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"
