In message <[email protected]>, dated Thu, 27 Mar 2008, "Lyons, Jim" <[email protected]> writes:
>One issue would be the touch current allowed for Class II products. >Under IEC 60065 it is 0.5 mA, and under IEC 60950 it is 0.25 mA. Actually, it's 0.7 mA peak: the current is often nowhere near sinusoidal. > >I would be interested in hearing what others think about that. Is the >touch current requirement of IEC 60950 unnecessarily severe? Quite possibly; after all, IEC 60065 has been around for very many years, and if there were a problem with touch current, customer complaints would have resulted in a reduction. The 0.7 mA value is probably derived from what was practicable with a mains transformer. Since many countries use reversible mains plugs, the hot end of the primary winding may be close to the core or, for that matter, close to the electrostatic shield between primary and secondary windings. While the core might be allowed to float, the shield really must be connected to some accessible conductive parts, if there are any. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk Murphy's Law has now been officially re-named The Certainty Principle John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - 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/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
