I'm running into a dilemma. Not being a Safety Engineer myself, but rubbing elbows with them...
On a piece of ITE equipment, I need some surge suppression for worldwide markets with one annoying requirement for 4 kV, otherwise just 2 kV line to earth, and using either plugable cords or permanent connection, whichever is worse. Now the Safety guys tell me that MOV's alone cannot bridge the insulation (Basic or Functional, I forget.) between primary and earth, when using one of power cable options mentioned above. But a proper qualified (GDT) gas discharge tube can do the bridging. So we figured to use them in series. On a quick and dirty bench test it works to 4 kV. Then the Safety guys pull out the rest of the story and point out 5.2.2 which seems to indicate that the GDT is to meet the Hi-Pot test, 1500 vac. Previously, section, 1.5.9.4 (?) indicates that the surge protection devices can be removed during the Hi-Pot test. But now I have a Surge suppression circuit that has to withstand the same Hi-Pot as the rest of the board. Question is how does a surge protection circuit protect the board when it has to meet the same Hi-Pot test? In other words, when a surge comes along, which is going to break over first? The surge protection or the board? Is the purpose of surge suppression is to keep the clamped voltage below a problem level? What am I missing in this? Thanks... - Bill - ---------------------------------------------------------------- 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://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]>
