I agree with Peter, per the standard, and most IEC product standards, you need two levels of protection from electric shock. In your case the y-caps provide one level (basic insulation) and the earth connection provides the second. As long as your earth path, between primary and secondary (I am assuming your secondary is connected or coupled to earth), will pass the Earth continuity test then it is unreasonable for the agency engineer to enforce reinforced dielectric requirements on the basic insulation Y-caps and you should be allowed to lift them during the test. You need to politely ask him to check with his superior on this one!
I have not worked with 950 in many years now but I do remember that the Nordic agencies were requiring reinforced spacing and insulation between primary and earth for the reasons Peter cited. If you plan on selling in this region you should check all of the National deviations and maybe contact DEMKO (part of UL now) to see if this is still required for the Nordic countries................ -----Original Message----- From: Peter Merguerian [mailto:pmerguer...@itl.co.il] Sent: Thursday, August 22, 2002 1:09 PM To: 'Brian O'Connell'; emc-p...@majordomo.ieee.org Subject: RE: electric strength test Brian, Your interpretation of the standard and application of the test between pri-sec is acceptable. You need to speak to a higher level person in the agency who is an expert! Please be advised that some countries do not have a reliable earthing system. Many end-product manufacturers design their equipment such that the power supply has double insulation or reinforced insulation between pri-earth. Norway is a good example. You may come across some distributors in Norway asking for DI or RI between pri-sec, even for Class 1 power supplies. Good luck at the agency! This e-mail message may contain privileged or confidential information. If you are not the intended recipient, you may not disclose, use, disseminate, distribute, copy or rely upon this message or attachment in any way. If you received this e-mail message in error, please return by forwarding the message and its attachments to the sender. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: + 972-(0)3-5339022 Fax: + 972-(0)3-5339019 Mobile: + 972-(0)54-838175 http://www.itl.co.il http://www.i-spec.com -----Original Message----- From: Brian O'Connell [mailto:boconn...@t-yuden.com] Sent: Thursday, August 22, 2002 3:57 PM To: emc-p...@majordomo.ieee.org Subject: electric strength test Good People of PSTC: I am attempting to comply with both the letter and spirit of 60950:2000, cl 5.2. Note that 5.2.2 allows for separate testing, according the type of insulation required. When testing a (class 1) power supply, the withstand level for primary to chassis is Basic; and for primary to secondary is Reinforced. Typically, I will apply approx 2500vdc for Basic and 4300vdc for reinforced. But to pass primary to secondary test, 60950 says that I can allow for following: "care is taken that the voltage applied to the reinforced insulation does not overstress basic...". Also "to avoid damage to components or insulation which are not involved in the test, disconnection of ICs or the like and the use of equipotential bonding are permitted." For Pri/Sec testing, the screw connecting the Y-caps to the chassis is removed, insulation is inserted between the screw insert and chassis. A (new) agency engineer says that inserting a piece of insulator defeats the purpose of the test. For class 1 construction, it is just not possible for me to pass 4300vdc test levels without inserting my little piece of valox, unless I physically remove all Y-caps (and the unit will not operate reliably with y-caps). I have inspected units from several other companies and have determined that it was not possible to have ever passed pri-sec test levels without isolating these circuits. What test technique generally accepted by your agency engineers? TIA. R/S, Brian O'Connell Taiyo Yuden (USA), Inc. ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list" ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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