PV frame ground wire touching composite shingle roof?

echothechoth Posts: 3Registered Users
Oh, no, another dreaded grounding discussion.   :/  I've read and read so many grounding discussions but have not seen any reference to whether PV frame GEC going directly to the ground rod from the roof should or should not touch composite shingle roofs per NEC.  I've driven around town and see commercial installations where the #6 wire DOES touch shingles until it reaches the eaves where it is run through pvc until it hits the ground rod.  Installations where the ground wire is not visible at all from outside the building coming from the roof area, I am assuming is run with the rest of the wiring through conduit to the building interior and possibly PV combiner and to the rod from there.  My solar electrician nephew says he has worked on commercial solar installs, IKEA, and the large bare ground wire, something like a 1/0 or 2/0, was laid across the flat building roof until it hit the conduit.  This is one of my last steps of the current install as I expand my existing 16 yr-old ground mount system with an additional 3.6 kw roof-mounted panels.

Thanks

Comments

  • BB.BB. Posts: 27,780Super Moderators admin
    Not sure code says anything--But I would avoid having the ground wire touch the shingle--Asphalt and Wood shingles can be pretty fragile and the wire could damage an asphalt single over time (shingles get soft when hot, also could knock "fine rock chips" off of the shingle--Rock protects asphalt against sun/weather--Pressure from ground wire/movement from wind/etc. on wire cause mechanical damage to shingle), or possibly stain a wood shingle with copper (wood shingles are a fire hazard out west here--So they are not used much anymore).

    But I would not be worried about electrical issues (ground wire should be at "zero" potential).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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