Richard, Thanks for the file. As usual, it clearly explains the conditions and solutions.
Our products can be powered by any 230Vrms power system not requiring a grounded neutral and the polarity can be changed, we can use dual pole breakers to avoid the potential hazard to service personnel. This has been our company's practice for over 20 years but I wasn't sure where the concern came from. Now I have a better understanding. Thanks again. The Other Brian From: Richard Nute [mailto:[email protected]] Sent: Friday, November 04, 2016 2:59 PM To: Kunde, Brian; [email protected] Subject: [BULK] RE: [PSES] AC Mains Outlet fuses or daul pole breaker?? Importance: Low Hi Brian: In 1998, I wrote a column, Technically Speaking, in the Product Safety Newsletter that addresses this topic. See attached. (Since the listserver does not accept attachments, subscribers should e-mail a request to me.) Best regards, Rich From: Kunde, Brian [mailto:[email protected]] Sent: Friday, November 04, 2016 7:38 AM To: [email protected]<mailto:[email protected]> Subject: [PSES] AC Mains Outlet fuses or daul pole breaker?? Greetings Experts. If we send 230Vrms out of a product to power an external device through an IEC Outlet connector and we need to provide Overcurrent Protection for this port internal to our device, can I use two fuses or do I have to use a double pole circuit breaker? Since our product can be used in a 220-230 Vrms power system which cannot guarantee polarity on the plug (such as Europe) or that the neutral will be grounded (some North American power systems for example), we have to have over-current protection on BOTH sides of the line (all current carrying conductors). But when we supply power externally to another device, it is possible that one fuse could open and the other side of the line is HOT to Earth. Someone working on the external device could put a meter across the line as see there is no voltage and assume the AC mains is OFF not knowing that one side of the line it still HOT to Earth. This could cause a hazardous condition. SO, this is the reason for my question. If our device supplies power externally to another device, can we use fuses which could cause the hazardous condition I explained above, OR must we use a Double Pole Circuit Breaker which opens all HOT conductors simultaneously? If I must use a breaker, what standard or rule dictates this requirement? OR is this even a scenario we have to be concerned about? Since the external device has a warning label to disconnect power cord before servicing, is this even something to be concerned about? BTW, my product is Laboratory Equipment (UL/IEC 61010-1) to sell on a worldwide market. Thanks, The Other Brian ________________________________ LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. Thank you. - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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If you received this by mistake, please destroy it and notify us of the error. Thank you. - ---------------------------------------------------------------- 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]>
