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 <j...@jmwa.demon.co.uk> wrote: > In message <000001cffc76$850f8100$8f2e8300$@wellman.com>, dated Sun, 9 > Nov 2014, Ronald Wellman <rwell...@wellman.com> 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 > 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 < > emc-p...@ieee.org> > > 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 <sdoug...@ieee.org> > Mike Cantwell <mcantw...@ieee.org> > > For policy questions, send mail to: > Jim Bacher: <j.bac...@ieee.org> > David Heald: <dhe...@gmail.com> > -- Scott Aldous Compliance Engineer Google 650-253-1994 scottald...@google.com - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> 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 <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
