National Electrical Installation Standards

Standards as High as Your Own

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Wednesday, July 11, 2018

Question:

We have a new construction in Boston that uses fire rated construction on the parking level and then builds from there with conventional lumber 3 to 5 floors. My question is regarding type NM cable, can NM cable be run through the parking area and then up to the units above? My inclination says no, type MC cable should be used. Any thoughts?

Stephen McCarthy

A

Answer:

Hey Stephen thanks for your question. NM cable is allowed to be installed in structures that are allowed to be of Types III, IV, or V construction (not fire resistant). If the parking area is required to be fire resistant (which is likely why it is of that type) then NM is not permitted. See NEC Annex E and NFPA 220 for more information on building construction types.

Yes, MC cable, or any other suitable wiring method can be used, or in the parking area the NM cable can be installed in raceways as stated in 334.10(5).

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