Logic error - the requirements of cl 2.5 are connected by 'OR' logic. Note that one of the choices is "b) a linear or non-linear impedance limits the output in compliance with Table 2B. If a positive temperature coefficient device is used, it shall pass the tests specified in IEC60730-1, Clauses 15, 17, J.15 and J.17; or"
Assuming that this is for a mains-isolated LPS output, we can say that this is not related to overcurrent protection for branch circuits, and will also assume that another overcurrent protective device is being used to satisfy NEC 240.10. If the above is true, then a PTC, that is certified as a current interrupt where the end-use meets its conditions of acceptability, should be acceptable if a short or overload meets the limits of table 2C. I have used 'auto-resetting' PTCs to meet the requirements of both UL60950-1 and UL1012, their use IS, in fact, allowed. But I have also 'encouraged' the designers to include other series impedances that will also provide ultimate current limits not dependent on the PTC. luck, Brian From: [email protected] [mailto:[email protected]]On Behalf Of Jim Eichner Sent: Tuesday, June 17, 2008 2:24 AM To: [email protected] Cc: Jim Eichner Subject: 60950-1:2006 clause 2.5 - Limited power sources If an overcurrent protective device is used, it is not allowed to be auto-resetting. Why? Just above this requirement is an allowance to use PTC's and they auto-reset, so why the bias against auto-reset breakers? Thanks, Jim Eichner, P.Eng. Compliance Engineering Manager Xantrex Technology Inc. e-mail: [email protected] web: www.xantrex.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
