Years ago I worked for a company that produced an ITE product. The power supply manufacturer had sent a batch of power supplies that the nut was not properly tightened on the PE conductor to chassis. We actually found the problem during our production line ground bond testing. After some testing we found an increased leakage current but still within the limits of the standard.
Not quite in the realm of the original question, but it shows that proper line testing can find errors that could result in issues in the field. Josh From: Scott Aldous [mailto:[email protected]] Sent: Monday, November 10, 2014 10:40 AM To: [email protected] Subject: [External] Re: [PSES] Open Protective Earth Conductor Fault Standards typically apply touch or leakage current limits to plug-connected products. I believe that potential for an unreliable ground connection at the receptacle the product plugs into is at least as important a concern as the potential for faults inside the product itself. For example, in an old house in the USA with 2 prong outlets, it is common for the homeowner to simply use "cheater plug" adapters to avoid having to connect the ground pin at all. This could well be considered outside the intended use, but people will do it anyway, at least for a consumer product. On Sun, Nov 9, 2014 at 11:00 PM, John Woodgate <[email protected]<mailto:[email protected]>> wrote: In message <[email protected]<http://wellman.com>>, dated Sun, 9 Nov 2014, Ronald Wellman <[email protected]<mailto:[email protected]>> writes: I would like to know if anyone has had an experience where a product actually experienced an open protective earth conductor fault after it left the factory. If you have, what was the Root Cause? Two cases: - failure of weld of PE connection stud to metalwork; - enclosure fixing screw severed PE connection in mains cable internal to the product. Both products were small and no excessive touch current occurred. I ask this because there are various standards that allow you to waive the touch current test because of the product connection means to the building branch circuit. Because of this, I would like to know who has actually experienced a touch current hazard and under what conditions. Regardless of what the standard allows, I would measure and minimise touch current, and as far as possible make the internal PE connection secure (i.e. screw or nut and bolt, no welded stud). -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk<http://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]<mailto:[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]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher: <[email protected]<mailto:[email protected]>> David Heald: <[email protected]<mailto:[email protected]>> -- Scott Aldous Compliance Engineer Google 650-253-1994 [email protected]<mailto:[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]<mailto:[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)<http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher <[email protected]<mailto:[email protected]>> David Heald <[email protected]<mailto:[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]>
