Re: [PSES] AC input test voltages - requirement for grounded phase?

[Doug Powell]

Pat, I find it is far easier if you ask them to justify a non-standard mains configuration.  And stick to your position.  Too often it is easy to get caught in a conflict where the person who is responsible for a product has a test failure and wants to blame the test setup, the standard or anything other than their product. Think about it, they have been working on this project for possibly months, they are heavily invested in their efforts and in a time crunch for delivery.   And you fail it during a routine test. In effect you are calling their baby ugly and you will be blamed for them missing their deadline.   If in the end you do the test with an ungrounded neutral, you will have to include this information in the documentation as a required condition of use. Now the person involved will have to explain this to the client.   Finally, if you check the safety standard associated with the product, you will likely find the required mains wiring. For example, the 61010-1 will require 61326 for EMC testing and 61010-1 has a section on wiring configuration of mains. While having an ungrounded neutral may not be an automatic safety violation, it is not standard. In fact, if ungrounded it cannot be called neutral at all.   Thanks, - doug     From: Pat Lawler Sent: Wednesday, October 23, 2013 7:58 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Reply To: Pat Lawler Subject: [PSES] AC input test voltages - requirement for grounded phase? All, Do the EMC test standards require one of the AC input phases ('neutral' in the U.S.) be grounded?  If so, where can I find an example of this requirement? In the past, I had an experience where EMI test results with an AC supply of 120Vac/0Vac (a source with a grounded neutral) were higher than an AC supply of +60Vac/-60Vac (a source from an isolation transformer.)  I changed my test setup to use a grounded neutral to agree with installation practices. Now I have to justify this to someone, and would like some supporting paperwork.  It's not easy justifying something that may uncover problems. Also, does the AC voltage supplied to homes & small businesses in Europe have a grounded phase, or are both phases above ground? Pat - ---------------------------------------------------------------- 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 <emcp...@radiusnorth.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org> David Heald <dhe...@gmail.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 <emcp...@radiusnorth.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org> David Heald <dhe...@gmail.com>