Mark, If you look at NEC 250.104(C), you'll find that you have to bond structural metal that is "likely to become energized". The phrase "likely to become energized" is not defined, and is up to the AHJ. I would guess most AHJ's would consider the second metal plate to already be bonded since it is electrically continuous with the first metal plate, because they're touching. I also doubt they would consider it "likely to become energized" because you bonded the first metal plate. Just my opinion.
-Hans -----Original Message----- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Mark Frye Sent: Wednesday, July 25, 2012 7:29 PM To: RE-wrenches Subject: [RE-wrenches] Grounding - Exposed Metal Part A bare metal plate is connected to a conduit which serves as an equipment ground. The plate is grounded and needs to be grounded because it could become energized both by being contact with the conduit which could become energized and also by coming into contact with the current carrying conductors themselves. A second bare metal plate touches the first plate but could not come into contact with the current carrying conductors. True or false, the second plate does not have to be grounded (bonded to the first plate) because the first plate is already grounded and therefore could not cause the second plate to become energized? Any Code references to support your opinion? P.S. I believe: "false", the second plate must be bonded to the first plate because it may become energized by the first plate regardless of whether or not the first plate is actually grounded, but I can't find references in the Code to support this. Mark Frye Berkeley Solar Electric Systems _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
