National Electrical Installation Standards

Standards as High as Your Own

Wednesday, April 1, 2020


Thank you for taking my question. I follow this daily and have for many years. I also am an a electrician and electrical instructor. My question is if I were to rewire an existing apartment on the 19th floor in a type one construction. The floors and above the ceilings are concrete and all metal studs. The existing wiring method is type NMC. Building is 60 yrs old. Every floor has 4 apartments. Customer wants new lighting and receptacle outlets added. I believe NMC is allowed per NEC because of the type of construction. Please give me your thoughts. I know the AHJ has final say.

Randy Adams



Hi Randy, thanks for the question. Based on the information provided, we will provide a response. Your last sentence in this inquiry is an important one, which acknowledges the AHJ in the decision process, especially with existing and remodeling installations. At face value, without know all of the parameters, the NMC would be acceptable is it meets the requirements in Section 334.10(B)(3) of the Code.  On an older installation like this it is best to meet with the AHJ and get their input on hoe they will apply the NEC in this specific installation. 

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