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Per the 2011 NEC, are perimeter fences around PV farms required to be bonded to the grounding electrode system of the MV transformer?

Question asked by earlidean on Jan 22, 2017

I am not sure if the perimeter fence is required to be grounded by bonding to the ground rings around the MV transformers or not.  The output is proposed to be 23 KV, installed underground with direct buried single conductor shielded cables 3 feet deep.  There would be no exposed conductors above ground except for the nominal 1000 volt DC conductors cable tied under the PV modules.  The fence will maintain a minimum of 15 feet from these exposed live conductors.


I have attached an essay from NESC on the subject.  Our PV farm will be privately owned, and therefore not under the purview of NESC.  The NEC in 250.190 requires fences around MV electrical facilities to be grounded, but the exception is for instances where the metal part (fence?) is out of reach.  Or is the meaning: that the metal enclosure of the energized part is out of reach of the ground (earth)?  I may be reading too much into this exception.   It seems clear in the NESC article the fence would be required to be grounded if the PV farm was owned by the utility, through the NESC, but I am unsure if the NEC requires it for a private PV farm.