[RE-wrenches] Rooftop wiring methods between multiple subarrays

[Nick Vida]

Max, 

I'm with Bill Brooks, among others on this one. 
You are risking more than you might want to realize by bonding with mini (hanger) straps. Without an excelent path to ground through you equipment ground touching all frames on your array, you are risking static charge that can attract lightning. Also, your negative conductor is bonded to ground in your inverter, and if that is a better path to ground than your mini straps, then the lightning current might want to pursue that path and totally fry your system. You can find an interesting report by arco on a lightning study shared here on the list by mr. joel davidson of los angeles.
my choice is to run emt with connectors and ground bushings and run ground wire through the emt. I personally like to put only a connector and a plastic bushing on the other side because that stick is bonded, but that is maybe arguing against an article 250 code reference. I dont worry about running bare copper through the emt unless it is 6 awg or greater, and i would need to grab the NEC, but i think that is the cutoff (however i have never considered galvanic incompatibility before this thread).
it is great that you are seeing eye to eye with your AHJ, but i would rethink that one.

nick vida


      
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