National Electrical Installation Standards

Standards as High as Your Own

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Thursday, February 14, 2019

Question:

Does 310.15(a)(2) apply to a sheet metal trough pertaining to the 30 current carrying conductor rule?

Steve Potter

A

Answer:

Hey Steve thanks for your question. If I understand your question correctly then yes. If part of a run includes conductors in a wireway that that portion must be considered if it exceeds the conditions of the exception for 310.15(A)(2). You are probably aware but adjustment factors of 310.15(B)(3)(a) only need to be applied if the number of current carrying conductors in a metal wireway exceeds 30 as stated in 376.22(B).

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