Earth Leakage Measurement Circuit per EN 60950
Duncan and PSNet To build the network described in 950 is not trivial if one wishes to meet all the requirements to achieve adequate performance over the specified frequency range, in the expected environment in which it must operate. Because this is not a trivial matter, IEC 60990 'Measurement of Touch Current and Protective Conductor Current' has an entire section devoted to measuring instruments and another covering calibration to show adequacy. If you wish to build such an instrument, I recommend that you get this standard. You can order it directly from the IEC website in Geneva. There is one commercial instrument which meets the requirements described in 950, the Simpson model 228 Leakage Current meter. Look at their website. Incidentally, I use this instrument in my own work. There may be others available. If you really want to continue to build your own instrument, but need some additional help, I can recommend an experienced measurement equipment consultant who would probably help you. Contact me privately for this. Good luck in your preparation for this project. :>) br, Pete Perkins Convenor, IEC TC74/WG5/IEC 60990 - - - - - Peter E Perkins Principal Product Safety Consultant Tigard, ORe 97281-3427 +1/503/452-1201 phone/fax p.perk...@ieee.org email visit our website: http://ourworld.compuserve.com/homepages/peperkins - - - - - - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Copy of: D of C - Who Signs?
Marin: Barring non compliant products from entry soon makes its point rather than trying to untangle the legal liability in such rare cases. Ralph Cameron Independant Consulting and EMC suppression in consumer electronics (after sale) - Original Message - From: Martin Green To: 'Allan G. Carr' Cc: 'Price, Ed' ; Sent: Thursday, November 25, 1999 6:05 AM Subject: RE: Copy of: D of C - Who Signs? > > Alan, > > As far as the quotation is concerned, I would refer you to the words in Reg. > 40(2)(c), Erg 57(2)(c), Erg 70(2)(c) for clauses detailing who signs the > DoC. Under the UK regulations it will, as I said in my email, "be signed by > or on behalf of the manufacturer or his authorised representative and > identify that signatory" > > As far as going to court is concerned, I too thought that action would be > taken against the responsible person, but when I discussed this with both > the DTI and some lawyers they said that as the offence would be "placing on > the market a product that did not meet the protection requirements" - or > similar words, and it would be a charge raised in a UK court, then it is the > person selling it that is charged. Apparently, there is no cross border > joint jurisdiction in the EU for CE marking offences. I understand that the > UK authorities would inform the EU commission and they in turn would inform > the authorities in Belgium. The Belgium authorities may then choose to > investigate the offence to see if an offence had been committed in Belgium, > under Belgium law. However, there is no doubt that the UK courts could not > take action against a citizen in Belgium for this type of offence. > > Whether the Belgium authorities would be able to charge a Belgium citizen > with an offence committed in the UK is open the question. It is like being > charged for speeding in Germany and having a UK court hear the case. It does > not work. As many will know to their cost (including me!), if you commit a > motoring offence in Germany then you can pay a fine either on the spot or in > court. Usually it on the spot - even if you are British! The UK courts do > not hear motoring offences committed in Germany. > > Regards > > Martin > > -Original Message- > > From: Allan G. Carr [SMTP:e...@acarr.demon.co.uk] > > Sent: 25 November 1999 13:43 > > To: Martin Green > > Cc: 'Price, Ed'; 'emc-p...@ieee.org' > > Subject: Re: Copy of: D of C - Who Signs? > > > > Martin > > > > Thanks for the comprehensive reply to my post. > > > > I have the following comments:- > > > > >The UK EMC regulations do not say > > >the DoC is signed by the responsible person. They say the DoC must be > > >"signed by or on behalf of the manufacturer or his authorised > > representative > > >and identify that signatory". > > > > Sorry to be pedantic but the UK Statutory Instrument 1992 No.2372 does > > not contain the above quote. This quote is from EC EMC Guidelines > > which therefore clarify the issue. > > > > > > >The question always arises as to who ends up in court. As an example, if > > >the DoC is signed in the USA, for a product made in Mexico, being sold by > > >distributors in 10 of the member states in the EU, with the authorised > > rep > > >in Belgium acting as the responsible person and there is a court case for > > >infringement of the UK EMC regulations, who ends up in court? The action > > is > > >taken in UK by the Trading Standards Officers against the person placing > > the > > >product on the market in the UK. The answer is the distributor. The UK > > has > > >no jurisdiction over the authorised rep in Belgium or the manufacturer > > >outside the EU. > > > > UK Trading Standards tell me that in the above example the prosecution > > would be handed over to the EC country of residence of "the responsible > > person" who keeps the documentation - in this case Belgium. > > > > However the UK distributor could be in the firing line if UK Trading > > Standards were not happy with the result. > > > > > > > > Thanks again for your excellent response > > Allan > > > > > > In message , Martin Green > > writes > > >It is always interesting to read the "legal" interpretation of these > > >documents. I now understand why lawyers make so much money. > > > > > >If you have the staying power you might find this or interest/value, > > >otherwise hit the delete button! > > > > > >The interpretation below is incorrect. The UK EMC regulations do not say > > >the DoC is signed by the responsible person. They say the DoC must be > > >"signed by or on behalf of the manufacturer or his authorised > > representative > > >and identify that signatory". > > > > > >They also say the that DoC must give the name and address of the > > responsible > > >person and where that person is not the manufacturer, of the > > manufacturer. > > > > > >For those who read this stuff and are not used to the arcane legal words > > >inside UK Statutory Ins
Re: Humidity Test
Bill, Check out ASTM A380 and ASTM A967, 100% humity at 38 C. http://www.astm.org . Richard Haynes 609-497-4584 -Original Message- From: Matthew Meehan To: Jacowleff, Bill Cc: emc-p...@ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, November 11, 1999 4:00 AM Subject: Re: Humidity Test > >> Can anyone steer me to an appropriate standard that would specify >> Humidity tests for a heavy industrial product? >> >> Best Regards, >> >> Bill Jacowleff > >Bill, >"Appropriate" covers a lot of ground. Especially since you didn't specify >your market (country, equipment category (e.g. semiconductor machinery)). >You also didn't mention if you are interested in compliance - or if you're >just looking for a little light reading. >If you're looking for international standards try searching: > >http://www.iec.ch/ > >Since you have not specified I'll just stick with the general standards >(there may be a more suitable product family standard). > >IEC 60204-1 (1997-10) >Electrical equipment of industrial machines - Part 1: General requirements >Provides a requirement stating that machines must be capable of correct >operation at 40 degress C (humidity <=50%). >This requirement can be altered however by agreement with your customer (see >Appendix B). > >You might also consider the following standards: > >IEC 60068-2-56 - Ed. 1.0 - Bilingual >Title: Environmental testing - Part 2: Tests. Test Cb: Damp heat, steady >state, primarily for equipment >Publication date: 1988-12 >TC: 104 (ENVIRONMENTAL CONDITIONS, CLASSIFICATION AND METHODS OF TEST) >Pages: 15 >Price: 36.00 CHF (price code : H). >Abstract: Determines the suitability of electrotechnical products, >principally equipment, for use and storage under conditions of high >humidity. >You would also need the IEC 60068-1 as well. I imagine a few different >tests plans are described in the standard. > >IEC GUIDE 106 (1996-07) Ed. 2.0 CHF 27.00 17 pages >Guide for specifying environmental conditions for equipment performance >rating >This standard is listed in the bibliography of the IEC 60204 > >Hope this helps. >Regards, >Matt > > > >- >This message is coming from the emc-pstc discussion list. >To cancel your subscription, send mail to majord...@ieee.org >with the single line: "unsubscribe emc-pstc" (without the >quotes). For help, send mail to ed.pr...@cubic.com, >jim_bac...@monarch.com, ri...@sdd.hp.com, or >roger.volgst...@compaq.com (the list administrators). > > > - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
EMC simulation software
NOTE: This mail is for the subscribers of EMC-PSTC mailing list that aren't TREG subscribers. I have already mailed this mail to TREG group, and I want to thank Rusty, Jan, and Bechard above all, for their reply. Hello to EMC-PSTC group! I have the following info request: Who can suggest me a reliable EMC simulation tool for the design of PCB for mobile telecom equipments, predicting emissions and, possibly, immunity problems? In your opinion, is this software really useful for identify and correct EMC problems before doing lab tests according standards? Thank you for your attention Giovanni Tribellini - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Article to UL
I woudn't take the Washington Post articel seriously but unfortunately in the struggle for the media to retain readership they act as interpreters of things they don't fully understand and in the course of publishing spread technical inaccuracies. The article is only an opinion, albeit one sided. I would agree with Peter that not juch is to be gained by negative bashing. Manufacturers should voluntarily ascribe to saftey as an ethical and moral obligation and promote the profession of responsible engineering. The same should apply to EMC immunity in products. I'd like to see the Washington Post write about that. I could help them. Keep up the objective comments, they lead to progress. Ralph Cameron Independant EMC Consulting for suppression of consumer products lacking EMC. (After sale). - Original Message - From: To: Sent: Wednesday, November 24, 1999 8:08 PM Subject: Article to UL > > Hello group, > > It seems to me that the article in Washington Post, was written by someone > who really had not done their homework. It sounded as the article was > criticizing UL for not doing proper testing or not being able to write their > standards adequately. Like most of the people in the group, I am certainly > not a fan of UL for various reasons that are outside the scope of this > particular subject, but one has to remember that almost majority of the > standards are written with manufacturers directly involved during the > generation of the standard. Obviously those of us who are being represented > in various standard committee we who are responsible for writing the > standard, try to influence the standard as much as we can in our industry > favor and test houses such as UL, CSA , BSI, more or less go along with it. > As for testing is concerned, all UL engineers as well as their counterparts > in other test houses only test the product to the clauses of the standard and > they are not allowed to go any further. On top of that, the way that any of > these standard are written it is widely open to interpretation so we as test > engineers always try to argue with the test house engineer to try to avoid > any failure. Another point to bear in mind is that the test house engineers > are only human like the rest of us and can make mistake or even overlook at > some points. Last but not least, most of us have seen a certified product > been slightly modified/altered by someone in our company for an unknown > reason and still bears the safety mark without even informing any of the test > houses concerned . So I believe we should look at the root casue of the > problem and try to improve the situation by > (a) be honest with the test houses during testing. > (b) by trying to encourage our designers to make the product almost fool > proof. > © do addition in-house testing that exceeds the requirements of the standard > (d) by being a truly responsible manufacturer. > > Thanks > Peter > > - > This message is coming from the emc-pstc discussion list. > To cancel your subscription, send mail to majord...@ieee.org > with the single line: "unsubscribe emc-pstc" (without the > quotes). For help, send mail to ed.pr...@cubic.com, > jim_bac...@monarch.com, ri...@sdd.hp.com, or > roger.volgst...@compaq.com (the list administrators). > > > - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Copy of: D of C - Who Signs?
Alan, As far as the quotation is concerned, I would refer you to the words in Reg. 40(2)(c), Erg 57(2)(c), Erg 70(2)(c) for clauses detailing who signs the DoC. Under the UK regulations it will, as I said in my email, "be signed by or on behalf of the manufacturer or his authorised representative and identify that signatory" As far as going to court is concerned, I too thought that action would be taken against the responsible person, but when I discussed this with both the DTI and some lawyers they said that as the offence would be "placing on the market a product that did not meet the protection requirements" - or similar words, and it would be a charge raised in a UK court, then it is the person selling it that is charged. Apparently, there is no cross border joint jurisdiction in the EU for CE marking offences. I understand that the UK authorities would inform the EU commission and they in turn would inform the authorities in Belgium. The Belgium authorities may then choose to investigate the offence to see if an offence had been committed in Belgium, under Belgium law. However, there is no doubt that the UK courts could not take action against a citizen in Belgium for this type of offence. Whether the Belgium authorities would be able to charge a Belgium citizen with an offence committed in the UK is open the question. It is like being charged for speeding in Germany and having a UK court hear the case. It does not work. As many will know to their cost (including me!), if you commit a motoring offence in Germany then you can pay a fine either on the spot or in court. Usually it on the spot - even if you are British! The UK courts do not hear motoring offences committed in Germany. Regards Martin > -Original Message- > From: Allan G. Carr [SMTP:e...@acarr.demon.co.uk] > Sent: 25 November 1999 13:43 > To: Martin Green > Cc: 'Price, Ed'; 'emc-p...@ieee.org' > Subject: Re: Copy of: D of C - Who Signs? > > Martin > > Thanks for the comprehensive reply to my post. > > I have the following comments:- > > >The UK EMC regulations do not say > >the DoC is signed by the responsible person. They say the DoC must be > >"signed by or on behalf of the manufacturer or his authorised > representative > >and identify that signatory". > > Sorry to be pedantic but the UK Statutory Instrument 1992 No.2372 does > not contain the above quote. This quote is from EC EMC Guidelines > which therefore clarify the issue. > > > >The question always arises as to who ends up in court. As an example, if > >the DoC is signed in the USA, for a product made in Mexico, being sold by > >distributors in 10 of the member states in the EU, with the authorised > rep > >in Belgium acting as the responsible person and there is a court case for > >infringement of the UK EMC regulations, who ends up in court? The action > is > >taken in UK by the Trading Standards Officers against the person placing > the > >product on the market in the UK. The answer is the distributor. The UK > has > >no jurisdiction over the authorised rep in Belgium or the manufacturer > >outside the EU. > > UK Trading Standards tell me that in the above example the prosecution > would be handed over to the EC country of residence of "the responsible > person" who keeps the documentation - in this case Belgium. > > However the UK distributor could be in the firing line if UK Trading > Standards were not happy with the result. > > > > Thanks again for your excellent response > Allan > > > In message , Martin Green > writes > >It is always interesting to read the "legal" interpretation of these > >documents. I now understand why lawyers make so much money. > > > >If you have the staying power you might find this or interest/value, > >otherwise hit the delete button! > > > >The interpretation below is incorrect. The UK EMC regulations do not say > >the DoC is signed by the responsible person. They say the DoC must be > >"signed by or on behalf of the manufacturer or his authorised > representative > >and identify that signatory". > > > >They also say the that DoC must give the name and address of the > responsible > >person and where that person is not the manufacturer, of the > manufacturer. > > > >For those who read this stuff and are not used to the arcane legal words > >inside UK Statutory Instruments this is often difficult to understand. > The > >problem is no one else in the EU gives guidance to the manufacturers who > are > >trying to CE mark their equipment correctly. The guidance documents from > >the EU commission are often confusing as well. So I have tried to > explain > >the "legal" interpretation as understood by some very senior lawyers in > UK > >with whom we have dealings. > > > >The way the EU tends to consider this is that the "responsible person" is > >the person (living body) who issues the DoC and holds the certification > >documentation, or evidence
Re: Copy of: D of C - Who Signs?
Martin Thanks for the comprehensive reply to my post. I have the following comments:- >The UK EMC regulations do not say >the DoC is signed by the responsible person. They say the DoC must be >"signed by or on behalf of the manufacturer or his authorised representative >and identify that signatory". Sorry to be pedantic but the UK Statutory Instrument 1992 No.2372 does not contain the above quote. This quote is from EC EMC Guidelines which therefore clarify the issue. >The question always arises as to who ends up in court. As an example, if >the DoC is signed in the USA, for a product made in Mexico, being sold by >distributors in 10 of the member states in the EU, with the authorised rep >in Belgium acting as the responsible person and there is a court case for >infringement of the UK EMC regulations, who ends up in court? The action is >taken in UK by the Trading Standards Officers against the person placing the >product on the market in the UK. The answer is the distributor. The UK has >no jurisdiction over the authorised rep in Belgium or the manufacturer >outside the EU. UK Trading Standards tell me that in the above example the prosecution would be handed over to the EC country of residence of "the responsible person" who keeps the documentation - in this case Belgium. However the UK distributor could be in the firing line if UK Trading Standards were not happy with the result. Thanks again for your excellent response Allan In message , Martin Green writes >It is always interesting to read the "legal" interpretation of these >documents. I now understand why lawyers make so much money. > >If you have the staying power you might find this or interest/value, >otherwise hit the delete button! > >The interpretation below is incorrect. The UK EMC regulations do not say >the DoC is signed by the responsible person. They say the DoC must be >"signed by or on behalf of the manufacturer or his authorised representative >and identify that signatory". > >They also say the that DoC must give the name and address of the responsible >person and where that person is not the manufacturer, of the manufacturer. > >For those who read this stuff and are not used to the arcane legal words >inside UK Statutory Instruments this is often difficult to understand. The >problem is no one else in the EU gives guidance to the manufacturers who are >trying to CE mark their equipment correctly. The guidance documents from >the EU commission are often confusing as well. So I have tried to explain >the "legal" interpretation as understood by some very senior lawyers in UK >with whom we have dealings. > >The way the EU tends to consider this is that the "responsible person" is >the person (living body) who issues the DoC and holds the certification >documentation, or evidence of conformity, in the EU (test reports/TCF/EC >Type examination certificate etc.) > >This is not necessarily the person who signs the DoC. The person signing >the DoC is the person who legally "binds" the manufacturer to the claims in >the DoC - as with a contract signatory. > >As the only authorities who may want to see the documentation are in the EU, >the responsible person must be in the EU as well. If the manufacturer is in >the EU he does not need an authorised rep (although he may appoint one) and >by default he would be the responsible person. > >Therefore you can think of it rather in the same way as signing a contract >for buying a house. The person who is legally purchasing the house signs >the contract. The contract can then be given to a third party such as a >lawyer for safe keeping and making available to anyone who legally needs to >see it. Of course if the house, new owner and lawyer all reside in the same >town, why give the contract to the lawyer to keep? > >So the basic rules are: > >1. If the manufacturer is located outside the EU, (including Switzerland) >then he must appoint an authorised representative to act on his behalf. > >2. The manufacturer or his authorised representative in the EU holds the >documentation and issues the DoC and is therefore the responsible person. >If the manufacturer does not appoint an authorised representative, or the >authorised representative is located outside the EU (why have one!) the >default is that the responsible person becomes the person who supplies >(places the product on the market) the apparatus. > >3. The person who signs the DoC can be anyone who is authorised by the >manufacturer to do so. Usually it is a manager or officer, but that person >is legally binding the manufacturer to the claims in the DoC, so it must be >some one authorised to do so. > >Naturally the EU messes things up a bit because the machinery directive >allows the responsible person to be outside the EU. But there are very >special provisions associated with that. The medical devices directive >requires the appointment of an authorised re
RE: Copy of: D of C - Who Signs?
It is always interesting to read the "legal" interpretation of these documents. I now understand why lawyers make so much money. If you have the staying power you might find this or interest/value, otherwise hit the delete button! The interpretation below is incorrect. The UK EMC regulations do not say the DoC is signed by the responsible person. They say the DoC must be "signed by or on behalf of the manufacturer or his authorised representative and identify that signatory". They also say the that DoC must give the name and address of the responsible person and where that person is not the manufacturer, of the manufacturer. For those who read this stuff and are not used to the arcane legal words inside UK Statutory Instruments this is often difficult to understand. The problem is no one else in the EU gives guidance to the manufacturers who are trying to CE mark their equipment correctly. The guidance documents from the EU commission are often confusing as well. So I have tried to explain the "legal" interpretation as understood by some very senior lawyers in UK with whom we have dealings. The way the EU tends to consider this is that the "responsible person" is the person (living body) who issues the DoC and holds the certification documentation, or evidence of conformity, in the EU (test reports/TCF/EC Type examination certificate etc.) This is not necessarily the person who signs the DoC. The person signing the DoC is the person who legally "binds" the manufacturer to the claims in the DoC - as with a contract signatory. As the only authorities who may want to see the documentation are in the EU, the responsible person must be in the EU as well. If the manufacturer is in the EU he does not need an authorised rep (although he may appoint one) and by default he would be the responsible person. Therefore you can think of it rather in the same way as signing a contract for buying a house. The person who is legally purchasing the house signs the contract. The contract can then be given to a third party such as a lawyer for safe keeping and making available to anyone who legally needs to see it. Of course if the house, new owner and lawyer all reside in the same town, why give the contract to the lawyer to keep? So the basic rules are: 1. If the manufacturer is located outside the EU, (including Switzerland) then he must appoint an authorised representative to act on his behalf. 2. The manufacturer or his authorised representative in the EU holds the documentation and issues the DoC and is therefore the responsible person. If the manufacturer does not appoint an authorised representative, or the authorised representative is located outside the EU (why have one!) the default is that the responsible person becomes the person who supplies (places the product on the market) the apparatus. 3. The person who signs the DoC can be anyone who is authorised by the manufacturer to do so. Usually it is a manager or officer, but that person is legally binding the manufacturer to the claims in the DoC, so it must be some one authorised to do so. Naturally the EU messes things up a bit because the machinery directive allows the responsible person to be outside the EU. But there are very special provisions associated with that. The medical devices directive requires the appointment of an authorised rep in the EU to register Class I products and some other directives do not mention the need for either an authorised rep or a responsible person. It is all very confusing, but the general recommendations are: 1. If the manufacturer is outside the EU then appoint an authorised rep to act on your behalf. (This person must be inside the EU to hold the documentation). 2. Formally appoint the authorised rep to be your responsible person and hold the technical documentation, hold a copy of the DoC, and issue the DoC to anyone who needs it. 3. You can, if you want, have your authorised rep (legally appointed) sign the DoC. He is then empowered to bind your company to the claims in the DoC. Alternatively you can sign the DoC yourself. As the DoC is a legal document then it must be signed by someone who is authorised to do so - as said before. If that person is no longer alive or with the company, contract law does not negate the historical validity of contracts because a person is no longer living, or doing something whereby he is no longer authorised to sign documents. Therefore the DoC remains valid for as long as the claims are valid. The signatory signed it on behalf of the company, not as an individual. If a new DoC is required, because the equipment has been modified you cannot get the original person to sign it again because his signed the first version. Besides digging up the dead is illegal in the EU! Therefore the new DoC is signed to bind the manufacturer and that then does not require resigning - unless it is reissued. The question always arises as to who ends up in
Re: UL in Washington Post - Seagull
Several observations on the article and subsequent comments... Seagull analogy--Isn't this description true of the media at large in all forms? I thought that was basically how they sold their wares and made a profit. Once upon a time, it might have been appropriate to bash on UL, even if unwarranted. After all, they had the monopoly on both the standards and certifications for the U.S. Unfortunately, this history is what makes UL an excellent scapegoat for the article. However, now for ITE the UL 1950 standard is basically harmonized with the international IEC 60950. Plus there are many competitors via the NRTL process who can examine and issue the certifications. Of course, many of the standards are still UL, hence they cannot dodge this bullet entirely. My point is that the indictment is not necessarily just against UL, but against some international standards and all agencies authorized to certify against these standards within the U.S. No matter how much we manufacturers complain about UL and other certification agencies for their slowness, costs, and differing interpretive spins on the standards, who really wants a govern- ment agency to assume these duties? I believe there are many documented cases to illustrate that the FDA, FAA, and so on do not necessarily cater to the best interests of the citizenry, but to lobbyists with the deepest pockets. Ever watch 20/20 or Dateline? I also note that no ITE products were mentioned in the article. To my knowledge, the only ITE products recalled in recent times (or ever?) with the "help" of the CPSC were several AC adapters shipped with ITE products they were to power. George Alspaugh - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Article to UL
Hello group, It seems to me that the article in Washington Post, was written by someone who really had not done their homework. It sounded as the article was criticizing UL for not doing proper testing or not being able to write their standards adequately. Like most of the people in the group, I am certainly not a fan of UL for various reasons that are outside the scope of this particular subject, but one has to remember that almost majority of the standards are written with manufacturers directly involved during the generation of the standard. Obviously those of us who are being represented in various standard committee we who are responsible for writing the standard, try to influence the standard as much as we can in our industry favor and test houses such as UL, CSA , BSI, more or less go along with it. As for testing is concerned, all UL engineers as well as their counterparts in other test houses only test the product to the clauses of the standard and they are not allowed to go any further. On top of that, the way that any of these standard are written it is widely open to interpretation so we as test engineers always try to argue with the test house engineer to try to avoid any failure. Another point to bear in mind is that the test house engineers are only human like the rest of us and can make mistake or even overlook at some points. Last but not least, most of us have seen a certified product been slightly modified/altered by someone in our company for an unknown reason and still bears the safety mark without even informing any of the test houses concerned . So I believe we should look at the root casue of the problem and try to improve the situation by (a) be honest with the test houses during testing. (b) by trying to encourage our designers to make the product almost fool proof. © do addition in-house testing that exceeds the requirements of the standard (d) by being a truly responsible manufacturer. Thanks Peter - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
re: Article to UL
As my UL friends are always quick to point out, they are not-for-profit, not non-profit. Not being expert, I assume there is some subtle difference that is lots on the rest of us. A more general question is, why is does UL continue to enjoy special consideration when what they are doing is not unique? Regards, Frank West Sr. Engineer TUV Rheinland NA --- Barry Ma wrote: > > Chaz, Why do they call UL a non-profit organization? > Barry > Anritsu Co. > > From: "Grasso, Charles (Chaz)" > , on 11/24/99 1:23 > PM: > > Forgive a jaded old man but two things jumped out at > me when I read the article. > > 1. "In many other countries, standards are set or > approved by a government entity with industry > involvement. U.S. safety standards, on the other > hand, are set primarily by private industry - either > in independent labs such as UL or by industry > associations or organizations. The CPSC, an > independent regulatory agency charged with > protecting consumers from hazardous products, > imposes federal regulations only when it believes > industry's voluntary efforts are insufficient. " > > Oh Boy. Lets see look like UL is ripe for a > government takeover to me!! > > 2. Many experts interviewed contend that UL's recent > problems can be traced to the way the company is > organized and funded - with more than nine-tenths of > its revenue coming from companies for testing > products. UL also sets industry safety standards - > which it then measures products against - but does > not > charge for that. Lets see - if we reorganize and - > more importantly - change the funding (a euphemism > for taxation) then we'll all be safer!! > > Sorry - Just could not resist.. > > > __ > Open your mind. Close your wallet. > Free Internet Access from AltaVista. > http://www.altavista.com > > > - > This message is coming from the emc-pstc discussion > list. > To cancel your subscription, send mail to > majord...@ieee.org > with the single line: "unsubscribe emc-pstc" > (without the > quotes). For help, send mail to ed.pr...@cubic.com, > jim_bac...@monarch.com, ri...@sdd.hp.com, or > roger.volgst...@compaq.com (the list > administrators). > > > = Frank West Senior Engineer TUV Rheinland of North America NW/Portland OR Office __ Do You Yahoo!? Thousands of Stores. Millions of Products. All in one place. Yahoo! Shopping: http://shopping.yahoo.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
EN60950 3rd Edition?
Hi Ron, For Australia and New Zealand, AS/NZS 3260 closed it's public comment period on 7 Nov 99. Probably to be published early 2000. Also it will probably be numbered AS/NZS 60950 rather than than 3260. Best regards, Kevin > > > Hello out there, > > I have some questions regarding the adoption if IEC60950 3rd Edition. > > 1) Now that IEC60950 3rd Ed. is now out and UL60950 3rd Ed. is out for > review, when will EN60950 catch up and follow IEC60950 3rd Ed.? > > 2) And for that matter, how about AS/NZ 3260 and other 950 derivatives? > > 3) When will the CB Scheme adopt IEC60950 3rd Ed.? > > I'm trying to get a time frame when (if ever) the respective standards will > be upgraded. And, I'm sure the group would be interested to know more. > > Anyone out there who has their ear into what's happening on these > questions? > > Best regards, > Ron Pickard > rpick...@hypercom.com > > > > - > This message is coming from the emc-pstc discussion list. > To cancel your subscription, send mail to majord...@ieee.org > with the single line: "unsubscribe emc-pstc" (without the > quotes). For help, send mail to ed.pr...@cubic.com, > jim_bac...@monarch.com, ri...@sdd.hp.com, or > roger.volgst...@compaq.com (the list administrators). > > > > > > > --- Internet Header > Sender: owner-emc-p...@ieee.org > Received: from ruebert.ieee.org (ruebert.ieee.org [199.172.136.3]) > by spdmgaac.compuserve.com (8.9.3/8.9.3/SUN-1.7) with ESMTP id NAA03479; > Tue, 23 Nov 1999 13:56:40 -0500 (EST) > Received: by ruebert.ieee.org (8.9.3/8.9.3) id NAA08716; Tue, 23 Nov 1999 13:52:01 -0500 (EST) > Subject: EN60950 3rd Edition? > To: emc-p...@ieee.org > Cc: > X-Mailer: Lotus Notes Release 5.0.1a August 17, 1999 > Message-ID: > From: "Ron Pickard/Hypercom/US" > Date: Tue, 23 Nov 1999 11:48:45 -0700 > X-Priority: 3 (Normal) > X-MIMETrack: Serialize by Router on AZPHXN01/Hypercom/US(Release 5.0.1a|August 17, 1999) at > 11/23/99 11:48:46 AM > MIME-Version: 1.0 > Content-type: text/plain; charset=us-ascii > Sender: owner-emc-p...@ieee.org > Precedence: bulk > Reply-To: "Ron Pickard/Hypercom/US" > X-Resent-To: Multiple Recipients > X-Listname: emc-pstc > X-Info: Help requests to emc-pstc-requ...@majordomo.ieee.org > X-Info: [Un]Subscribe requests to majord...@majordomo.ieee.org > X-Moderator-Address: emc-pstc-appro...@majordomo.ieee.org > > Best regards, Kevin Richardson Stanimore Pty Limited (Technology Products Standards, Regulations and Compliance Specialists) Ph: 02-4329-4070Fax:02-4328-5639 Int'l: +61-2-4329-4070 +61-2-4328-5639 Email: k...@compuserve.com (Internet) kevin.richard...@ieee.org (Alternate Internet #1) k...@technologist.com (Alternate Internet #2) 100356,374 (Compuserve) - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: EN60950 Earth Leakage Measurement Circuit.
Duncan, I will take a stab at this since if I really mess up and get flamed by various and sundry members of the group I at least won't know about it until I get back from a four day weekend. Based on my understanding of the requirements there is good news and bad news. The good news is you should not have to meet the tolerance spec; at least not as far as having to use a precision capacitor RATED at 1% tolerance. You need a capacitor with the proper voltage rating that's actual value is between 0.uF and 0.2178uF. Theoretically you can measure the value of a group of 20% 0.22uF capacitors and find one that is within 1% and use it. The word "theoretically" above brings me to the bad news. The distribution of values around the mean tends to be skewed, and it is unlikely you will find a 20% capacitor that is actually 1% because the manufacturer normally preselects and sorts a batch, removing the 1%, then the 5%, then the 10%, and finally the 20% (or whatever tolerances they offer). You will get two peaks in the distribution near the positive and negative bounds. Luckily there is some more good news (or least not terribly bad) if you can live with a four capacitor network. Go back to that bin of 20% caps and start measuring actual values again. This time you are looking for a pair of capacitors whose values add to about 0.44uF. When you find one pair look for a second. connect each pair in parallel (0.44uF), and then connect the two parallel pairs in series (0.22uF). I wouldn't want to design that for a production run product, but a little mix and match for test equipment shouldn't be too bad if you can live with four capacitors. I hope this helps, Paul McCoy duncan.ho...@snellwilcox.com wrote: > Group, > I am trying to construct a simple earth leakage test circuit as in Annex D > of EN60950. I am finding it impossible to find a capacitor for Cs (0.22uF) as > I > cannot find one that is the required value, tolerence and voltage rating. > > Am I missing somthing here? Even if I use a network of capacitors I would have > to use quite a few of them to get the right value! It would appear that the 1% > tolerence that is requested is a bit unrealistic given the value and required > voltage rating. > > Has anybody else found this and if so how was it resolved? Are there any > manufacturers of earth leakage testers who may be able to hint on how they > manage to overcome this? > Any suggestions would be greatly recieved... > thanks, > Duncan. > > - > This message is coming from the emc-pstc discussion list. > To cancel your subscription, send mail to majord...@ieee.org > with the single line: "unsubscribe emc-pstc" (without the > quotes). For help, send mail to ed.pr...@cubic.com, > jim_bac...@monarch.com, ri...@sdd.hp.com, or > roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
