Didn¹t see any responses to this one, so taking a shot at it. Can¹t speak to the commercial specs, but from a common sense safety point-of-view, if it is possible for power to short to the table, then the table needs to have a safety ground connection. That connection should be the same as the safety ground coming to the UPS, following the same rules. Ken Javor Phone: (256) 650-5261
From: "Darnel, Gary" <[email protected]> Date: Tue, 20 Nov 2012 06:42:09 -0700 To: "[email protected]" <[email protected]> Conversation: Question about HiPot Testing and grounding Subject: FW: Question about HiPot Testing and grounding Hello Group, I don¹t know who to ask this question to, so I will pass it by the group. The question I have is about HiPot testing and grounding. We manufacture a table to which we attach a PDU--power-distribution-unit (basically a power bar, but safety certified to EN60950). The frame of the table is metal, and the surface of the table is made of Trespa, a non-conductive material. The PDU is attached to the metal frame of the table, under the table surface. We gang these tables together to make larger work surface on which laboratory instruments are operated. The tables are bolted together. We will place a UPS under the table, and plug the PDU into the UPS. The cabling from the PDU is routed along the metal structure to the UPS. I am not aware of a specific safety standard to apply. I am familiar with EN61010 and the Canadian / USA equivalents. My question is this: the table frame is conductive, so should we ground the tables to one another with #14AWG ground wires, and then ground the table frame back to building ground? Or back to the UPS? Do we need to perform a HiPot test on this system (UPS, PDU, Table)? Do we need to ensure ground bond conductivity to 0.1ohm or less on the metal structure? We assemble such tables and systems at customer sites, and in the past it was our practice to perform HiPot and Ground Bond tests on the table structures before they left our facility. But that was also because we built-in our own power outlets into the tables. These power outlets provided inherent grounding of the table frame, and the HiPot test confirmed safe wiring of the outlets. We no longer integrate our own outlets, instead, using off the shelf power distribution units (PDUs). FYI, the PDU¹s are 115VAC / 15A, typically 6 outlets each. We also use European version equivalents, but at 230VAC. Any assistance or comment would be appreciated, Many thanks, Gary - ---------------------------------------------------------------- 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]> - ---------------------------------------------------------------- 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]>
