PVC-GRC-PVC underground

[sparky90807@yahoo.com]

I have 3 - 6” PVC conduits coming out of a underground vault running around 400’ to another underground vault, the owner wants 200’ of wrapped 6” GRC in the middle of the run, keep in mind this is all concrete encased.
My inspector is telling me this is not legal because the GRC would need to be bonded to ground
Is this correct?
How would there be a potential for shock/lightning when the GRC is around 200’ away in each direction?
thank you

 

[steve66]

I think he is basically right. 250.86 requires metal raceways to be bonded to ground. it has an exception for metal elbows installed at 18" below grade, or in 2" or more of conduit.

Unfortunately, there isn't any similar exception for a straight run of GRC in concrete. Possibly just because nobody ever saw a need to do this.

I believe you could run a properly sized bonding conductor connected to the GRC with a listed fitting, run on the outside of the PVC conduit, and connected to ground at the first enclosure.

 

[GoldDigger]

I think he is basically right. 250.86 requires metal raceways to be bonded to ground. it has an exception for metal elbows installed at 18" below grade, or in 2" or more of conduit.

Unfortunately, there isn't any similar exception for a straight run of GRC in concrete. Possibly just because nobody ever saw a need to do this.

I believe you could run a properly sized bonding conductor connected to the GRC with a listed fitting, run on the outside of the PVC conduit, and connected to ground at the first enclosure.

Or maybe run inside the PVC if you can figure out a set of fittings that could get it there.

 

[Cow]

Why does the owner want GRC in the middle of the run, when it's already concrete encased?