that an encouraging thought! Anyway, a little damn fuse in the plug would not have helped in this circumstance, complete waste of time, much like the main breaker was. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Roman, Dan dan.ro...@intel.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, October 25, 2001 7:41 AM Subject: RE: skinny power cords. I agreed completely with Scott. A 6 to 9 foot 18AWG cord will handle well in excess of 20A for a short period of time without starting to smoke (heck, it'll handle close to in excess of 60A for a very very short time without bursting into flames--not that it was a good experience finding this out). Point is, the cordage will handle a fault either indefinitely or long enough for the branch circuit breaker to trip provided you are connected to a 15A or 20A branch circuit. Another data point, you routinely pass more current through the cord when doing the earthing test and that uses more current than the cord is rated. Leave the tester on for awhile and the cord does not really heat up either. What this list needs is a power cord manufacturer or agency safety engineer that does power cords to settle this once and for all! Dan -Original Message- From: Scott Lacey [mailto:sco...@world.std.com] Sent: Wednesday, October 24, 2001 7:43 PM To: Gary McInturff Cc: emc-p...@majordomo.ieee.org Subject: RE: skinny power cords. Gary, I believe the answer is that the power cord rating of 6 or 10 amps is the operating current, at which it will have
RE: FCC Class A and Class B testing
In my experience in the US (FCC regs.) Class B is for residential use and Class A is commercial business use. Class B products are products marketed to the general public [for use in the home] and Class A products are products marketed to Business [for use in the office]. The FCC regs. do not allow Class A products for use in the home and hence to be safe Class B is preferred and can be sold to home and business. In Europe the Class A/non-residential versus Class B/residential is not explicity detailed/stated in the emission standard. The FCC does state the difference between Class A and Class B usage. Andy White Ericsson San Diego. -Original Message- From: cecil.gitt...@kodak.com [mailto:cecil.gitt...@kodak.com] Sent: Thursday, October 25, 2001 9:15 AM To: emc-p...@majordomo.ieee.org Subject: FCC Class A and Class B testing From: Cecil A. Gittens I am in process in creating an EMC test plan for a Photo Color Printer that will be sold for about $1200.00. My question is can I test this product for either FCC Class A or B? Does the cost of a product matters if it is Class A or B for the US market? Cecil --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: FCC Class A and Class B testing
Cecil, Cost here is not the issue. Market is the issue. If the product is put on the retail consumer market then it has to be Class B (requires an FCC ID number as well). If sales are limited to commercial (the average consumer could not obtain one) then Class A. If the sales will not be so restricted, then you will have to go Class B. John Juhasz FIber Options Bohemia, NY -Original Message- From: cecil.gitt...@kodak.com [mailto:cecil.gitt...@kodak.com] Sent: Thursday, October 25, 2001 12:15 PM To: emc-p...@majordomo.ieee.org Subject: FCC Class A and Class B testing From: Cecil A. Gittens I am in process in creating an EMC test plan for a Photo Color Printer that will be sold for about $1200.00. My question is can I test this product for either FCC Class A or B? Does the cost of a product matters if it is Class A or B for the US market? Cecil --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: FCC Class A and Class B testing
Cecil, What matters is who the product will be marketed to. The cost has nothing to do with it. If this is a printer that is designed to be connected to a personal computer then it would be considered a digital device by the FCC. The fact that it is a digital device means that it must be tested to meet either Class A or Class B of part 15 of CFR 47. Here is what 47 CFR 15.3 Definitions has to say. 15.3 (h) Class A digital device. A digital device that is marketed for use in a commercial, industrial or business environment, exclusive of a device which is marketed for use by the general public or is intended to be used in the home. 15.3 (i) Class B digital device. A digital device that is marketed for use in a residential environment notwithstanding use in a commercial, business or industrial environments. Examples of such devices include, but are not limited to personal computers, calculators, and similar electronic devices that are marketed for use by the general public. NOTE: The responsible party may also qualify a device intended to be marketed in a commercial, business or industrial environment as a Class B device, and in fact is encouraged to do so, provided the device complies with the technical specifications for a Class B digital device. In the event that a particular type of device has been found to repeatedly cause harmful interference to radio communications, the Commission may classify such a digital device as a Class B digital device, regardless of its intended use. Kurt Andrews Compliance Engineer Tracewell Systems, Inc. 567 Enterprise Drive Westerville, Ohio 43081 voice: 614.846.6175 toll free: 800.848.4525 fax: 614.846.7791 http://www.tracewellsystems.com/ -Original Message- From: cecil.gitt...@kodak.com [mailto:cecil.gitt...@kodak.com] Sent: Thursday, October 25, 2001 12:15 PM To: emc-p...@majordomo.ieee.org Subject:FCC Class A and Class B testing From: Cecil A. Gittens I am in process in creating an EMC test plan for a Photo Color Printer that will be sold for about $1200.00. My question is can I test this product for either FCC Class A or B? Does the cost of a product matters if it is Class A or B for the US market? Cecil --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
FCC Class A and Class B testing
FCC looks at things like price, where advertised, where sold. If any of these look a lot like other consumer ITE, the verdict will be Class B. If it is advertised only in periodicals such as Forbes and the WSJ , and sold only through high end ITE outlets, to mainly buiness clients, then it might pass the Class A test. -- Forwarded by George Alspaugh/Lex/Lexmark on 10/25/2001 01:28 PM --- cecil.gittens%kodak@interlock.lexmark.com on 10/25/2001 12:14:51 PM Please respond to cecil.gittens%kodak@interlock.lexmark.com To: emc-pstc%majordomo.ieee@interlock.lexmark.com cc:(bcc: George Alspaugh/Lex/Lexmark) Subject: FCC Class A and Class B testing From: Cecil A. Gittens I am in process in creating an EMC test plan for a Photo Color Printer that will be sold for about $1200.00. My question is can I test this product for either FCC Class A or B? Does the cost of a product matters if it is Class A or B for the US market? Cecil --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: DC voltage ratings
In a message dated 10/25/01, Dave Heald writes: If you want to ship to Europe, the nominal voltage can be -60Vdc. Here it gets tricky as charging voltages are typically 72Vdc. Most NRTL's testing to the new UL60950 will treat DC input voltages at these levels as TNV-2, which is a lot better for design reasons than treating your input circuit as a hazardous voltage circuit. Hello All: Just a followup on Dave's comment above. In Europe (EN 60950), the definition of TNV voltages in clause 2.3.1 allows levels up to 120 VDC. In the USA there is a D2 deviation that severely limits the use of voltages over 60 VDC, but clause 3.6 of UL 60950 explicitly allows centralized DC supplies up to 80 VDC to be classified as TNV-2. Thus, depending on the specifics of the application, the 60 VDC limit in the UL definition of TNV is not a problem in Europe and may not be a problem in the USA either. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. http://www.randolph-telecom.com
RE: NEC Question BUT REMEMBER OSHA
Don't forget the Product Liability Lawyers ! ! Listing a product does not protect the manufacturer from being sued, it just establishes that the manufacturer has been duly diligent and therefore has not been negligent. This makes a huge difference when a lawsuit happens. In our society, where lawyers outnumber engineers, suit happens. Best regards, Dan DTEC Associates LLC http://www.dtec-associates.com Streamlining the Compliance Process 5406 S. Glendora Drive Spokane, WA 99223 (509) 443-0215 (509) 443-0181 fax -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Gregg Kervill Sent: Thursday, October 25, 2001 6:12 AM To: 'Jacob Schanker'; wo...@sensormatic.com; emc-p...@majordomo.ieee.org; mi...@ucentric.com Subject: RE: NEC Question BUT REMEMBER OSHA Just to ensure that I have my understanding right - if the equipment is used where OSHA applies then it must be approved by a third party like UL If it is domestic then it does not (in most states. Comments please. AND, does anyone have a list of States where certification is mandated? Best regards Gregg --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: Fish paper
RE: Fish paperI smelt that coming :) Dan DTEC Associates LLC http://www.dtec-associates.com Streamlining the Compliance Process 5406 S. Glendora Drive Spokane, WA 99223 (509) 443-0215 (509) 443-0181 fax -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of lcr...@tuvam.com Sent: Thursday, October 25, 2001 6:36 AM To: emc-p...@majordomo.ieee.org Subject: RE: Fish paper I think you have Perch'ed your argument rather precariously. Walleye understand where you are coming from, Salmon is sure to disagree with you. Best reference the National Electrical Cod. ;-) Lauren Crane -Original Message- From: wmf...@aol.com [mailto:wmf...@aol.com] Sent: Thursday, October 25, 2001 7:04 AM To: emc-p...@majordomo.ieee.org Subject: RE: Fish paper Of course; after its namesake, fish paper could be expected to be hygroscopic. Or maybe someone just called it fish paper for the halibut. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Aircrafts
Dear Amund, Typically, electrical equipment installed on aircraft do not use the EMC Directive and LV Directive, but rather the RTCA DO-160 (for commercial aviation) and MIL-STD-461E for military aviation. Those are for EMC. For power quality, there is a special part in DO-160 (Part 16/17, I think) for commercial aviation, and MIL-STD-704 for Military aviation. The LV Directive applies to equipment connected to the power network (on the ground). Those should apply worldwide. Not only in the US or Canada. Regards, Elya -- Original Message -- Hi all, Electrical equipment placed inside an aircraft (navigation equipment installed in the cockpit), are they required to fulfil the CE-regulations for use within EU? If yes, which directives apply ? EMC ? LVD ? What about in the US/Canada ? I have a feeling that RO-160D applies. Am I right ? Best regards Amund Westin --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: FCC Class A and Class B testing
Cecil, Is this product intended to be marketed to the general public for use in the home? If so, the FCC defines it as a class B device. Cost is not in the equation. Ghery Pettit Intel -Original Message- From: cecil.gitt...@kodak.com [mailto:cecil.gitt...@kodak.com] Sent: Thursday, October 25, 2001 9:15 AM To: emc-p...@majordomo.ieee.org Subject: FCC Class A and Class B testing From: Cecil A. Gittens I am in process in creating an EMC test plan for a Photo Color Printer that will be sold for about $1200.00. My question is can I test this product for either FCC Class A or B? Does the cost of a product matters if it is Class A or B for the US market? Cecil --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: Insulated Electrolytic Capacitors
It is my understanding the only X and Y type capacitors can be relied upon to provide basic insulation (my experience with IEC60065) From bitter experience I have learned that you can't rely on other products (or even your own previously approved products) for verification of conformity. The test engineer may have missed something - apparently they're only human(?). Regards Chris Colgan Compliance Engineer TAG McLaren Audio Ltd The Summit, Latham Road Huntingdon, Cambs, PE29 6ZU *Tel: +44 (0)1480 415 627 *Fax: +44 (0)1480 52159 * Mailto:chris.col...@tagmclaren.com * http://www.tagmclaren.com -Original Message- From: Peter Merguerian [SMTP:pmerguer...@itl.co.il] Sent: 24 October 2001 14:38 To: EMC-PSTC (E-mail) Subject: Insulated Electrolytic Capacitors Dear All, I have submitted an ac input to dc output switching power supply for NRTL approval. One deviation is that the primary ac insulated capacitor is too close to the earthed chassis and that the insulation cannot be relied to provide the required basic insulation. 1. What is the group's opinion regarding this point? I have personally seen many Listed/Recognized units with clearance distance less than 2.0 mm to the earthed chassis without any additional insulation to provide the required insulation. In fact, I am holding a switching power supply by a reputable manufacturer with only approx. 0.7 mm between the primary and earthed chassis. This power supply is UL Recognized and TUV approved. 2. There is a UL Pag 156002 regarding this issue, but it seems that some NRTL engineers are using their own judgement and approving units at their own discretion. This e-mail message may contain privileged or confidential information. If you are not the intended recipient, you may not disclose, use, disseminate, distribute, copy or rely upon this message or attachment in any way. If you received this e-mail message in error, please return by forwarding the message and its attachments to the sender. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: + 972-(0)3-5339022 Fax: + 972-(0)3-5339019 Mobile: + 972-(0)54-838175 --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. ** Please visit us at www.tagmclaren.com ** The contents of this E-mail are confidential and for the exclusive use of the intended recipient. If you receive this E-mail in error, please delete it from your system immediately and notify us either by E-mail, telephone or fax. You should not copy, forward or otherwise disclose the content of the E-mail. TAG McLaren Audio Ltd The Summit, 11 Latham Road Huntingdon, Cambs, PE29 6ZU Telephone : 01480 415600 (+44 1480 415600) Facsimile : 01480 52159 (+44 1480 52159) ** Please visit us at www.tagmclaren.com ** --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
FCC Class A and Class B testing
From: Cecil A. Gittens I am in process in creating an EMC test plan for a Photo Color Printer that will be sold for about $1200.00. My question is can I test this product for either FCC Class A or B? Does the cost of a product matters if it is Class A or B for the US market? Cecil --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: NEC Question
YES, FOR THE CONSUMER MARKET, THIS IS LIKE THE UNLISTED CHRISTMAS TREE LIGHTS INVASION EACH YEAR. -Original Message- From: Jacob Schanker [mailto:schan...@frontiernet.net] Sent: Thursday, October 25, 2001 11:34 AM To: Nikolassy, Anton; wo...@sensormatic.com; emc-p...@majordomo.ieee.org; mi...@ucentric.com Subject: Re: NEC Question Anton: Yes, I think you have summed it up nicely. Actually, I have found it very helpful, both for myself and for explaining to others, to consider the sociological background leading to regulations in the US and in Europe. Basically, the US, as I see it for this purpose, is a wild-west capitalist society. Anything goes and the market rules, unless we are told otherwise. The government protecting us from ourselves is a relatively recent development. Europe tends to paternalism and socialism. Government sets the rules and the rules protect the people. Maybe this stems from a history of monarchy and dictatorships. Anyways, the regulation writing business in Europe must certainly represent a significant part of the Gross National Product in EU countries. So, we have examples like EU requiring immunity testing/declaration of products before they are marketed. A consumer has a right to expect that the radio receiver or stereo amplifier or whatever they purchase will be reasonably immune from interference and disruption by unwanted signals. In the US, on the other hand, the FCC makes no requirements for immunity, only for emissions. Here, the marketplace is supposed to operate to eliminate faulty products which have poor immunity. Theory is that consumers will not buy these things. The trouble is that consumers DO buy these things, and that causes endless problems for people (like me) who are involved with radio/TV broadcasting, or other wireless transmitters. Put another way, in the US we have the freedom to buy crap and then complain about it. Back to topic: It has been accurately pointed out that employers/businesses have an obligation, under Federal Law, to use listed products for the safety of their workers. However, just to reiterate, equipment manufacturers have no legal obligation to list products before selling. Again, we see the marketplace. Why would a business buy anything other than a listed product? (The answer is generally ignorance of the requirement). Of course, I could be wrong. Regards, Jack Jacob Z. Schanker, P.E. 65 Crandon Way Rochester, NY 14618 Phone: 716 442 3909 Fax: 716 442 2182 j.schan...@ieee.org - Original Message - From: Nikolassy, Anton anton.nikola...@fmglobal.com To: 'Jacob Schanker' schan...@frontiernet.net; wo...@sensormatic.com; emc-p...@majordomo.ieee.org; mi...@ucentric.com Sent: Thursday, October 25, 2001 10:25 AM Subject: RE: NEC Question | This is a very interesting conversation. Basically you are saying that this | is America. Your allowed to be as liable as you want to be. | | Tony Nikolassy | FMRC | | -Original Message- | From: Jacob Schanker [mailto:schan...@frontiernet.net] | Sent: Wednesday, October 24, 2001 4:38 PM | To: wo...@sensormatic.com; emc-p...@majordomo.ieee.org; | mi...@ucentric.com | Subject: Re: NEC Question | | | | Mike: | | There is no Federal requirement for the manufacturer to have | equipment listed or NRTL approved. The requirements are set by | localities, as Richard Woods clearly points out. | | I can understand that in some companies, the powers-that-be | have little patience with the time and expense of obtaining a | listing. The delay in hitting the market is often more costly | than the approval process itself. | | I say TOUGH. They should have allowed for that in the original | project plan and schedule. There was one, wasn't there? | | If you are having a problem, just ask marketing to agree to | exclude the areas that Richard enumerated from their sales areas. | If it's OK to exclude LA, etc. etc., than listing isn't needed, | legally. | | But the competition may be listing, so not doing so puts you at a | disadvantage. | | I have asked managers to imagine sitting on the witness stand at | a product liability trial, and trying to answer the question, why | didn't you get safety approval from an NRTL? | | When the implications of shortcuts are driven home, most people | see the light. Those that don't need to stick their fingers in an | unlisted light socket. | | Rant concluded, best regards, | | Jack | | Jacob Z. Schanker, P.E. | 65 Crandon Way | Rochester, NY 14618 | Phone: 716 442 3909 | Fax: 716 442 2182 | j.schan...@ieee.org | | - Original Message - | From: wo...@sensormatic.com | To: emc-p...@majordomo.ieee.org | Sent: Wednesday, October 24, 2001 12:23 PM | Subject: RE: NEC Question | | | | | | Mike, regardless of what the NEC says, and it is not very clear | in this | | regard, it is the state, county and city electrical codes and | other local | | regulations that apply. Many jurisdictions have deviations from | the NEC | | and/or have other
Re: skinny power cords.
Just have to jump in here with personal experience: In our bedroom we have a deLonghi radiator heater which uses an extension cord (high cost UL approved) heavy guage #12 wire to power it - when it's used. This extension cord plugs into a multi outlet adapter, also heavy duty UL approved. At the time of the incident there was no power being used from this outlet. I was in another room, my wife was sitting on the edge of the bed watching a news blurb on TV when she heard a funny sound, a scritch, scritch. She called to me to come listen. Scritch, scritch, scritch got louder. As I arrived, flames started lapping up the wall from the outlet while still making arcing sounds. The flames were less than 6 inches from curtains. I reached into all this and unplugged the extension cord which luckily stopped the fireworks display. Imagine, if we had not been there. Upon examination, it appeared that an arc had formed between the blades of the extension cord (remember no power at the time). That arc was not sufficient to drop the 15A breaker to the outlet, yet was sufficient to carbonize the UL approved material which further sustained the arc. I posted this to the newsgroup alt.home.repair where a fireman jumped in describing how this exact mechanism is what starts most home fires! Isn't that an encouraging thought! Anyway, a little damn fuse in the plug would not have helped in this circumstance, complete waste of time, much like the main breaker was. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Roman, Dan dan.ro...@intel.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, October 25, 2001 7:41 AM Subject: RE: skinny power cords. I agreed completely with Scott. A 6 to 9 foot 18AWG cord will handle well in excess of 20A for a short period of time without starting to smoke (heck, it'll handle close to in excess of 60A for a very very short time without bursting into flames--not that it was a good experience finding this out). Point is, the cordage will handle a fault either indefinitely or long enough for the branch circuit breaker to trip provided you are connected to a 15A or 20A branch circuit. Another data point, you routinely pass more current through the cord when doing the earthing test and that uses more current than the cord is rated. Leave the tester on for awhile and the cord does not really heat up either. What this list needs is a power cord manufacturer or agency safety engineer that does power cords to settle this once and for all! Dan -Original Message- From: Scott Lacey [mailto:sco...@world.std.com] Sent: Wednesday, October 24, 2001 7:43 PM To: Gary McInturff Cc: emc-p...@majordomo.ieee.org Subject: RE: skinny power cords. Gary, I believe the answer is that the power cord rating of 6 or 10 amps is the operating current, at which it will have minimum temperature rise. Under fault conditions it will experience a rather dramatic temperature rise that is still well below the melting temperature of the insulation. The breaker or fuse should clear well before the cord is cooked to the point of failure. Scott Lacey --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: AFT Failures..Update!
Hey Gary, Don't forget you rocking chair. Take it from me, the ones with the padded seat cushions are the best. Best regards, Ron Pickard rpick...@hypercom.com Gary.McInturff@worldwidep ackets.com To: schan...@frontiernet.net, dmck...@corp.auspex.com, Sent by: emc-p...@majordomo.ieee.org owner-emc-pstc@majordomo.cc: ieee.org Subject: RE: AFT Failures..Update! 10/24/01 05:11 PM Please respond to Gary.McInturff When it gets really really small is it micro-fiche??? Gary PS If you're too young to know what I'm talking about please, please don't tell me I'm already prone to talking afternoon naps wrapped in a shawl. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: EFT Failures..Solved!+ ESD symbol question
MIL JEDEC static warning label examples at: http://www.staticcontrol.com/staticlabels.asp -Original Message- From: Alex McNeil [mailto:alex.mcn...@ingenicofortronic.com] Sent: 25 October 2001 15:05 To: 'emc-p...@majordomo.ieee.org' Subject: EFT Failures..Solved!+ ESD symbol question Hi Group, The problem was an oversensitive Display driver. Replacing this driver solved my problem. It was diagnosed by: 1. Was the problem due to conductive or radiated or both? By using the DC lead, made a small loop, as my noise source with EFT test running, I noticed the problem occurring near the display circuitry. The fault was actually a Display lock whereas I thought it was a keyboard lock (same symptons). I then attached my large ferrite core to the DC cable, several turns, and repeated the test. No problems. I assumed from this that radiated was the problem. 2. What was actually picking up the noise and was the fault the display driver? I assumed the cable connected to my display was picking up this noise and conductively passing it on to the display driver. I could not bypass the problem using caps, functionality started to play up a bit depending on my value of capacitor. It was at this time I noticed that we were using an unfamiliar driver manufacturer! I went to the stores and found the proper part, fitted it and BINGO it now passes up to 3KV I am relatively new to this forum. but I think it a good idea if we all share our problems and diagnostics. I am sure this would be a great help to many of us!! However, for my next question? I want to place a Static Sensitive Area symbol on my product molding, avoiding words, as it will be a worldwide product. The suymbol will be explained in the user guide. Q. Is there a worldwide symbol to denote a Static Sensitive Area or a European one and another North American one or I would need the .bmp file if possible? Kind Regards Alex McNeil Principal Engineer Tel: +44 (0)131 479 8375 Fax: +44 (0)131 479 8321 email: alex.mcn...@ingenicofortronic.com -Original Message- From: Alex McNeil Sent: Tuesday, October 23, 2001 9:44 AM To: 'emc-p...@majordomo.ieee.org' Subject:EFT Failures..Update! Hi Group, THANKS for your very much appreciated responses!! I was in panic mode!! I thought it would be appropriate to let you know the status. My product is a small all plastic enclosure Point if Sale (POS) Class III terminal. It has an external SMPS, Class II, no earth, supplying SELV, 12Vdc 1.5A to my product. The power supply works OK with some of our other products, for EMC. The problem is with my product. I solved the problem at the test house by wrapping a few turns of the DC PSU cable through a Large Ferrite Clamp at the Product input (it did not work so well at the PSU I/P nor O/P). The fix cannot be considered final due to obvious reasons. I am now at my Lab, now the serious diagnostics begin. I have been trying various quick fixes to no avail i.e. Caps, TVS, MOV etc. If you have any further comments feel free to email me. THANKS again to all those who responded with their thoughts. I can tell you they were wide and varied just as you would expect to trying to resolve an EMC problem over the NET!! Best Regards alex.mcn...@ingenicofortronic.com -Original Message- From: Alex McNeil Sent: 22 October 2001 11:23 To: emc-p...@majordomo.ieee.org Subject:EFT Failures..Help! Hi Guys, I am at an EMC test centre today and tomorrow. Unfortunately, my product failed EFT testing on the AC power port at 1KV. This is for various combinations of Line, Neutral and Earth (L, N, E, LN, LE, NE and LNE) My product is Class II, no Earth. It is supplied by an external power supply. This supplies SELV to my product. The power supply manufacturer has stated that his power supply meets EN61000-4-4 for 2KV and has emailed me this report to verify this. Has anyone got a quick solution to my problem so that I can implement here at the EMC test house? Kind Regards Alex McNeil Principal Engineer Tel: +44 (0)131 479 8375 Fax: +44 (0)131 479 8321 email: alex.mcn...@ingenicofortronic.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at:
Re: NEC Question
Anton: Yes, I think you have summed it up nicely. Actually, I have found it very helpful, both for myself and for explaining to others, to consider the sociological background leading to regulations in the US and in Europe. Basically, the US, as I see it for this purpose, is a wild-west capitalist society. Anything goes and the market rules, unless we are told otherwise. The government protecting us from ourselves is a relatively recent development. Europe tends to paternalism and socialism. Government sets the rules and the rules protect the people. Maybe this stems from a history of monarchy and dictatorships. Anyways, the regulation writing business in Europe must certainly represent a significant part of the Gross National Product in EU countries. So, we have examples like EU requiring immunity testing/declaration of products before they are marketed. A consumer has a right to expect that the radio receiver or stereo amplifier or whatever they purchase will be reasonably immune from interference and disruption by unwanted signals. In the US, on the other hand, the FCC makes no requirements for immunity, only for emissions. Here, the marketplace is supposed to operate to eliminate faulty products which have poor immunity. Theory is that consumers will not buy these things. The trouble is that consumers DO buy these things, and that causes endless problems for people (like me) who are involved with radio/TV broadcasting, or other wireless transmitters. Put another way, in the US we have the freedom to buy crap and then complain about it. Back to topic: It has been accurately pointed out that employers/businesses have an obligation, under Federal Law, to use listed products for the safety of their workers. However, just to reiterate, equipment manufacturers have no legal obligation to list products before selling. Again, we see the marketplace. Why would a business buy anything other than a listed product? (The answer is generally ignorance of the requirement). Of course, I could be wrong. Regards, Jack Jacob Z. Schanker, P.E. 65 Crandon Way Rochester, NY 14618 Phone: 716 442 3909 Fax: 716 442 2182 j.schan...@ieee.org - Original Message - From: Nikolassy, Anton anton.nikola...@fmglobal.com To: 'Jacob Schanker' schan...@frontiernet.net; wo...@sensormatic.com; emc-p...@majordomo.ieee.org; mi...@ucentric.com Sent: Thursday, October 25, 2001 10:25 AM Subject: RE: NEC Question | This is a very interesting conversation. Basically you are saying that this | is America. Your allowed to be as liable as you want to be. | | Tony Nikolassy | FMRC | | -Original Message- | From: Jacob Schanker [mailto:schan...@frontiernet.net] | Sent: Wednesday, October 24, 2001 4:38 PM | To: wo...@sensormatic.com; emc-p...@majordomo.ieee.org; | mi...@ucentric.com | Subject: Re: NEC Question | | | | Mike: | | There is no Federal requirement for the manufacturer to have | equipment listed or NRTL approved. The requirements are set by | localities, as Richard Woods clearly points out. | | I can understand that in some companies, the powers-that-be | have little patience with the time and expense of obtaining a | listing. The delay in hitting the market is often more costly | than the approval process itself. | | I say TOUGH. They should have allowed for that in the original | project plan and schedule. There was one, wasn't there? | | If you are having a problem, just ask marketing to agree to | exclude the areas that Richard enumerated from their sales areas. | If it's OK to exclude LA, etc. etc., than listing isn't needed, | legally. | | But the competition may be listing, so not doing so puts you at a | disadvantage. | | I have asked managers to imagine sitting on the witness stand at | a product liability trial, and trying to answer the question, why | didn't you get safety approval from an NRTL? | | When the implications of shortcuts are driven home, most people | see the light. Those that don't need to stick their fingers in an | unlisted light socket. | | Rant concluded, best regards, | | Jack | | Jacob Z. Schanker, P.E. | 65 Crandon Way | Rochester, NY 14618 | Phone: 716 442 3909 | Fax: 716 442 2182 | j.schan...@ieee.org | | - Original Message - | From: wo...@sensormatic.com | To: emc-p...@majordomo.ieee.org | Sent: Wednesday, October 24, 2001 12:23 PM | Subject: RE: NEC Question | | | | | | Mike, regardless of what the NEC says, and it is not very clear | in this | | regard, it is the state, county and city electrical codes and | other local | | regulations that apply. Many jurisdictions have deviations from | the NEC | | and/or have other regulations that require electrical equipment | sold to the | | general public be Listed. I know of the following locations: | Virginia, North | | Carolina, Los Angeles, Counties of Los Angeles and Orange, and | San | | Francisco. I have also heard but cannot confirm that other | locations include | | Oregon, Washington, New York city and Chicago. |
RE: DC voltage ratings
Dave - Perhaps I was misinformed, but it was my understanding that 70V battery was not panEuropean, but is specific to Germany and Austria, and then not necessarily ubiquitous in those countries. I'd appreciate your expanding on this. Regards, Peter L. Tarver, PE Product Safety Manager Sanmina Homologation Services peter.tar...@sanmina.com -Original Message- From: Dave Heald Bruce, snip If you want to ship to Europe, the nominal voltage can be -60Vdc. Here it gets tricky as charging voltages are typically 72Vdc. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: EMC testing above 1GHz
All, FCC Rules, Section 15.33(b): (b) For unintentional radiators: (1) Except as otherwise indicated in paragraphs (b)(2) or (b)(3) of this section, for an unintentional radiator, including a digital device, the spectrum shall be investigated from the lowest radio frequency signal generated or used in the device, without going below the lowest frequency for which a radiated emission limit is specified, up to the frequency shown in the following table: Highest frequency generated or used in the device or on which the device operates orUpper frequency of measurement tunes (MHz) range (MHz) Below 1.705 30 1.705 - 108 1000 108 - 500 2000 500 - 1000 5000 Above 1000 5th harmonic of the highest frequency or 40 GHz, whichever is lower Note that if the highest clock speed is between 500 MHz and 1000 MHz, you test to 5 GHz. Testing to the 5th harmonic (or 40 GHz, whichever is lower) doesn't start until the clock is above 1000 MHz. Ghery S. Pettit Intel -Original Message- From: Dave Heald [mailto:davehe...@mediaone.net] Sent: Thursday, October 25, 2001 1:09 AM To: cecil.gitt...@kodak.com; emc-p...@majordomo.ieee.org Subject: Re: EMC testing above 1GHz Cecil, Measurements above 1GHz are required for the FCC when your highest clock exceeds 108MHz (top end of the FM radio band if anyone is wondering why 108). If the highest clock is between 108-500MHz, the scan goes to 2GHz. If it exceeds 500, the 5th harmonic. In practice, CPU core frequencies count. Note that this does not apply to RF transmitters/receivers or other intentional radiators which have very specific and varied rules. No measurements are currently required by the EU above 1GHz. The FCC carries the limit lines at 960MHz (or thereabouts) all the way to 40GHz. (except for transmitter requirements which vary greatly). One HUGE difference is that the measurements above 1GHz should be made with an average detector. This will typically get you a reduction of between 5-10db (or more!) compared to a peak detector. I had to force this measurement method recently when I was told I had problems at 2.5 or 5 GHz. (of course, the lab took peak measurements and when they took average measurements I was well below the limits and actually passed). Testing is specified at 3 meters but can be reduced as needed for sensitivity (S/N) issues. Best Regards, Dave Heald -Original Message- From: cecil.gitt...@kodak.com [mailto:cecil.gitt...@kodak.com] Sent: Tuesday, October 23, 2001 12:36 PM To: emc-p...@majordomo.ieee.org Subject: EMC testing above 1GHz Importance: High From: Cecil A. Gittens What are the EMC requirements for testing above 1 GHz in an Open Area test site? Cecil --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: Aircrafts
Amund, In the US: you had most of it: RTCA/DO-160D For more info: http://www.rtca.org./ There may be other (additional) airframe specific requirements...which is not at all unusual! Daren A. Nerad EMC Engineer 815.226.6123 -Original Message- From: am...@westin-emission.no [mailto:am...@westin-emission.no] Sent: Thursday, October 25, 2001 7:07 AM To: emc-p...@majordomo.ieee.org Subject: Aircrafts Hi all, Electrical equipment placed inside an aircraft (navigation equipment installed in the cockpit), are they required to fulfil the CE-regulations for use within EU? If yes, which directives apply ? EMC ? LVD ? What about in the US/Canada ? I have a feeling that RO-160D applies. Am I right ? Best regards Amund Westin --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: NEC Question
This is a very interesting conversation. Basically you are saying that this is America. Your allowed to be as liable as you want to be. Tony Nikolassy FMRC -Original Message- From: Jacob Schanker [mailto:schan...@frontiernet.net] Sent: Wednesday, October 24, 2001 4:38 PM To: wo...@sensormatic.com; emc-p...@majordomo.ieee.org; mi...@ucentric.com Subject: Re: NEC Question Mike: There is no Federal requirement for the manufacturer to have equipment listed or NRTL approved. The requirements are set by localities, as Richard Woods clearly points out. I can understand that in some companies, the powers-that-be have little patience with the time and expense of obtaining a listing. The delay in hitting the market is often more costly than the approval process itself. I say TOUGH. They should have allowed for that in the original project plan and schedule. There was one, wasn't there? If you are having a problem, just ask marketing to agree to exclude the areas that Richard enumerated from their sales areas. If it's OK to exclude LA, etc. etc., than listing isn't needed, legally. But the competition may be listing, so not doing so puts you at a disadvantage. I have asked managers to imagine sitting on the witness stand at a product liability trial, and trying to answer the question, why didn't you get safety approval from an NRTL? When the implications of shortcuts are driven home, most people see the light. Those that don't need to stick their fingers in an unlisted light socket. Rant concluded, best regards, Jack Jacob Z. Schanker, P.E. 65 Crandon Way Rochester, NY 14618 Phone: 716 442 3909 Fax: 716 442 2182 j.schan...@ieee.org - Original Message - From: wo...@sensormatic.com To: emc-p...@majordomo.ieee.org Sent: Wednesday, October 24, 2001 12:23 PM Subject: RE: NEC Question | | Mike, regardless of what the NEC says, and it is not very clear in this | regard, it is the state, county and city electrical codes and other local | regulations that apply. Many jurisdictions have deviations from the NEC | and/or have other regulations that require electrical equipment sold to the | general public be Listed. I know of the following locations: Virginia, North | Carolina, Los Angeles, Counties of Los Angeles and Orange, and San | Francisco. I have also heard but cannot confirm that other locations include | Oregon, Washington, New York city and Chicago. | | Richard Woods | Sensormatic Electronics | | | -Original Message- | From: Mike Morrow [mailto:mi...@ucentric.com] | Sent: Wednesday, October 24, 2001 11:52 AM | To: EMC Society | Subject: NEC Question | | | | Can someone point me to a section in the NEC that says a piece of | RESIDENTIAL computer equipment must be listed (NEC definition). Article | 645 which requires a listed piece of equipment appears to apply to a | computer room and not a residence. | | Basically I've been asked where its says a piece of computer equipment must | listed/approved by a NRTL. I'm ignoring the obvious liability implications | should someone get injured for the purposes of this question.. | | Any help is appreciated. | | Mike Morrow | Senior Compliance Engineer | Ucentric Systems, LLC | 978-823-8166 | mi...@ucentric.com | | | --- | This message is from the IEEE EMC Society Product Safety | Technical Committee emc-pstc discussion list. | | Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ | | To cancel your subscription, send mail to: | majord...@ieee.org | with the single line: | unsubscribe emc-pstc | | For help, send mail to the list administrators: | Michael Garretson:pstc_ad...@garretson.org | Dave Healddavehe...@mediaone.net | | For policy questions, send mail to: | Richard Nute: ri...@ieee.org | Jim Bacher: j.bac...@ieee.org | | All emc-pstc postings are archived and searchable on the web at: | No longer online until our new server is brought online and the old | messages are imported into the new server. | | --- | This message is from the IEEE EMC Society Product Safety | Technical Committee emc-pstc discussion list. | | Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ | | To cancel your subscription, send mail to: | majord...@ieee.org | with the single line: | unsubscribe emc-pstc | | For help, send mail to the list administrators: | Michael Garretson:pstc_ad...@garretson.org | Dave Healddavehe...@mediaone.net | | For policy questions, send mail to: | Richard Nute: ri...@ieee.org | Jim Bacher: j.bac...@ieee.org | | All emc-pstc postings are archived and searchable on the web at: | No longer online until our new server is brought online and the old messages are imported into the new server. | --- This message is from the IEEE EMC
Re: Aircrafts
RTCA/DO-160, which abroad is also an ISO document, ISO 7137:1995, Aircraft - Environmental conditions and test procedures for airborne equipment. -- From: am...@westin-emission.no To: emc-p...@majordomo.ieee.org Subject: Aircrafts Date: Thu, Oct 25, 2001, 7:06 AM Hi all, Electrical equipment placed inside an aircraft (navigation equipment installed in the cockpit), are they required to fulfil the CE-regulations for use within EU? If yes, which directives apply ? EMC ? LVD ? What about in the US/Canada ? I have a feeling that RO-160D applies. Am I right ? Best regards Amund Westin --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: skinny power cords.
I agreed completely with Scott. A 6 to 9 foot 18AWG cord will handle well in excess of 20A for a short period of time without starting to smoke (heck, it'll handle close to in excess of 60A for a very very short time without bursting into flames--not that it was a good experience finding this out). Point is, the cordage will handle a fault either indefinitely or long enough for the branch circuit breaker to trip provided you are connected to a 15A or 20A branch circuit. Another data point, you routinely pass more current through the cord when doing the earthing test and that uses more current than the cord is rated. Leave the tester on for awhile and the cord does not really heat up either. What this list needs is a power cord manufacturer or agency safety engineer that does power cords to settle this once and for all! Dan -Original Message- From: Scott Lacey [mailto:sco...@world.std.com] Sent: Wednesday, October 24, 2001 7:43 PM To: Gary McInturff Cc: emc-p...@majordomo.ieee.org Subject: RE: skinny power cords. Gary, I believe the answer is that the power cord rating of 6 or 10 amps is the operating current, at which it will have minimum temperature rise. Under fault conditions it will experience a rather dramatic temperature rise that is still well below the melting temperature of the insulation. The breaker or fuse should clear well before the cord is cooked to the point of failure. Scott Lacey --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
EFT Failures..Solved!+ ESD symbol question
Hi Group, The problem was an oversensitive Display driver. Replacing this driver solved my problem. It was diagnosed by: 1. Was the problem due to conductive or radiated or both? By using the DC lead, made a small loop, as my noise source with EFT test running, I noticed the problem occurring near the display circuitry. The fault was actually a Display lock whereas I thought it was a keyboard lock (same symptons). I then attached my large ferrite core to the DC cable, several turns, and repeated the test. No problems. I assumed from this that radiated was the problem. 2. What was actually picking up the noise and was the fault the display driver? I assumed the cable connected to my display was picking up this noise and conductively passing it on to the display driver. I could not bypass the problem using caps, functionality started to play up a bit depending on my value of capacitor. It was at this time I noticed that we were using an unfamiliar driver manufacturer! I went to the stores and found the proper part, fitted it and BINGO it now passes up to 3KV I am relatively new to this forum. but I think it a good idea if we all share our problems and diagnostics. I am sure this would be a great help to many of us!! However, for my next question? I want to place a Static Sensitive Area symbol on my product molding, avoiding words, as it will be a worldwide product. The suymbol will be explained in the user guide. Q. Is there a worldwide symbol to denote a Static Sensitive Area or a European one and another North American one or I would need the .bmp file if possible? Kind Regards Alex McNeil Principal Engineer Tel: +44 (0)131 479 8375 Fax: +44 (0)131 479 8321 email: alex.mcn...@ingenicofortronic.com -Original Message- From: Alex McNeil Sent: Tuesday, October 23, 2001 9:44 AM To: 'emc-p...@majordomo.ieee.org' Subject:EFT Failures..Update! Hi Group, THANKS for your very much appreciated responses!! I was in panic mode!! I thought it would be appropriate to let you know the status. My product is a small all plastic enclosure Point if Sale (POS) Class III terminal. It has an external SMPS, Class II, no earth, supplying SELV, 12Vdc 1.5A to my product. The power supply works OK with some of our other products, for EMC. The problem is with my product. I solved the problem at the test house by wrapping a few turns of the DC PSU cable through a Large Ferrite Clamp at the Product input (it did not work so well at the PSU I/P nor O/P). The fix cannot be considered final due to obvious reasons. I am now at my Lab, now the serious diagnostics begin. I have been trying various quick fixes to no avail i.e. Caps, TVS, MOV etc. If you have any further comments feel free to email me. THANKS again to all those who responded with their thoughts. I can tell you they were wide and varied just as you would expect to trying to resolve an EMC problem over the NET!! Best Regards alex.mcn...@ingenicofortronic.com -Original Message- From: Alex McNeil Sent: 22 October 2001 11:23 To: emc-p...@majordomo.ieee.org Subject:EFT Failures..Help! Hi Guys, I am at an EMC test centre today and tomorrow. Unfortunately, my product failed EFT testing on the AC power port at 1KV. This is for various combinations of Line, Neutral and Earth (L, N, E, LN, LE, NE and LNE) My product is Class II, no Earth. It is supplied by an external power supply. This supplies SELV to my product. The power supply manufacturer has stated that his power supply meets EN61000-4-4 for 2KV and has emailed me this report to verify this. Has anyone got a quick solution to my problem so that I can implement here at the EMC test house? Kind Regards Alex McNeil Principal Engineer Tel: +44 (0)131 479 8375 Fax: +44 (0)131 479 8321 email: alex.mcn...@ingenicofortronic.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy
RE: NEC Question BUT REMEMBER OSHA
Just to ensure that I have my understanding right - if the equipment is used where OSHA applies then it must be approved by a third party like UL If it is domestic then it does not (in most states. Comments please. AND, does anyone have a list of States where certification is mandated? Best regards Gregg --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Aircrafts
Hi all, Electrical equipment placed inside an aircraft (navigation equipment installed in the cockpit), are they required to fulfil the CE-regulations for use within EU? If yes, which directives apply ? EMC ? LVD ? What about in the US/Canada ? I have a feeling that RO-160D applies. Am I right ? Best regards Amund Westin --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: Fish paper
Of course; after its namesake, fish paper could be expected to be hygroscopic. Or maybe someone just called it fish paper for the halibut. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: Fish paper
We have found that some of these vulcanised paper cards can be hydroscopic and result in leakage problems. A modern alternative is material such as Dupont Nomex 410. Chris -Original Message- From: Price, Ed [mailto:ed.pr...@cubic.com] Sent: 25 October 2001 04:05 To: 'EMC-PSTC List' Subject: Fish paper Here's an interesting reference to fish paper, from the Rane Audio Reference site: http://www.rane.com/digi-dic.html fishpaper An insulating paper, often fiber- or oilcloth-like, used in the construction of transformers and coils. [Historical Note: EP Coughlin of LMC Plasticsource http://www.lmcplasticsource.com/ writes: Although my roots go back in fibre to 1959 I have never seen any hard copy evidence noting the origin of the name 'fishpaper.' My initial experience in the fibre industry was with Taylor Fibre Company and the owner claimed roots back to Thomas Taylor of England who is credited with 'inventing' vulcanized fibre. Original patent was in Great Britain in 1859 and Thomas Taylor received a US patent in 1872 titled 'Improvements in the treatment of paper and paper-pulp.' The major use for vulcanized fibre eventually was in the electrical insulation field but, obviously, requirements for same did not exist in 1859. Although anecdotal, John Taylor (owner/founder of The Taylor Fibre Company) claimed that vulcanized fibre's initial use was in England's fish markets as table / bin liners. The resistance to fish oil and tearing of vulcanized fibre makes this a very plausible story.] Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: DC voltage ratings
Bruce, There are two answers to this question. No, you can just rate it at -48Vdc which should be good for the US but is questionable in the EU at this point. At -48Vdc (and even during charging @ 60V peak), it is a SELV circuit. Some companies label for the charging voltages, but this should be unnecessary due to the SELV reasons above. (and labeling at -60V may cause you problems due to the ±% that you may be held to by some NRTL's or NRTL engineers. They MIGHT say you exceed the SELV range. Why risk it?) OR If you want to ship to Europe, the nominal voltage can be -60Vdc. Here it gets tricky as charging voltages are typically 72Vdc. Most NRTL's testing to the new UL60950 will treat DC input voltages at these levels as TNV-2, which is a lot better for design reasons than treating your input circuit as a hazardous voltage circuit. If shipping to Europe, it may also help to leave your label rating at (range maximum) -60Vdc and evaluate for TNV-2 inputs anyway. There may be some loopholes to allow reduced/eliminated production line testing (which is never a bad thing - realistically for this type of application anyway) and you still proved your system safe at TNV-2 level DC input voltages. This all could depend on your NRTL of course (and possibly your engineer within the NRTL). I have also heard of people leaving the rating at -48Vdc and selling it to Europe anyway. I don't fully understand the ethics or legality involved, but the real world input voltages are low enough that they are unlikely enough to cause a safety issue so some European telcos will install the -48V rated equipment anyway as long as they determine it will work reliably in their networks. AS A DISCLAIMER, I DO NOT ADVOCATE THIS PATH, I just wanted to throw it in as an FYI. Hope this helps and does not confuse the issue too much, Dave Heald Bruce Touzel (EUD) wrote: Does 48Vdc powered telecom equipment need to have a min and max input rating ? I have heard of 60Vdc max input, maybe because of charging voltage can peak to this level, or maybe because some countries operate at this level ? thanks Bruce Ericsson Datacom Inc. IP Network Edge Access (IPNEA) 70 Castilian Drive Santa Barbara, CA Phone/cell (805) 562-6571 Fax (805) 685-4465 bruce.tou...@ericsson.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: AFT Failures..Update!
When it gets really really small is it micro-fiche??? Gary PS If you're too young to know what I'm talking about please, please don't tell me I'm already prone to talking afternoon naps wrapped in a shawl. -Original Message- From: Jacob Schanker [mailto:schan...@frontiernet.net] Sent: Wednesday, October 24, 2001 12:18 PM To: Doug McKean; EMC-PSTC Discussion Group Subject: Re: EFT Failures..Update! Excuse a slightly peripheral question. I always called it (an oily sort of brownish paper) Fish paper. I assumed the name came from the use of fish oil to prepare it in the 1800's. I see you are referring to it (is it the same thing?) as fische paper. Is that what it is sold as? Was it invented by Mr. Frederick Fische? How about a musical variant - Phish paper. :) Jack Jacob Z. Schanker, P.E. 65 Crandon Way Rochester, NY 14618 Phone: 716 442 3909 Fax: 716 442 2182 j.schan...@ieee.org - Original Message - From: Doug McKean dmck...@corp.auspex.com To: EMC-PSTC Discussion Group emc-p...@majordomo.ieee.org Sent: Tuesday, October 23, 2001 1:14 PM Subject: Re: EFT Failures..Update! | | Discussion forum problems are challenging problems to | say the least. | | One thing you might want to try is to add a ground plane | into the bottom of the case with a piece of copper plate | or foil. Connect the plate (or foil) to the return side of the | power leads. Then, if you've got some fische paper (heck | even masking tape and several sheets of printer paper will | work in a moment of crisis), use that to insulate the plate | from the bottom of the board. And get the plate as close | as possible to the bottom of the board. | | But to really understand what's going on, you'd probably | have to set up something with current probes or differential | probes to follow the effect of the pulse. | | Most likely what's happening is the power supply is | acting as the source of the pulse out to your product | (obvious but bear with me) and the power leads and | your product are simply acting as an arm of a distorted | dipole, i.e., low impedance source (the power supply), | high impedance end of the arm (your product). | | Think for a moment of the power supply is the source | of a dipole and the two cables from it, the ac input cord | and the power output cord are the arms of a dipole. | | You're whole effort here is to disrupt that construction. | | Thus, it is possible that by adding ferrites to the product | end of the power leads, you could actually enhance this | dipole effect. This is possibly why adding ferrites to the | power cord to your product may not be working. In | other words, the ferrite increases the impedance of | the end of the dipole arm (your product) even higher. | | This has been demonstrated time and again by | Doug Smith in his many demonstrations. | | The effect of the plate *hopefully* disrupts this | pseudo-dipole construction. It may, it may not. | | The position of ferrites can be important. If you're | in a real bind, then you might want to simply load up | the entire construction with ferrites all over the place | to see if that works. Start removing ferrites until you | get a minimal setup that works and go from there. | The positions of the remaining ferrites in a working | setup can sometimes telll you what's going on in | a setup that's modelled after a dipole. | | Good luck ... | | Regards, Doug McKean | | | | --- | This message is from the IEEE EMC Society Product Safety | Technical Committee emc-pstc discussion list. | | Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ | | To cancel your subscription, send mail to: | majord...@ieee.org | with the single line: | unsubscribe emc-pstc | | For help, send mail to the list administrators: | Michael Garretson:pstc_ad...@garretson.org | Dave Healddavehe...@mediaone.net | | For policy questions, send mail to: | Richard Nute: ri...@ieee.org | Jim Bacher: j.bac...@ieee.org | | All emc-pstc postings are archived and searchable on the web at: | No longer online until our new server is brought online and the old messages are imported into the new server. | --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old
RE: skinny power cords.
I'll join the speculation... I think it is also based on the likelihood of undetected damage to the cord leading to a situation. The cord lengths are limited by standards, they are jacketed with materials designed to withstand some abuse, the condition is easily (albeit rarely) inspected by the user, they are not supposed to be physically attached to the wall (so no fear of damage by a metal cable clamp for example), and so on. The wiring in your walls, by comparison, may be more at risk, since it can't be inspected, it is stapled to the studs, and you're always drilling or pounding nails into walls having no idea whether or not there is wiring behind the drywall. Regards, Jim Eichner, P.Eng. Manager, Engineering Services Xantrex Technology Inc. Mobile Power web: www.xantrex.com http://www.xantrex.com Any opinions expressed are those of my invisible friend, who really exists, and frequently has gas. Honest. -Original Message- From: Rich Nute [mailto:ri...@sdd.hp.com] Sent: Wednesday, October 24, 2001 12:21 PM To: gary.mcintu...@worldwidepackets.com Cc: emc-p...@ieee.org Subject: Re: skinny power cords. Hi Gary: Somewhere in my past, I've heard the rationale for this conundrum. I'm just guessing here. Power cords and similar mains devices are sized based on rated load, and are not sized based on fault-condition load. The requirement should be that, under fault conditions, the device is capable of withstanding the fault until the overcurrent device operates without igniting or otherwise causing a hazard. It can get hot; indeed, it can exceed rated temperature under the fault, and it can fail, but it should not ignite or otherwise cause a hazardous condition. A power cord is supposed to be sufficiently robust as to withstand the rigors of use. There are different degrees of robustness according to use. In other words, the power cord itself is not expected to fail under normal conditions of use. So, the power cord should only be subject to load faults. Since the load is protected against faults, the fault-protection in the load also provides fault-protection for the power cord. Best regards, Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
