Section 250.64(B) states where exposed and on a surface, a grounding electrode conductor should be protected. If I sleeve an 8 AWG GEC in rigid nonmetallic conduct from the service panel to the crawl, do I have to protect the GEC in the crawl, or is it ok to run the GEC on the bottom of the floor joists without protection to the water pipe? It’s a 100-amp service with 2 AWG copper. Does that last sentence apply to the whole length by 250.64?
Personally, I don’t think it is subject to being physically damaged in the crawl. The crawl is a little less than 3′ high. — A. C.
You are correct in your understanding of this rule. The last sentence of 250.64(B) requires an 8 AWG copper grounding electrode conductor to be protected from physical damage by installing it in rigid metal conduit, rigid nonmetallic conduit, intermediate metal conduit, electrical metallic tubing, or cable armor, and no exceptions to this requirement. If the conductor is a 6 AWG, it could be judged as not subject to physical damage in the installation you’ve described in the question. As I see it, the solutions are to either size up to 6 AWG or protect it with one of the methods specified in 250.64(B). As always, consult the local approving inspector/AHJ for any local requirements or interpretations. I hope this helps with your question. — Michael J. Johnston, CMP-5