Hi Brian:
Hmm. I wonder if UL knows what UL knows. Mr. Flore Chiang of UL's Taiwan office has given several papers at the PSES Symposia on the physics of clearance, creepage, and solid insulation breakdown. These are classic papers and should be studied by all product safety professionals. Mr. Chiang has presented his papers to the IEC TC108 committee so that the committee can prepare insulation requirements that are in concert with the physics of electrically-caused breakdown. Without doing anything to improve my memory, I believe d.c. is easier on all of the insulations than is a.c. Mr. Chiang's papers discuss the differences and why. Richard Nute Product Safety Consultant Vancouver, Washington, U.S.A. > -----Original Message----- > From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf > Of Brian Oconnell > Sent: Wednesday, November 30, 2011 9:45 AM > To: EMC-PSTC@LISTSERV.IEEE.ORG > Subject: UL assessment of plastics - DC vs AC > > > Received a newsletter from UL. Said that they are looking > into updating > standards to account for DC di-electric withstand vs AC. I > can understand > that the physics of dc arcing and tracking could be different > from ac, but > why would the dc di-electric withstand be more onerous than ac? > > Perhaps they are mixing IR and di-electric withstand, which cannot be > considered a similar test. > > 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 <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://product-compliance.oc.ieee.org/ Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ 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 <emcp...@radiusnorth.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
