Re: [PSES] AC Mains Outlet fuses or daul pole breaker??

Hi Brian: In 1998, I wrote a column, Technically Speaking, in the Product Safety Newsletter that addresses this topic. See attached. (Since the listserver does not accept attachments, subscribers should e-mail a request to me.) Best regards, Rich From: Kunde, Brian

Re: [PSES] Measurement Uncertainty Above 18 GHz

In the field of compliance, we are not looking so much for an accurate measurement (where measurement uncertainty would be important), but rather to determine if the equipment is under the limit. Most of the time, the equipment should be comfortably under the limit so that uncertainty of

Re: [PSES] Low current Transformer OC Protection

Hi Brian: It sounds to me as though you have an “impedance-protected” transformer. A common example in the USA is a doorbell transformer. The output can be shorted all day, and the transformer will not overheat (exceed the insulation temperature ratings). The transformer cannot

Re: [PSES] Using 60hz motors in 50hz countries

> Can AC brushless motors (in this case 230V~ 3-phase > 3hp motors) that are rated "60HZ" be used in products > going to countries that have 50HZ power? Ask the motor manufacturer. In addition to running slower, the motor probably does not have enough iron to produce enough power, and will

Re: [PSES] ELECTRIC SHOCK historical papers

52-1201 <mailto:p.perk...@ieee.org> p.perk...@ieee.org From: Richard Nute [mailto:ri...@ieee.org] Sent: Wednesday, September 21, 2016 6:57 PM To: 'Pete Perkins' <peperkin...@cs.com <mailto:peperkin...@cs.com> >; EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.I

Re: [PSES] ELECTRIC SHOCK AS IT PERTAINS TO THE ELECTRIC FENCE

Hi Pete: Are the non-copyrighted papers (such as the UL “Bulletins of Research”) in the TC64/WG4 library available for public distribution? Rich From: Pete Perkins [mailto:0061f3f32d0c-dmarc-requ...@ieee.org] Sent: Wednesday, September 21, 2016 2:29 PM To:

Re: [PSES] ELECTRIC SHOCK AS IT PERTAINS TO THE ELECTRIC FENCE

Hi Doug: Thanks! Any other Bulletins of Research sources? Any topic. Rich From: Douglas Nix [mailto:d...@mac.com] Sent: Wednesday, September 21, 2016 12:32 PM To: Rich Nute Cc: IEEE EMC PSTC Subject: Re: [PSES] ELECTRIC SHOCK AS

Re: [PSES] standard for power suply for server room.

I would seriously consider pointing out to your customer that their specified supply voltage is not a common one I suspect your customer already knows this. The issue is determining that the product is safe, given that the mains ratings exceed those in many safety standards. While

[PSES] ELECTRIC SHOCK AS IT PERTAINS TO THE ELECTRIC FENCE

Underwriters Laboratories did basic research in the field of safety and published the results of that research in a series of "Bulletins of Research." At least 58 bulletins were published relating to fire, explosion, and electric shock. One of those Bulletins, "Electric Shock as it Pertains to

Re: [PSES] Measurement Accuracy

I was wondering if anyone was aware of any guidance documents that provided acceptable levels of uncertainty when conducting various tests. I didn’t know what “uncertainty” is, so I did a Google search and found this reference:

Re: [PSES] Fire ants

Hi Scott: Thank you for the reference. The one from Texas Tech was quite enlightening. Rich - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the

Re: [PSES] IEEE Elections and Constitution

I have already voted “no” for the amendment. The proposed amendment and rebuttals are: http://www.ieee.org/about/corporate/election/amend ment.pdf The rebuttals are worth reading. They convinced me to vote “no.” Best regards, Richard Nute Life Fellow, PSES IEEE Bend, Oregon

Re: [PSES] Fuses can affect performance other than safety!

> 'Live versus recorded' demos (with good results) date way > back to the early > 1950s, first in USA and soon after in Britain. Yes. In the '50's, I attended such a demo by Ampex and the San Francisco Symphony at the SF War Memorial Opera House. I was on the main floor about 2/3 back from the

Re: [PSES] Fuses can affect performance other than safety!

If you put a carefully-chosen fuse in series with a loudspeaker, you can measure intermodulation distortion in the voice-coil current due to the element changing its resistance with temperature. What would be the parameters of a fuse that would minimize the element changing its

Re: [PSES] Fuses can affect performance other than safety!

Link doesn't work for me. I'm devastated. (;-) Try: http://www.synergisticresearch.com/ and scroll down to “Synergistic Research Quantum Fuses.” Enjoy the other products such as power cords that make a difference in the sound you can hear! (The specs don’t indicate whether the

[PSES] Fuses can affect performance other than safety!

The “proper” fuse can make a difference in audio quality (sarcasm). See the audio review of replacing an ordinary fuse with a Black Quantum fuse (for only USD 119): http://www.synergisticresearch.com/sr-quantum-fuses-review/ Rich -

Re: [PSES] Taiwan and Korean approvals

Can someone recommend a lab that can do BSMI and Korean approvals please? UL has testing offices in both countries. I used them for BSMI. Rich - This message is from the IEEE Product Safety Engineering Society

Re: [PSES] SAFETTY FEATURES controlled by ....SOFTWARE

> my 'tactic' has been to > prove that the code is NOT a safety-critical component Amen! Rich - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your

Re: [PSES] SAFETTY FEATURES controlled by ....SOFTWARE

I have virtually no experience in software safety. I'm a hardware guy. I suggest simulating failures in the sensors (hardware) that gives the software info about what state the battery is in. And, simulating failures of the hardware controlling the charging, discharging, and

Re: [PSES] Safety requirements in US

At least Walmart has a policy regarding the safety of the products it sells: http://corporate.walmart.com/suppliers/minimum-requirements http://cdn.corporate.walmart.com/d1/7e/ee6f5c8942f69ad4183bc0683771/standards-for-suppliers-manual.pdf The manual covers a lot of stuff, and is simply stated.

Re: [PSES] Safety requirements in US

> I cannot see a reason not to have a federal installation > code for all 50 states. The hodgepodge of local rules > and regulations seems, on the surface, unnecessarily > complicated. NIH. Rich - This message is from the

Re: [PSES] Safety requirements in US

Hi Scott: Regarding local requirements in a state, county or city, how can they buy a product for particular state, county or city? Normally we sell the product to whole country and it sounds strange to me. What is the normal practice to restrict the movement of the imported

Re: [PSES] Safety requirements in US

What is the best practice for the suppliers/importers to demonstrate the compliance with relevant requirements? NRTL certified. Rich - This message is from the IEEE Product Safety Engineering Society emc-pstc

Re: [PSES] Safety requirements in US

Hi Scott: For consumer and household products, compliance with CPSC requirements is required. No. Only products considered “substantial product hazards” such as hair dryers need comply with CPSC requirements. However, any consumer product that injures someone is subject to CPSC

Re: [PSES] Safety requirements in US

Within EU, most of electrical products are covered by LVD and GPSD. In US, which body, law and standards are responsible for the similar regulatory? In the USA, we have a number of entities that oversee electrical safety: AHJ, enforcing the local (state, county, or city) electrical

Re: [PSES] NEC 2017

When I worked at an NRTL, a story circulated (veracity never verified, but useful for hawking testing services) about a person in Oregon who purchased a non-approved exercise stroller appliance from overseas via the Internet. It subsequently caught fire and burned the house down. The

Re: [PSES] Friday Question

ISO 8373 defines robot as "An automatically controlled, reprogrammable, multipurpose manipulator programmable in three or more axes, which may be either fixed in place or mobile for use in industrial automation applications." My Roomba doesn’t fit this definition. First, it is only

Re: [PSES] NEC 2017

The NEC is a model standard and intended to be adopted by local and state AHJs. In doing so, the AHJs often take exception to some requirements, and add some requirements. In adopting the NEC, the AHJs must specify what “listing” means – what third-party certifiers are acceptable to the

Re: [PSES] Applicable standards for hoverboard in EU

> So are you working on a proposal to ACOS (via ANSI > and SMB, of course) to start the process? Step by step. Small steps. One step is to convince this august group. And you. Can't propose to SMB or ACOS without support from their members and member countries. Not (yet) many are willing

Re: [PSES] Applicable standards for hoverboard in EU

> One standard for each energy source is a good idea, but > there are six or more sources, so it would not be swiftly > done. Here are the energy sources that are commonly addressed in product safety standards: 1) Electric shock (electrically-caused injury). 2) Electrically-caused

Re: [PSES] Applicable standards for hoverboard in EU

> how long would it take to turn the 111 standards in > 60335 into one? I envision a standard for each energy source, for example electric shock. Electric shock from a toaster, or cooker, or microwave, is the same as electric shock from a TV, or computer, or voltmeter. This is largely

Re: [PSES] Oscilloscope probe calibration

] Sent: Monday, July 11, 2016 7:15 PM To: EMC-PSTC@LISTSERV.IEEE.ORG; Richard Nute <ri...@ieee.org> Subject: Re: [PSES] Oscilloscope probe calibration Hi Rich, Although useful, the literature from measurement companies and be misleading and rarely descirbe the situation completely. M

Re: [PSES] Oscilloscope probe calibration

We're seeing an issue with scope probes, and I'd appreciate suggestions, or just information on how others handle calibration. Start by studying this pamphlet: http://circuitslab.case.edu/manuals/Probe_Fundamen tals-_Tektronix.pdf http://www.ni.com/white-paper/14825/en/#toc1 If you

Re: [PSES] software safety

> You have touched on an interesting topic, and one that > IEC 62109-1,2 tries to address. Namely, redundant > hardware performing a safety function. The hardware > evaluated for single fault tolerance and the software > automatic controls used in a safety function evaluated > against Annex H of

Re: [PSES] Fire requirements in standards

> Why would they need to limit scope to just business > machines and the like? Why couldn't this be applicable > to a broad range of electrical equipment, from television > receivers to solar inverters? Traditionally, product safety standards have been written for a specific product. Few

[PSES] Product Safety Newsletter, Volume 7, Number 4, July-August, 1994?

the hard-copy to me; I will scan and return the original to you. Thanks, Richard Nute ri...@ieee.org <mailto:ri...@ieee.org> - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. T

Re: [PSES] Strain Relief Test (SEMI S2)

Anchor the box, and do the 35 lb. test. If it passes, you’re done. If it fails, you have the ammo to change to an appliance coupler. It’s a simple and easy test. The pull test proves that the anchor hole and cord diameter are the right dimensions. We already know that the anchor

[PSES] software safety

Software safety... what is it? At the very least, it is software control of a safeguard. In printers, software shuts down the moving parts when the cover is opened. In CD drives, software shuts down the spinning disc and turns off the laser. No, these shut-downs are not done with a physical

Re: [PSES] [BULK] Re: [PSES] Fire requirements in standards

I agree that 62368 attempts to allow for more flexibility the process of designing a safe product, but in the specific case of fire enclosures there is in fact a considerable impact where some existing product can not be certified to the new standard without significant product redesign.

Re: [PSES] Fire requirements in standards

Hi (the other) Brian: > This subject is very interesting to me. If I wanted to > know more, is getting a copy of 62368-1 worth reading > or will I have to wait for the proposed changes to > 60950-1 to come out, or what do you recommend? Sooner or later, you will need 62368-1. And, you should

Re: [PSES] SV: [PSES] insulated wires

> Wires which can't document UL or any other approval, > will mean a potential > fail verdict when a CBTL is doing the report. Maybe. Wire insulation which does not need to be basic insulation need not be UL-certified. However, most CBTLs will not recognize this aspect; they will insist that all

Re: [PSES] earthing through PCB traces

> I also know this. However some labs are not in favor to > this statement.They interpret it in different way like this > is only applicable to internal components of sub- > assembly that is IEC 60950-1 or IEC 60065 certified. In > addition, it is only allowed during transition period. As far as

Re: [PSES] earthing through PCB traces

Hi Boštjan: > What is your view to this statement? How should we fill > the verdict in the test report in this case with pass or > N/A? I would say the verdict is "pass." The basis is the paragraph I quoted. No matter the standard, the PE circuit must be capable of carrying the fault

Re: [PSES] earthing through PCB traces

Hi Boštjan: Consider this IEC 62368-1, 4.1.1, paragraph: "Components and subassemblies that comply with IEC 60950-1 or IEC 60065 are acceptable as part of equipment covered by this standard without further evaluation other than to give consideration to the appropriate use of the component or

Re: [PSES] insulated wires

Hi John: Also, it might be worth reminding folks that single-pole fusing is OK for defined-polarity mains supply systems (e.g. the UK, and some N.American systems) if it is in the Line/Live/”Hot” conductor, but not in undefined-polarity systems as found on the European Continent and

Re: [PSES] insulated wires

AFAIK, that requirement does not apply if a correctly fused appliance inlet is used because that should allow smaller gauge wiring from its outlet terminals – and that is quite common (or at least it was) for 60950 equipment. Wire rating (in 60950 equipment) is based on normal-condition

Re: [PSES] insulated wires

Insulated wires, like any other component, must be used within their ratings. Voltage, temperature, ampacity, etc. And, if the equipment is to be certified, the wire must be certified. These days, most wire is surface printed with its ratings and certifications. A typical PVC wire that is

Re: [PSES] AMA Warns of Harm from LED Streetlights’ Blue Light

Thanks for the URL to the AMA website. Unfortunately, the AMA doesn't give any color temperature or intensity numbers for "harmful human and environmental effects of high intensity street lighting." So, how are we to know what is acceptable to the AMA? As safety engineers, we cannot design a

Re: [PSES] Power Supply Safety approval

> If it's not multimedia, why was 60065 applied? Mr. McBurney "submitted a product for CB certification to IEC/EN/UL 60065." Rich - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To

Re: [PSES] Power Supply Safety approval

> There are differences, but I suppose citing Guide 112 > would deal with that. I don't believe that Guide 112 applies as this equipment was not designated "multimedia" equipment. If it was multimedia, Clause 3 of 60065 would apply, which references 4.2 and 4.3 of 60065 which is the meat of the

Re: [PSES] Power Supply Safety approval

I submitted the CB documentation for the power supply along with the product to the safety testing agency. I am surprised that the testing agency decided to dismantle the power supply and thoroughly evaluate it even though it is already pre-approved. While the power supply meets 60950

Re: [PSES] fire safety test methods for different country standards

> This is my recollection of where 240VA came from and > how it was used. In a 1966 UL meeting with industry on the requirements in UL 478, the minutes report: "Where high current is available at potentials down to about 2 volts, enough energy is available to melt and splatter metal from neck

Re: [PSES] fire safety test methods for different country standards

> The 240VA "Energy Hazard" was not a > consideration for the protection against Fire but a limit > value for accessible parts by the User. The energy hazard requirement (in the 950-series standards) is that the conductors shall not be bridged by the test finger (which has a spherical tip). If

Re: [PSES] fire safety test methods for different country standards

> The 15W is the *dissipated* power level to determine if > PIS. The standard is somewhat ambiguous because it uses > the term 'location' in definition, but 'circuit' in 6.2. Well... the intent was the maximum power available into a fault. Rich -

Re: [PSES] fire safety test methods for different country standards

> Example: I measure and determine that an electrolytic > capacitor temperature is compliant with the standard, but > what happens when that capacitor eventually fails due to > large ripple current and then overheats and catches fire. > That's a single fault condition (a component fault), but

Re: [PSES] fire safety test methods for different country standards

> So, for the protection against FIRE, we have two energy > rates, 100VA and 240VA, used across quite a number of > standards, and the units are wrong. Should be Watts. Agree. But, for pessimism, use VA. My experience and tests show that a product fire can be started by 15 watts! The

Re: [PSES] fire safety test methods for different country standards

> " Safety standards are not tested to see if they accomplish > the objective" > > I'm not sure how one would go about doing that, other > than gathering data from customer returns and from > product recalls. All safety standards include means to determine if the product complies with the

Re: [PSES] fire safety test methods for different country standards

240 VA (not W) is defined as "energy hazard" in UL/IEC 60950 and its predecessors, UL 950 and UL 478. "Energy hazard" only applies if the potential is 2 V or more. (The dimension for energy is the Joule, not the volt-ampere.) The standards state: "A risk of injury due to an energy

Re: [PSES] fire safety test methods for different country standards

> Not following instructions is foreseeable misuse... Depends. I define "misuse" as using the product for some use other than its intended use. Standing on a chair is misuse of the chair. Misuse (my definition) cannot be foreseeable because it depends on what the user needs to do (and has

Re: [PSES] fire safety test methods for different country standards

Hi John: Thanks for your additional comments. > Could it be that the scenarios which the standards > committees envisage are not "the real deal" In my opinion, this is the case. > OR that the > products which cause the fires just don't comply with the > standards? Of course, counterfeit and

Re: [PSES] fire safety test methods for different country standards

Our most common and serious safety issue is that of product electrically-caused fire. I subscribe to "In Compliance" weekly recall notices; most are fire. As Gert Gremmen has stated, no fault-testing has resulted in a product fire in the test lab, yet product fires continue to occur in the

Re: [PSES] fire safety test methods for different country standards

Hmm. Thanks to Ted Eckert, the small tablet may have been methenamine. Rich - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your

Re: [PSES] fire safety test methods for different country standards

Thanks, Brian. I recall now. I used hexamine tablets. I used two sizes, one about ½ inch diameter and ¼ inch thick, and the other about the size of an aspirin tablet. I placed the hexamine on top of the component I expected to catch fire, ignite the pellet, put the enclosure back on,

Re: [PSES] fire safety test methods for different country standards

Hi John: Thanks for your comments. In the end, the “solution” was a different sort of pragmatic approach because the boards were always enclosed in hermetically sealed high pressure (10,000 psi+) / temperature (180C+) -resistant stainless steel tubes which have very little

Re: [PSES] fire safety test methods for different country standards

Hi Scott: “In general, the users and testing houses are referring to the rating of UL yellow card rather than the actual test on individual final designed pcb. Should we use it to object their normal practice. How often is it successful?” Testing in place is a

Re: [PSES] fire safety test methods for different country standards

In my last job I tried to do something similar w.r.t. PWB materials for applications where V-1 or better materials aren’t any good because the retardants result in reduced service lives in hostile equipment environments, whereas some specific (and very special!) HB materials last much

Re: [PSES] “Design It In!”

I agree with the differences between Europe and the USA. However, in my experience, product safety and product liability are treated separately. Liability (in the USA) occurs after someone claims that he has been injured by the product. Lawyers run this. The lawyers may or may not

[PSES] “Design It In!”

I would agree that “Design It In!” is a good and appropriate slogan. Unfortunately, there is no formal training program for product safety professionals; learning about how to do third-party certification submittals is on-the-job learning. Same for the professionals at the

Re: [PSES] Meet some of the list admins at the PSES Symposium next week

I'm sure we all agree that NO failures is the goal, but to John's point, I think it would be instructive for some to know what types of failures are generally found. (e.g. marking, ventilation openings, temperature limits, dielectric strength, ground bonding, critical components, clause

Re: [PSES] Meet some of the list admins at the PSES Symposium next week

A failure at a certification house potentially causes delay of the product regardless of the type or magnitude of the failure. The goal is NO failures. Rich From: John Woodgate [mailto:jmw1...@btinternet.com] Sent: Tuesday, May 10, 2016 12:59 PM To:

Re: [PSES] SV: [PSES] Residual-Current Device

60950 (and 62368) rely on physical and behavioral safeguards for safety. They have no provision for relying on code (firmware or software) safeguards for safety. These standards require the equipment to be safe in the event of a single fault. As I understand the original comment, the

Re: [PSES] SV: [PSES] IEC60950-1, Table 2N - creepage

rds Amund Fra: Richard Nute [mailto:ri...@ieee.org] Sendt: 18. april 2016 20:59 Til: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> Emne: Re: [PSES] IEC60950-1, Table 2N - creepage Hi Amund: 2.10.6 addresses printed wiring boards. 2.10.6.3 addr

Re: [PSES] IEC60950-1, Table 2N - creepage

Hi Amund: 2.10.6 addresses printed wiring boards. 2.10.6.3 addresses insulation between conductors on the same inner surface of a printed board which invokes 2.10.5.5, which is cemented joints. Table 2N (Amendment 1) applies to the creepage distance of the cemented joint. If

[PSES] A quote from Tim Kelly, University of York

John Allen (UK) gave the name of Tim Kelly. Looking at some of his work on the web, I found this: Safety compliance is a very demanding activity, as the standards can consist of hundreds of pages and practitioners typically have to show the fulfilment of thousands of safety-related criteria.

Re: [PSES] SV: [PSES] EU's new approach directive transitions

". Risk Assessment is a qualitative (estimate based on experience) venture." I don't have experience in RA, so I guess I can't do it. I guess I have to hire someone who has RA experience. This is very much like the certification house manager who told me that product safety is an

Re: [PSES] SV: [PSES] EU's new approach directive transitions

Based on your question, your best bet would be to read ISO 12100 Having sat on numerous standards committees, many of the requirements come from BOGSAT (Bunch Of Guys Sitting Around Talking), not from science. I am interested in the academic (or scientific) background for RA rather

Re: [PSES] SV: [PSES] EU's new approach directive transitions

". hopefully involving some who have had "field" experience of similar products and the HAZARDS that they have faced." ". become familiar/"comfortable" with what it is trying to achieve and how it is prompting/helping YOU to do it." Can you provide a bibliography of articles by

Re: [PSES] "For indoor use only" on External Power Supply

> Depending on the > product I could easily see using an indoor only rated > power supply outdoors as possible misuse. That depends on your definition of "misuse." If "misuse" means using the product for something other than its intended use, then using the product outdoors is not misuse. If

Re: [PSES] "For indoor use only" on External Power Supply

OTOH, apart from instructions and symbols, how else can manufacturers begin to address the issue of “risk reduction” other than making the products “absolutely safe”? Most products are absolutely safe for all practical purposes. As you read this, you are safe. And, you are acting

Re: [PSES] "For indoor use only" on External Power Supply

There is a gap between standalone transformer standard requiring warning "For indoors use only" and combined product requiring no warning. There is no uniformity (standardization?) among safety standards for the use of the “indoor use” symbol. Virtually all electrical products are

Re: [PSES] "For indoor use only" on External Power Supply

If without the warning and symbol, are the users qualified to use the products outdoor? Users are rarely qualified to use products outdoors (regardless of the warning and the symbol). But products can be qualified for use outdoors. Standards have additional requirements for

Re: [PSES] Commom mode current vs. differential mode current and LISN

Hi Richard: The usual class Y value of 4,700pF presents an impedance of only 1.13 ohms at 30MHz, so it provides a very substantial unbalance to create CM from a neighbour's DM All of the products I have seen have two Y capacitors, one from L to E, and one from N to E. With these

Re: [PSES] Commom mode current vs. differential mode current and LISN

- A device with a single class X capacitor from neutral to ground. Safety standards require the capacitor to be Class Y. Rich - This message is from the IEEE Product Safety Engineering Society emc-pstc

Re: [PSES] EU's new approach directive transitions

Scott Xe said, “The risk assessment is unclear how to do it and any reference to follow.” I agree. Risk assessment is an abstraction. ISO/IEC Guide 51, the basis for risk assessment, defines risk as the “combination of the probability of occurrence of harm and the severity of that

Re: [PSES] UL Certification status of a re-sold UPS

Hi Lauren: Whether used (resold) or rebuilt, the equipment must meet all the requirements of the standard for the certification mark to be valid. If the equipment has been rebuilt and re-certified, you know that it meets all of the requirements. If the equipment is used, you don't

Re: [PSES] Insulation testing

Hi Ralph: Some say 0th fault to mean it is expected to fail, therefore you fault it, before applying a single-fault. Never heard of this process. And never used this process. And have never seen it in a safety standard. If bonding impedance test passes, then the circuit is

Re: [PSES] Insulation testing

Hi Ralph: It seems that the standards are treating functional ground connections (those that do not pass a bonding impedance test) as a 0th fault, not a single fault. For the bonding impedance test (fault current), what would be the test current? Would it be twice the rating of

Re: [PSES] Ambient temperature

I've used a 5-sided cube inside the chamber to create a draft-free environment for performing flammability tests. The open side faces the front so you can see the equipment. The test flame is quite still. I would believe this would also work for temperature measurements. Rich >

Re: [PSES] Reliable means to attach thermocouple to object

> > You are dating yourself. How many people on this list > know what a TO-220 is. > > Some of us also know what a CK-722 is, a 5Y3 and an 80. > Among other things. Ahh, yes. And Sams Photofact. And Hugo Gernsbach's "Radio-Electronics" magazine. -

Re: [PSES] IEC 61010-1 and VDRs in OVC III environments

> FWIW, have recorded >4kV transients at a North Carolina > site twice during previous 14 months. Unfortunately, we don't know whether the cause was by operation of equipment, operation of a transient suppression device, or atmospheric discharge. Since the occurrence rate is so low, and the

Re: [PSES] IEC 61010-1 and VDRs in OVC III environments

Hi Peter: Don't use the VDR or any transient suppression. Take it out. Your insulation is good enough and is not likely to be damaged by a transient over-voltage. VDRs and most other transient suppression schemes may protect the immediate equipment, but generate transients for other

Re: [PSES] Insulation testing

Hi John: How do you demonstrate the dielectric strength between mains and user accessible circuits when the accessible circuits are referenced to chassis? Disconnect the ground, and connect the low end of the hi-pot tester to the user-accessible part (circuit). Don't touch the

Re: [PSES] Reliable means to attach thermocouple to object

> " ...operating at a temperature of 120 degC..." has no > meaning. Test conditions and component ID? A Tj of > 150deg does not mean that you are allowed 150deg on the > component body. TI, ST, and others have published some > good stuff on calculating component temps for power > semiconductors.

Re: [PSES] Ancillary Equipment per EN 301 489-1

Hi David: The above is due to disagreement with customer. Apparently, the customer wants testing and certification, so give it to him! (The customer is always right!) Best regards, Rich - This

Re: [PSES] Energy in certain items

> Does anyone know the energy [joules] in a standard stick of > dynamite, or a gallon of gasoline? Not the answer, but may be useful: 4,184,000,000 J = 1 ton of TNT For a comparison of energy in dynamite and gasoline, and for "The nonsense about gasoline and dynamite," see:

Re: [PSES] NRTL invoices

Check your contract! > -Original Message- > > Starting last year, noticed that some NRTLs are charging > twice for same audit. For example - same equipment > category, same file reference, but getting charged > factory FUS audit fees for both audit of products in > production and

Re: [PSES] NRTL invoices

> - U.S. customer site - auditor arrives 0930, inspects > units that do not bear his agency's marks (and have > never been assessed by any NRTL), writes variation > notice, then leaves about 1100. Why was the inspector allowed to inspect units that do not bear his certification house's mark? Do

Re: [PSES] NRTL invoices

> - Asia site - auditor writes variation notice because hi- > pot test level is too high. Their agency required 2500V, > another wanted 3kV. > - Asia site - auditor writes variation notice because > product is being hi-potted twice during production > process, and because one test level is a bit

Re: [PSES] NRTL invoices

> Refusal to pay for any audit services rendered that the > NRTL deems necessary will result in suspension of right > to apply their mark to any products. Pay for services rendered. If no service is rendered, then don't sign that there was service (and indicate at that time that there was no

Re: [PSES] NRTL invoices

ployer's products. The compliance engineering > community should push back. No longer view many > compliance agencies as being part of a sustainable and > rational economic model. > > Brian > > -Original Message- > From: Richard Nute [mailto:ri...@ieee.org] > Se

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