1

I’m in Hawaii. The G.C./engineers have told previous electricians that they want the bare ground coming up through slabs to building steel to be in a short piece of rigid conduit for protection of the ground wire.

I'm sure this causes a choke on the ground which means the mains may never trip, etc. There are no grounding bushings on the conduit. Is this an approved means in Hawaii?

  • The choke effect would be insignificant with short sleeves, and I am sure it would still clear a fault, but to be code compliant, you have to use the grounding bushings with a ferrous metal conduit. – batsplatsterson Oct 10 '18 at 19:47
  • A short sleeve ? What do you consider short and I guess your sure of no problems ? – user91920 Oct 13 '18 at 4:08
4

You want Schedule 80 PVC, not a metal rigid conduit

Assuming that the engineers want the grounding electrode conductor protected from physical damage, then the tool of choice for this job is Schedule 80 PVC conduit, as you are correct that putting a single conductor in a ferrous (steel) conduit will cause a "choke" effect that impairs the ability of that conductor to carry current. Either that, or if ferrous conduit is required, then use a conduit grounding clamp, jumper, and lay-in tap lug at each end to bond the conduit to the conductor -- this suppresses the choke effect.

2

I've been seeing people ask for this lately because of copper thieves going around cutting grounding electrode conductors, thinking they are "safe" free copper when they see that it is bare. If they can't see it, they don't know what's in the conduit and rarely want to take the chance of cutting a live wire so they leave it alone, hence the PVC would be fine.

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