Pierre, Various engineers within a test house evaluate products differently due to their own interpretations. The 60601 series of standards have not been designed to accomodate the high voltages occuring within switching power supplies. The standards are currently being worked on to incorporate similar requirements as for the IEC 60 950 requirements - here working voltages are based not on only on mains voltage but working voltages anywhere within the equipment.
Best is to take the previously approved power supply and show it to the test house. Tell them that you wish to have the same service. However, I also recommend that you obtain the working papers from your local IEC Committee for Medical Equipment and try to design the power supply to meet the future requirements. Regards, 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: Pierre SELVA [mailto:[email protected]] Sent: Monday, July 29, 2002 7:20 PM To: Forum Safety-emc Subject: IEC 60601-1 Hello, As all the safety standards, IEC 60601 defines the creepage and clearance distances regarding the working voltage of the considered insulation. In a switching power supply, designed for medical product, one of my customer has designed the creepage and clearance distances to be compliant with the rated voltage, which is 230 V. When one of the most known test house has reviewed the product, engineer said that the creep. and clear. were not good, due to the voltage between primary and secondary which is, at some location, about 440 V rms. This voltage implies 16 and 9 mm distances. These distances are very hard to obtain in the PSU (size of a PSU for Personal computer) and mainly the optoisolators are dimensionned to comply with it. So, my customer had a look on other PSU certified to IEC60601 by very known test house, and he was surprised to see that the creep. and clear. were designed to meet 230V requirements, and not 440Vrms (the PSU had such a voltage inside). How can we explain this situation, and is there a solution to have a compliant PSU with insulation designed to meet 230v distance requirements. Thanks to all, Pierre ------------------------------------------- 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: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] 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. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] 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"
