Re: AW: Define Continuous DC Voltage

2001-11-14 Thread Rich Nute
Hi John: SELV can protect under single fault conditions. BUT, as I tried to explain, under some conditions, it can allow a single fault *to persist undetected*, until eventually a second, unrelated fault occurs which then results in a serious hazard. This is a problem of the

Re: Define Continuous DC Voltage

2001-11-14 Thread Rich Nute
Hi John: Tetanus is a disease caused by a bacillus. Muscles spasm is tetany. Not according to my (American) dictionary. Tetanus has two definitions. The first is the disease or the bacterium that causes the disease. The second is a prolonged contraction of a muscle resulting from

Re: [Fwd: User Warning Signal Words]

2001-11-13 Thread Rich Nute
According to ANSI Z35.4 the following definitions are provided: DANGER - Indicates an imminently hazardous situation which, if not avoided will result in death or serious injury. This signal word is to be limited to the most extreme situations. WARNING -

Re: HiPot testing of DC mains powered products

2001-11-13 Thread Rich Nute
Hi Chris: I wonder why you need to hi-pot test a SELV-powered product? (I presume your external 48-volt dc source is SELV.) We make products intended for connection to an external dc source (SELV). We have never been required to perform a hi-pot test on such products. The

Re: CLASS 11(DOUBLE INSULATED) 2/3-CORE CABLE

2001-11-13 Thread Rich Nute
Hi John: No; France and Norway have 'IT' systems, in which grounding is only to prevent static charge build-up; the neutral is grounded through an impedance at the sub-station. AIUI, this is used in mountainous districts where ground paths are long and of low conductivity. There

Re: Define Continuous DC Voltage

2001-11-13 Thread Rich Nute
Hi Dan: Does anyone know what voltage is used in electric chairs? Just Curious. I'm sorry you asked. The electric chair is one of the more barbarous methods of execution. The voltage is a function of time, and varies with the execution authority. The voltage is in the range of

Re: [Fwd: User Warning Signal Words]

2001-11-13 Thread Rich Nute
Hi John: I feel the authors of these definitions neither consulted a dictionary nor the users of warnings. I'm sure that you are right, but what is the alternative to using existing words but with special definitions that make their meanings more precise? If you solve

Re: Define Continuous DC Voltage

2001-11-13 Thread Rich Nute
Hi Gregg: There was also a very good (but short) article by Tektronix in the 70's called The Lethal Current. It concluded that currents between 100 mA and 3 Amps were more lethal that currents of more than 3 Amps because those high currents tended to 'restart' the heart.

Re: Define Continuous DC Voltage

2001-11-13 Thread Rich Nute
Hi Chris: I'll attempt to answer the question as to the effect of ac and dc current on the body (the hazard). The discussion is in regard to three waveforms: 1) ac sinusoidal -- 50-60 Hz. 2) dc 3) dc interrupted (equal on and off times) up to 200 Hz. Each has a different

Re: Safety Critical etc - the future

2001-11-12 Thread Rich Nute
Hi Peter: As I have already written, I feel that safety-critical component as well as safety-related component are terms that require more consideration than is necessary. Basically, as I understand what you have said, a safety- critical component is one where its failure creates a

Re: Safety Critical Input Summary

2001-11-01 Thread Rich Nute
Hi Lauren: There are different definitions for safety-critical component based on the different needs for identification of such components. I'd like to list a few, and then offer yet a different definition of a safety-critical component. 1. A safety-critical component is a component

Re: skinny power cords.

2001-10-25 Thread Rich Nute
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

Re: skinny power cords.

2001-10-25 Thread Rich Nute
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

Re: NEC Question BUT REMEMBER OSHA

2001-10-25 Thread Rich Nute
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.

Re: skinny power cords.

2001-10-25 Thread Rich Nute
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

Re: NEC Question BUT REMEMBER OSHA

2001-10-25 Thread Rich Nute
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

Re: skinny power cords.

2001-10-24 Thread Rich Nute
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

Re: NEC Question

2001-10-24 Thread Rich Nute
Hi Mike: 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. In terms of the NEC, a

Re: Light Emission from Professional Photography Flashes

2001-10-19 Thread Rich Nute
Hi Peter: Any limitations/requirements for amount of light emitted from professional photography flashes? Any UL, IEC or European standards which specify limitations? I know how many you like being photographed - but imagine what harm one of these flashes can cause to your

Re: UL - marking - gentle warning not to extrapolate.

2001-10-18 Thread Rich Nute
Hi Peter: Thanks for sending the UL letter and UL Listing Mark page. I stand corrected. For Information Technology Equipment, UL's letter of March 31, 1995, authorizes the optional use of the file number as the control number. Apparently, this option is not available for non-ITE products.

Re: Printable calendar for 2002

2001-10-18 Thread Rich Nute
Hi Robert: I got two NAV (Norton Antivirus) msgs back from the ieee.org that said my attachment had a virus in it. If so, please let me know, because there is nothing but text files (that I know of) and a simple batch program in that attachment. The IEEE listserver checks

Re: UL - marking - gentle warning not to extrapolate.

2001-10-18 Thread Rich Nute
Hi Gregg: The File number 'may' be used on things like cable (it is common to see UL and CSA file numbers) and other components - Control numbers (I forget the correct terminology) is required on some UR components but not all Listed products. UL Listed wire: According to

Re: UL - marking - gentle warning not to extrapolate.

2001-10-18 Thread Rich Nute
Hi Ron: 1. UL in a circle (the famous UL Listing mark symbol), 2. The word LISTED in capital letters, 3. The assigned control number*, and 4. Product identity (e.g., NWGQ, I.T.E., etc.) * The assigned control number is a designation that UL assigns to a manufacturer, or

Re: UL - marking - gentle warning not to extrapolate.

2001-10-17 Thread Rich Nute
Hi Chris: Does the file number need to be on the label? Can the manufacturer leave the file number off of the label and simply put a generic UL (or CSA) mark on the product along with their nameplate identifying the manufacturer, model and serial number? In my response to

Re: Power Plugs

2001-10-07 Thread Rich Nute
Hi John: Not to Continental countries, AIUI, because rewirable plugs are not available (maybe in Denmark still). Oh? In April, 2001, I bought a re-wirable plug in Grenoble, France, at a major chain store. They had a nice selection! Best regards, Rich

Re: agency seminar quality

2001-09-28 Thread Rich Nute
Hi Brian: I have, w/in previous 6 mos, attended seminars offered by (2) agencies. I learned much from both, and appreciated being able to talk to the gurus. But upon review of seminar notes and manuals from previous Product Safety Engineers, it would seem that issued

Generic safety standard

2001-09-27 Thread Rich Nute
Hi Peter: I agree with you with your statement rather than address products, safety standards need to address hazards. However, the hazard standards must be made taking into consideration the environment in which the product is used light industry, heavy industry, medical,

Re: Applying the appropriate ENs

2001-09-27 Thread Rich Nute
Hi Gregg: Consider the number of PRODUCT standards written - these reflect the accepted degree of protection (Operator or User) for each product under specified operating conditions and accepted uses. I invite consideration of INJURY, and the means by which an injury can occur from

Generic safety standards

2001-09-27 Thread Rich Nute
Hi John: But the standards for these products have to be written by experts in the design of these products - non-experts would not know the problems that can arise. To produce generic safety standards, experts in the design of ALL products would be required. These exist only on

Re: Applying the appropriate ENs

2001-09-26 Thread Rich Nute
It is the primary end use of the product that dictates the standard(s) required. Unfortunately, this archaic and provincial view on the part of standards organizations that standards should be per product has created problems that most of us would like to avoid. Consider product

Re: Photo Sensitive Epilepsy. (PSE)

2001-09-25 Thread Rich Nute
Hi John C. and John W.: Would anyone have any guidelines on how to design computer graphics in such a way to avoid inducing Photo Sensitive Epilepsy in anyone who suffers from that complaint ? .. .. .. A web search for 'epilepsy AND photosensitivity' will probably give you

Re: Limited Current

2001-09-18 Thread Rich Nute
Hi John: Are you sure that you can get appreciable X-radiation at 8 kV? In the days of monochrome TV with 9 and 12 inch tubes running at 8 kV, we never bothered about X rays, but projection sets running at 25 kV were known as a radiation hazard. Maybe tolerance levels have been

Re: UL requirement for driver

2001-09-18 Thread Rich Nute
[quote]Hi, I am basically an EMC guy and do not know much about UL requirements. I would like to know if there are any UL requirements for a driver with output voltage swing of +/- 30V peak-to-peak. The RMS voltage will be much smaller, and the power will be less than 0.5 watt. The driver is

Re: Limited Current

2001-09-17 Thread Rich Nute
Hi Rick: I am working on a project that delivers 8 KV to 1 CRTs mounted on a helmet mounted display. The output of the high voltage supply is limited to 100uA and assuming that the supply complies with paragraph 2.4 (2.4.4 in particular) Paragraph 2.4.1 states that: Note that

RE: Need electrical characteristics of epidermis (skin)

2001-09-14 Thread Rich Nute
Sorry to post here but am running into a brick wall at trying to find out something as simple as the resistivity and dielectric constant for skin! Does anybody have a source? Need quick, please. - Robert - Hi Robert: The skin resistivity and dielectric

Re: UL vs CSA (IT product)

2001-09-10 Thread Rich Nute
Hi Amund: UL and/or CSA certification are mandatory within the electrical safety area, to have access to the US and Canadian marked. Right ? Yes -- sort of. Safety certification of IT equipment is mandatory in both Canada and the USA. However, both countries accept safety

Re: Component and material traceability

2001-09-07 Thread Rich Nute
Hi Jim: There are a number of ways to prove traceability of bulk-labelled components, i.e., components that are not indivually marked. - unmarked components - may not be able to tell mfr and cat. no, let alone agency status and ratings These are really bulk-labelled components. If

Re: UL approval IT equipment

2001-09-07 Thread Rich Nute
Hi Amund: We want our IT product to be UL approved. We purchase a modified power supply (PS) which is not UL appoved. The original PS is UL approved. The only difference in the PS is the value of one resistor which means that we now can take 2.3A/28VDC out instead of

Re: Sound Engineering Practice

2001-09-06 Thread Rich Nute
Hi Lauren: Does anyone have a practical or authoritative definition of Sound Engineering Practice?. The key word is sound. Presumably we all know what engineering practice is. I checked Merriam-Webster's on-line Collegiate Dictionary and found the following definition. The 3rd

Re: current carrying conductors

2001-08-18 Thread Rich Nute
Hi Richard: A number of good comments have been made. I'm not sure anyone covered the fact that two wires make a bundle, and therefore each single in that bundle must be derated. So, a single 10 AWG is good for 32 amps at 20 C. But, two 10 AWG wires in the same bundle are only good for

Re: virus targeting list?

2001-08-18 Thread Rich Nute
Hi George and Ravinder: We really like to discourage off-topic discussions, including virus warnings. Here are some points I'd like to make: 1. The IEEE majordomo listserver includes virus checking (for known viruses) of all messages posted to the listserver. IEEE virus

Re: CE test suite for computers

2001-08-17 Thread Rich Nute
Hi Ghery: Also EN 61000-3-3 needs to be considered. Useless standards, if you ask me. Agreed! EN 61000-3-2 is driven by Euro power distributors who don't want to correct for non-linear loads. (But who have no quarrel with correcting for phase angle.) I don't understand the drive for

Re: Hot Chassis?

2001-08-14 Thread Rich Nute
Hi Dan: with a three prong NA cord set. I have found that if I bypass the earth ground plug I can measure a 80 VAC potential from my chassis to earth This is normal. Consider the circuit: L o- 120 V rms | | 2200 pf

emc-pstc archive and RCIC

2001-08-06 Thread Rich Nute
The RCIC archive for emc-pstc messages will be shut down, permanently, some time this week. The archive itself is preserved. We are working on a new web site for the archive. We expect to announce the new web site along with a number of other web-based features some time this Fall. We

TV nostalgia

2001-08-03 Thread Rich Nute
Okay... more nostalgia and a bit on safety back in those days... so that we don't stray too far from the subject matter of this forum. My first TV was a Motorola 7-inch round in a Bakelite cabinet. The speaker was the same size as the CRT. My second was the famous RCA 10-inch round chassis

Re: Creepage dist. for more than 1000V ?

2001-08-02 Thread Rich Nute
Hi Terry: I don't recall the Sony but do recall the Philco and that Zenith held out with the `hand wired' chassis. Now that you mention it... I do indeed recall that campaign. But, I did not -- then -- realize the context. Today, looking back, that campaign was really quite absurd!

Re: Creepage dist. for more than 1000V ?

2001-08-02 Thread Rich Nute
I saw the first PCB show up in TVs, Would you care to put a date on that? You can't change the facts. So yes! In the Middle to late 50's. :-) Having been a TV serviceman until 1960 (end of my college days), I saw no PCBs in USA TVs. I do recall PCBs in circa 1963 TVs.

Re: Class III anomoly

2001-08-01 Thread Rich Nute
Hi John: This came up at IEC TC74 WG8 and was the object of several proposals. We could come to no agreement about whether Class III included TNV, earth connections, internally generated voltages of assorted energies, etc., so we dropped the subject. It plays no

Re: Mains fusing

2001-08-01 Thread Rich Nute
Hi Kyle: I have a new product that includes an off the shelf UPS that is rated for 230V ac operation and has an internal single pole circuit breaker on the mains inlet. We want to target this product world-wide. The UPS presently is CB and certified to EN60950 european only.

Re: Vibration Perceived as Shock

2001-07-25 Thread Rich Nute
Hi Tania and Richard: When you find out any papers on this subject, please share with us. I stumbled across a short, authoritative discussion about why a mechanical vibration can feel like a small electric shock. Actually, it is the other way around. At small voltages and currents,

Re: IEC60417 Symbols for Power Over the LAN Back-Up Source of Supply

2001-07-24 Thread Rich Nute
Hi Peter: For back-up power supply connections to a device which has means for connection to a floating dc input of 44-57 Vdc / 15 A max (to serve as back-up source for the internal power over LAN source), what is the proper way of marking with symbols to IEC60417 Does the

Re: You won't believe this ... Well, maybe you will.

2001-06-19 Thread Rich Nute
Hi Doug: done, the entire safety approval reduced to a simple cfm rating fan for a chip both on the secondary side of the power supply. The issue for me is: What is the safety requirement that requires cfm (I presume a minimum cfm)? Reading between the lines... The fan

Dithering

2001-06-15 Thread Rich Nute
Hi Ken: In conclusion, dithering will help you meet a test requirement, but it might not actually reduce potential interferences. I have come to the same qualitative conclusion, and the EMC experts with whom I have discussed this concept agree. But, is there any evidence, anecdotal,

please accept my Apology

2001-06-12 Thread Rich Nute
EMC Forum, I apologize for the Shameless Advertisement on the Technocal Forum. It was not my intention to break any rules of the IEEE society. I have been a member for quite some time and thought that I have seen similar FREE OPEN HOUSE events in the past. I have learned much from this

Re: Secondary Grounding

2001-06-01 Thread Rich Nute
Hi Chris: Consider a product with two, independent protective grounding/earthing connections. This may be by means of two power cords (as is done for uptime reliablity by employing parallel power supplies) or by means of one power cord and a separate ground connection (as, for example, by

Re: UL Mark

2001-06-01 Thread Rich Nute
Hi Dave: Can anybody tell me where it is defined at what point in production it is permissible to apply the UL mark? Can it only be done after the hi-pot has passed? Or is it OK to have the label applied before the test as long as the units are clearly marked as having failed

HP Product Safety jobs in Boise, ID, and Vancouver, WA

2001-05-23 Thread Rich Nute
Hewlett-Packard has 3 product safety jobs available. Requisition Position Location number --- - 711022Safety EngineerVancouver, Washington 713386Regs/Safety Engineer Vancouver, Washington 713501

Re: Production Line Test Requirements - Medical Devices

2001-05-21 Thread Rich Nute
Hi John: Because continuity at low current does not ensure that the protective circuit will carry a large fault current - it might be 'hanging on by one strand'. Yes, for one strand. No, for five strands. Some years ago, I did some experiments on what problems the 25-amp test

Re: US Mains Plug/Earthing

2001-05-18 Thread Rich Nute
Hi Tania: I hate to call you an old-timer;-- I would rather state that you might be thinking of UL 114 and UL478 standards that are no longer in force. B ut I don't believe that even they allowed a willy-nilly change from groun ded equipment to one that is ungrounded, unless

Re: US Mains Plug/Earthing

2001-05-17 Thread Rich Nute
Do EU manufacturers have to fit a suitable mains plug to appliances when exporting to USA?... or can it be supplied without a plug, putting the requirement on the user to follow the instructions - in my case, stating that a grounding plug must be used ? There are two answers:

Safety of CD discs at high read rates.

2001-05-17 Thread Rich Nute
Here's a web site that reports that CDs will come apart if attempted to be read at 64x. http://www.qedata.se/en-cdrom.htm There is no data as to what happens in a real CD drive. Enjoy! Rich --- This message is from the IEEE EMC Society

Re: US Mains Plug/Earthing

2001-05-16 Thread Rich Nute
I am in the UK, a customer in USA wants us to fit 2 pin mains plugs to the Class 1 appliances he is going to be buying from us. He is very firm that there are no regulations in US that requires this to be so. Is that true? The simple answer is that there is no regulation

Re: 120V appliance on 240V supply

2001-05-14 Thread Rich Nute
Hi Ravinder: I am interested in knowing if a 120V, 60Hz microwave oven can be safely used on a 240V, 50Hz mains supply with a step-down transformer. In essence, you are asking if a microwave oven rated for 60 Hz will operate safely at 50 Hz. I would guess that the microwave oven uses

EMC-PSTC survey results

2001-05-11 Thread Rich Nute
A summary of the emc-pstc survey results is now available on the Product Safety Newsletter web site: http://www.ewh.ieee.org/soc/emcs/pstc/ The results are in a 16k pdf file. If you are unable to access our web site, send e-mail to either Jim or Rich and we will be happy to send you

Re: UL 1419 Earth Leakage

2001-05-07 Thread Rich Nute
Hell Duncan: - Would they use S1 when leakage testing our type of equipment? Your equipment is cord-connected equipment, not direct-plug-in equipment. Therefore, S1 is not used when testing leakage current from your equipment. - What is the definition of 'direct plug in' (it is

Reminder: IEEE emc-pstc subscriber survey

2001-04-27 Thread Rich Nute
If you haven't filled out the IEEE emc-pstc survey, please do so no later than 05 May. Please go to this URL for the survey: http://www.ewh.ieee.org/soc/emcs/pstc/Survey/ At my last check, only about 20% of our subscribers have completed the survey. I'd really like to get 80% or

Re: EN60950 (UL1950, IEC 60950) On off switch marking.

2001-04-27 Thread Rich Nute
Hi Rick: There are three issues which we must address: 1. The safety function of the switch. 2. The safety function of all-pole disconnect versus one-pole disconnect. 3. The marking of the function of the switch. * The safety function of a disconnect device (for which a

Re: Dielectric Voltage-Withstand Test

2001-04-24 Thread Rich Nute
Dan Kinney asks about pole-to-pole hi-pot testing. The hi-pot test determines that the product's insulation (both air and solid) is sufficient to withstand the normally-occuring transient over- voltages on a power line. Transient over-voltages are both differential-mode (pole-to-pole) and

Re: 2. 4 GHz cordless telephone, question of general interest

2001-04-20 Thread Rich Nute
Hi Ken: Here are some quotes: http://www.eskimo.com/~billb/weird/microexp.html#demo: Q: Aren't these ovens tuned to a special frequency so they only heat water? A: No. The usual operating frequency of a microwave oven is nowhere near the resonant frequency of water, and the

Re: SELV vs ELV

2001-04-19 Thread Rich Nute
Hi Dave: the UL report for the PSU, it states that the output is ELV, not SELV, because of the connector interfacing the modules to the rack. I don't see how a connector makes the difference between ELV and SELV. The terms ELV and SELV imply the energy is derived from a hazardous

Re: Flicker problem

2001-03-14 Thread Rich Nute
expressed as 'dmax', the maximum relative voltage change, measured as an r.m.s. value over the worst half-cycle, starting from the zero-crossing. While I suppose there are sophisticated oscilloscopes that will make this measurement at the touch of a button, I wonder how many colleagues

Re: Repeat Postings

2001-03-13 Thread Rich Nute
Hi George and all: Yes, we are having some listserver multiple send problems. Please bear with us while we fix the problem. Please direct all such questions to me or to one of our admins at the bottom of the message. Even your message could get sent multiple times, so we want to keep the

Chris' humorous story is true!

2001-03-12 Thread Rich Nute
Hello from San Diego: One of my colleagues has added material of interest to one of Chris Allen's humorous stories. Best regards, Rich This is actually a true story (with some adjustment). It happened at a Ford plant back in the 1930's (which makes the $50K fee all the more

Re: Harmonics -- WSJ opinion.

2001-02-27 Thread Rich Nute
Hi John: Of course, no one has shown that unacceptable overheating will actually occur. Do you have any more such gems to contribute? What do you think happens to the total current through a capacitor when the applied voltage contains harmonics? What happens to the I^2R

Re: Harmonics -- WSJ opinion.

2001-02-26 Thread Rich Nute
Hi John: I must admit to several motives for posting my message regarding the WSJ-E opinion article. 1. I wanted our subscribers to know that the issue rated comment in the WSJ-E, a high- level, respected newspaper. 2. I wanted our subscribers to know that the technical

Harmonics -- WSJ opinion.

2001-02-26 Thread Rich Nute
With thanks to Ed Jones... On Thusday, February 22, The Wall Street Journal Europe published an interesting opinion on the harmonic current emissions standard. The opinion is by Rob Hunter, a lawyer and Chairman of the Centre for the New Europe, a Brussels-based think tank. Mr. Hunter is

Re: FLAME RATING OF STANDOFFS

2001-02-20 Thread Rich Nute
Hi Kaz: Answering the question, what's the safety concern, is a reverse-engineering process with respect to the various requirements contained in the standard. Applying the requirements of the standard to the specific construction may involve or even require interpretetation of the

Re: FLAME RATING OF STANDOFFS

2001-02-20 Thread Rich Nute
Hi Kazimier and Terry: Kazimier suggests asking the question: what's the safety concern Unfortunately, safety certification houses do not have the option of accepting products based on the answer to this question. A safety certification house certifies a product to a standard.

Virus and what we're doing.

2001-02-13 Thread Rich Nute
It appears that one of our subscribers has been subjected to a virus. The IEEE listserver stripped the virus from the posted messages, so the virus was not passed on to you and our other subscribers. It appears that the worst that has happened is that duplicate messages were posted to the

Re: Unreliability of earthing/groiunding

2001-01-31 Thread Rich Nute
Hi Bob, Pete, Gert: A common equipotential environment is the goal. It's unfortunate we ever started with the terms earthing or grounding. Absolutely! Furthermore, the equipotential environment can be, and in some cases is, largely independent of whether the protective conductor is

Would you help run the IEEE listserver?

2001-01-29 Thread Rich Nute
that come up. If you find this listserver to be of value to you, and you can spare some time each day to help, and you have a high-speed connection to the internet, please consider volunteering for 2 years to help keep this service running. Please contact me or Jim Bacher. Best regards, Rich Nute ri

Re: Product Marking - new twist

2001-01-26 Thread Rich Nute
Hi Andy: Is it possible that a piece of equipment with an NRTL listing can be disconnected by a local electrical inspector/electrician enforcing the NEC because that paticular NRTL is not approved in their jurisdiction? Yes. Please recognize: NRTL is an OSHA program governing

Re: Product Marking - new twist

2001-01-25 Thread Rich Nute
Hi Chris: For instance, one of the messages says that the NEC gives an electrician the right to unplug an un-NRTL-marked piece of equipment. Another message states that the NRTL's mark is the proof of product safety. NRTL is a designation issued by OSHA. Approved is a

Re: Product Marking

2001-01-24 Thread Rich Nute
Hi Courtland: I have a question concerning labeling a product. If we go to a NRTL and get Safety testing performed, we typically put the Safety logo (UL for example) on the product label. Our marketing people have a problem with having different logo's. They would like to

Re: Client Presence During Testing

2001-01-24 Thread Rich Nute
Hi Kate: a) Do they allow presence in lab (technical area) itself ? If not, then where are clients who are at the lab normally placed? Depends on whether the lab is testing a competitor's products. If not, then I can usually observe the testing. If I can't go into the lab to

Re: Color or marking of buttons - safety question

2001-01-19 Thread Rich Nute
Hi Paul: However, to release the interlock, a PAUSE or STOP button is pressed which allows the instrument to stop in an orderly way and then release the cover. Best as I can tell, a red pushbutton, with PAUSE or STOP legend and the ! in a triangle (to refer the operator back

Administrator's comments: F-Squared labs

2001-01-10 Thread Rich Nute
I'd like to clear up a few things about the situation regarding F-Squared Labs. 1. F-Squared Labs did NOT post its message to the IEEE listserver. It appeared in our distribution because one of our subscribers inadvertantly included it as an attachment to his posting.

Re: FW: power factor

2001-01-09 Thread Rich Nute
Hi John: Can you tell me the typical power consumption of a desktop VDU. For example a Sun workstation VDU rating plate indicates 220-230 V 1.5A. Rather than assume or guess a power factor value, what would the power reading (Watts) be approximately at 220V for nornal

Re: EN61000-3-2 / EN61000-3-3 (Again)

2001-01-09 Thread Rich Nute
Hi Doug: There are four observation periods listed in para 6.2.4 of A14 (table Z1), I assume that I only have to pick the one that suitably qualifies my equipment's operation, or must I apply each one to determine the best period of observation? From my reading of prA14 (I

Re: EN61000-3-2 / EN61000-3-3 (Again)

2001-01-03 Thread Rich Nute
Hi Craig: Be careful: EN61000-3-2 - Applies only to products with input power higher than 75W. Per paragraph 7.4 of the standard, no limits apply for equipment with an active input power up to and including 75W. No. The standard does NOT say that it applies only to products with input

Re: Spacings Issue

2000-12-27 Thread Rich Nute
Hi Ed: First of all the floating secondary ground (if not connected directly to earth) should be treated as part of the secondary circuit which in many cases will require reinforced insulation to the primary circuit according to the working voltage measured. There are two

Re: Spacings Issue

2000-12-27 Thread Rich Nute
Hi Ken: See my paper on floating circuits in the Product Safety Newsletter: http://www.ewh.ieee.org/soc/emcs/pstc/tech-spk.htm This should answer all your questions. If not, please get back to me, and I'll answer any additional questions you may have. Best regards, Rich ps:

Re: Risk assessment

2000-12-07 Thread Rich Nute
Hi Stig: I believe you are interested in severity of injury, not potential for injury, or risk of injury. Here is a numerical assignment for severity of injury that I found in my files. I have no idea of its source. 10 Death 9 Long-term or permanent coma 8 Full body

Re: Polarity Markings on AC Adapters

2000-11-30 Thread Rich Nute
Hi George: Thanks for the quick response! Does this mean that the symbology is only a Japan requirement? and does it apply to ITE as well as audio-visual equipment? The referenced standard, EIAJ CP1104, is similar to IEC 417. Indeed, EIAJ CP1104 contains many

Re: Polarity Markings on AC Adapters

2000-11-30 Thread Rich Nute
Hi George: The dc polarity symbol is specified in: Symbol 01060 (taken from JEIDA 11) EIAJ CP-1104 (1998) Terms and Grpahical Symbols for Audio and Audio-Visual Equipment Technical Standardization Committee on Audio-Visual Equipment and Systems Electronic Industries

Re: component spacing question

2000-11-30 Thread Rich Nute
Hi Ken: I wanted to pose the group a question in regards to spacing requirements for the U.S. Many UL standards allow for the exception of components (such as semi conductors, switches, etc) to not meet spacing requirements (as they usually have different standards they meet

Re: Got a beef with an NRTL ...

2000-10-19 Thread Rich Nute
Hi Doug: Your message was not clear whether you submitted your product to the same NRTL that certified the power supply. Basically, your cert engineer has put YOU in the middle of a beef between cert engineers or between cert houses. Your cert engineer found a fault in the power supply

For UL watchers... a job opening...

2000-10-19 Thread Rich Nute
... check out: http://www.ul.com/about/newsrel/nr101300.html Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org

Re: Laser Safety Calculations

2000-10-17 Thread Rich Nute
Hi George and Chris: Better still, TC76 should provide a spreadsheet such that, upon entering all the data, the spreadsheet does the calculations and gives you the emission level and the emission Class. Regards, Rich --- This message is from the

Re: Flame Testing of Plastics

2000-10-12 Thread Rich Nute
Hi Richard: When testing plastics, the flame is applied for a specified period of time, removed for specified period of time and the process is repeated for a specified number of cycles. Is the procedure attempting to correlate with observed fire patterns in equipment, or is it

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