Dunno if this is understood. For typical component SMPS per 60950 or 62368, evaluation of the transformer is same regardless of the material thermal class required. For the over 100 power supply submittals done last ten years, did not see any significant difference in assessments whether class 105 or class 220 (I had no class, but the transformer did).
Would like to know more about the " some fairly specialized in-product testing and additional safeguards" Brian From: Brian Gregory [mailto:[email protected]] Sent: Thursday, May 19, 2016 8:45 AM To: [email protected] Subject: Re: [PSES] Transformer insulation class To simplify; I often saw transformers declared class A pretty simply w/o any record of an independent evaluation or certification. Higher classes are another matter completely. To get a transformer approved for operation above the limits for class A, one needs a separate evaluation. I'll skip detail over which standard or process could be used, simply to assert that you'll need to talk to your NRTL or NB about this... unless the vendor has a class B equivalent. You'll need either: a class B transformer, a new certification for the transformer in use to class B, or some fairly specialized in-product testing and additional safeguards. Any way you take that advice, you're going back to your NRTL or NB... Colorado Brian - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) 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]>
