Kim, I would guess that your 385 Vdc is the output of a power factor correction module. These do not usually provide any galvanic isolation (as you state), so the 385 V is with respect to the mains input. We generally consider this part of a circuit to be a "primary circuit" or "circuit derived from mains" and have had products independently assessed for EN, UL, and CSA versions of standards as well as gaining IEC CB reports on this basis. There is not a great difference between 385 Vdc and the peak value of 240 Vac; well about 45 V in fact. I would recommend that you use 385 V as the working voltage as it is the 'safe' option and shouldn't make life unduly difficult for you.
Best regards Neil R. Barker CEng MIEE FSEE MIEEE Manager Compliance Engineering e2v technologies (uk) ltd 106 Waterhouse Lane Chelmsford Essex CM1 2QU UK Tel: (+44) 1245 453616 Fax: (+44) 1245 453410 Mob: (+44) 7801 723735 From: Kim Boll Jensen [mailto:[email protected]] Sent: 07 October 2005 09:00 To: EMC PSTC Subject: working voltage Hi all In EN 61010-1 the creepage and clearance in table 4 is based on a "Voltage line to neutral". Is this a working voltage or is it just the mains supply ? The reason I ask is that I'm involved in a switch mode PSU which have a 385 Vdc at the primary of the switch transformer. The 385 Vdc is galvanic connected to the mains and as I see it, not "a circuit derived form mains circuit". So shall I use 385 V or just 240 V for the transformer creepage and clearance ? Best regards, Kim Boll Jensen Bolls Rådgivning Ved Gadekæret 11F DK-3660 Stenløse Tlf.: 48 18 35 66 Fax: 48 18 35 30 Mobil: 22 99 69 91 E-mail: [email protected] web: www.bolls.dk - 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/listserv/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
