My AHJ is making me ground the Enphase inverters AND use a separate equipment ground for modules / mounting rails.
The panel frames are grounded to mounting rails via WEEBS, rails are grounded together using WEEB lay-in lugs and copper wire, this ground wire makes its way to AC panel gnd bar, where it is connected to ground rod via grounding electrode conductor, as normal. AHJ insists I also install dedicated continuous ground wire from each Enphase inverter gnd clip directly to the building GEC or to the ground rod itself. Mind you, the inverter enclosure, to which the gnd clip is attached, is already grounded to the mounting rails via WEEBs. So what I have done is created a parallel ground between the mounting rails and the GEC, a.k.a a ground loop, a.k.a. a current divider. Short circuit current from the Enphase is going to be split between the two paths to ground. The only way this grounding scheme makes any sense to me is if the inverters were totally isolated from the rails using a non-conductive tape or washer between the rail and inverter at point of attachment. Just removing the WEEBS would not isolate the two. My AHJ is basically trying to apply the grounding rules of a string inverter (dedicated gnd directly from inverter to GEC) to a micro-inverter, but I feel this method, aside from redundancy and T $ M, is little short in the "best practice" or "safest" categories. I'd be interested in other takes on this. Thanks. Kirk Herander Vermont Solar Engineering 802.863.1202 NABCEP(tm) Certified Solar Installer NYSERDA-eligible Installer VT Solar Incentive Program Partner _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] 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
