National Electrical Installation Standards

Standards as High as Your Own

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Friday, February 1, 2019

Question:

Re: CQD answer published Wednesday, January 23, 2019 - Concrete Hole Raceway

Regarding the CQD for 1/23/2019 about the concrete wall hole-raceway:

My guess is that David's pronoun reference for "doing this a long time" meant that he had been doing electrical work a long time, not using holes in concrete as raceways. =}) Those darn pronouns can be pretty slippery.

In any case, this would have to be an installation which an inspector used their 90.4 authority to accept as safe. It certainly could be, as long as an equipment grounding conductor properly bonds the metals on both sides as required in Article 250. The concrete hole could be acceptable as a raceway under 90.4 since it is fully non-combustible. I have indeed received just such an approval (ahead of construction of course) for a case of an old exterior service being refed by a new exterior service - the multi-hundred amp feeder (1200 as I remember it) was run in just this manner.

The undisussed concern I would have is if one side of the wall of David's subject is exterior : How is the installation protected from water intrusion and corrosive damage?

Scott Cline

A

Answer:

Hey Scott thanks for your comment. As you and several others pointed out, he meant that he had been doing electrical work for a long time and "they" had installed the conductors through a concrete hole. We are sorry for inferring that he was doing that type of installation.

Getting the AHJ's thoughts on acceptance prior to doing an installation is a good idea. But allowing individual conductors to be installed through a hole in concrete doesn't seem to comply with 300.3(A) or 300.18(A) besides the concern about water and corrosion.

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