Kevin,
Note also that here in the US, in Canada, and other countries with power systems similar to that of the United States, nominally 120 V to ground, 60 Hz, residential single phase, 3-wire power is identified as a "120/240 V ac, single phase, 3-wire" system. This consists of the two live ungrounded conductors located at the ends of the service transformer secondary (i.e., L1 and L2), and the grounded neutral (N), which is the center-tap of the transformer. This does not mean that you necessarily use either 120 V or 240 V, but often use both in the same appliance. Examples include electric clothes dryers that use 240 V for the heating element and 120 V to spin the barrel, and industrial service equipment such as telephone wireless base stations that may use 240 V for the main electrical loading, but have a 120 V convenience receptacle for powering service personnel's tools. Appliances that simultaneously utilize both 240 V ac single-phase loads and 120 V ac loads have electrical ratings like "120/240V ac, 3 wire, XX A, 60Hz." For these types of products, it is important to use "3 wire" in the electrical rating to distinguish it from a product that uses either 120 V or 240 V at the same input terminal. Best regards, DON GIES, NCE ALCATEL-LUCENT SENIOR PRODUCT COMPLIANCE ENGINEER BELL LABS - GLOBAL PRODUCT COMPLIANCE LABORATORY Murray Hill, NJ 07974-0636 USA don.g...@alcatel-lucent.com MEMBER, ALCATEL-LUCENT TECHNICAL ACADEMY -----Original Message----- From: Kevin Robinson [mailto:kevinrobinso...@gmail.com] Sent: Friday, January 27, 2012 11:57 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: Is this common knowledge - Electrical Ratings Thanks everyone for your response. Everyone who responded to me on the forum and privately was correct that 120-240V indicates a range, and the product can operate at any voltage over that range. 120/240V indicates that the product can only operate at those specific voltages (plus tolerances). As for the "general public", I was actually quite surprised. I asked several people that I know, many of whom freely admit they "don't know how electricity works". Every person I asked knew that 120-240 was different from 120/240 and they were able to guess a range vs either/or. The "general public" was pretty clear on 120-240V saying they would just plug it in and it would work, however they were confused when faced with 120/240, some said they should look for a voltage selector switch, others indicated they would need some sort of adapter, and a few people said just plug it in and it will work. Thanks again for your responses, Kevin - ---------------------------------------------------------------- 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 < <mailto:emc-p...@ieee.org> emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: <http://www.ieee-pses.org/emc-pstc.html> 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/> http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: <http://www.ieee-pses.org/> http://www.ieee-pses.org/ Instructions: <http://listserv.ieee.org/request/user-guide.html> http://listserv.ieee.org/request/user-guide.html List rules: <http://www.ieee-pses.org/listrules.html> http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas < <mailto:emcp...@radiusnorth.net> emcp...@radiusnorth.net> Mike Cantwell < <mailto:mcantw...@ieee.org> mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: < <mailto:j.bac...@ieee.org> j.bac...@ieee.org> David Heald: < <mailto:dhe...@gmail.com> dhe...@gmail.com> - ---------------------------------------------------------------- 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://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://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>
