Folks, EN 60204-1 states
"6.4.1 General requirements PELV circuits shall satisfy all of the following conditions: a) the nominal voltage shall not exceed: 25 V a.c. r.m.s. or 60 V ripple-free d.c. when the equipment is normally used in dry locations and when large area contact of live parts with the human body is not expected; or 6 V a.c. r.m.s. or 15 V ripple-free d.c. in all other cases; b) one side of the circuit or one point of the source of the supply of that circuit shall be connected to the protective bonding circuit; 6.4.2 Sources for PELV The source for PELV shall be one of the following: – a safety isolating transformer in accordance with IEC 61558-1 and IEC 61558-2-6; – a source of current providing a degree of safety equivalent to that of the safety isolating transformer (for example a motor generator with winding providing equivalent isolation); – an electrochemical source (for example a battery) or another source independent of a higher voltage circuit (for example a diesel-driven generator); – an electronic power supply conforming to appropriate standards specifying measures to be –taken to ensure that, even in the case of an internal fault, the voltage at the outgoing terminals cannot exceed the values specified in 6.4.1." The last statement is key to the question. EN 60950-1 defines SELV but not PELV with the main difference being the bonding requirement of PELV which need not be an attribute of the power supply itself. With regards to electronic power supplies most data sheets I have seen state compliance to UL 508 and EN 60950-1 but do not specifically mention anything about meeting SELV or PELV requirements. Some do. The question is it can somehow be assumed that an electronic power supply compliant with UL 508 and/or EN 60950-1 and/or UL listed does in fact meet requirements for SELV? Or is there another standard that also specifically meets the requirements for PELV? Or does this need to be specifically confirmed with the manufacturer beyond the basic UL 508 and/or EN 60950-1 if the data sheets do not specifically claim a PELV rating? Thanks -Dave David P. Nyffenegger, PMP, SM-IEEE Product Development Manager Bell and Howell - ---------------------------------------------------------------- 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]>
