John, Not wishing to throw a spanner in the works - l have to mention different earths can be at different potentials. Strange but true!
Regards Ian White Compliance and Reliability. -----Original Message----- From: John Cochran [mailto:[email protected]] Sent: 08 September 2014 16:04 To: [email protected] Subject: Re: [PSES] UL 60950-1 clause 2.2.3 It appears that I can only meet this requirement for outdoor enclosures by either using a Class 2 power supply, or require the installer to use the external ground connection in addition to the internal PE ground. The system is safe under normal conditions, but only has hazardous voltages on the enclosure when the PE ground is broken. Are there any opposing opinions? John Cochran STRONGARM Designs 425 Caredean Drive Horsham, PA 19044 PHONE: 215-443-3400 X193 FAX: 215-443-3002 -----Original Message----- From: John Woodgate [mailto:[email protected]] Sent: Monday, September 08, 2014 2:42 AM To: [email protected] Subject: Re: [PSES] UL 60950-1 clause 2.2.3 In message <[email protected]>, dated Sun, 7 Sep 2014, Rich Nute <[email protected]> writes: >I believe the authors of 60950-22 expected that user-accessible parts >would comprise SELV circuits rather than grounded parts. See 2.1.1 and >2.2 in 60950-1. > >Grounded parts would be subject to 5.1 in 60950-1. Thank you. So what can the OP do? Does this need to be taken into account in a revision or replacement of 60950-22? -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk Quid faciamus nisi sit? John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - ---------------------------------------------------------------- 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]> - ---------------------------------------------------------------- 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]> _____________________________________________________________________ Spirax-Sarco Engineering Plc. This e-mail has been scanned for viruses by Verizon Business Internet Managed Scanning Services - powered by MessageLabs. For further information visit http://www.verizonbusiness.com/uk - ---------------------------------------------------------------- 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]>
