True, John. But even in the UK, this would rely on too many opportunities for incorrect connections over which the user has no control. Also, I am not sure that I would like to rely on the grounding of the Neutral conductor, as the point at which it is grounded could be a very long way away from the point of connection of the apparatus; sufficient, I am sure, for there to be a measureable voltage between Neutral and Ground.
Regardless, two-pole disconnection is obviously preferable. Best regards Neil R. Barker CEng MIET HonFSEE MIEEE Manager Quality Engineering e2v technologies (uk) ltd 106 Waterhouse Lane Chelmsford Essex CM1 2QU UK Tel: (+44) 1245 453616 Fax: (+44) 1245 453571 Mob: (+44) 7801 723735 P Please consider the environment before printing this email. From: John Woodgate [mailto:[email protected]] Sent: 14 September 2007 13:17 To: [email protected] Subject: Re: I O power switch In message <[email protected]>, dated Fri, 14 Sep 2007, "Barker, Neil" <[email protected]> writes: >EN60950-1:2006 states, in Clause 1.7.8.3, Where symbols are used on or >near controls to indicate ON and OFF conditions, they shall be the line >| for ON and circle O for OFF. It is permitted to use the symbols O and >| to indicate the OFF and ON positions of any primary or secondary >power switches, including isolating switches. > >Nowhere does it state that these have to be two-pole switches, but if >they are isolating switches, then they should be two-pole switches. But what about the requirements of 3.4.6 in respect of double-pole switching? The 'except' in the first paragraph doesn't apply in countries where the 'Schuko' or 'Europlug' mains plugs are used, because they are reversible. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk There are benefits from being irrational - just ask the square root of 2. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK Sent by E2V TECHNOLOGIES PLC or a member of the E2V group of companies. A company registered in England and Wales. Company number: 04439718. Registered address: 106 Waterhouse Lane, Chelmsford, Essex, CM1 2QU, 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 ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
