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Friday, October 14, 2016
Question:
I’m often perplexed about what type of wiring to use in a fire rated building.
I’ve used the reasoning that if the building is fire rated but the inside of the building is wood construction, then NM or any type of wiring is acceptable, however, if the internal construction is not combustible then NM is not allowed.
Can you enlighten me on this topic?
R. Richard Verrier
A
Answer:
Hey Richard thanks for your question. It's a little more complicated than just basing the wiring method on the actual type of building construction. For example 334.10(1) allows NM cable to be used in one and two family dwellings without a limitation of what they are constructed of. If a building is constructed of noncombustible materials but would be allowed to be constructed of combustible materials then NM cable is also allowed as stated in 334.10(2) & (3). Informative Annex E has more information related to types of building construction. Review the .10 and .12 sections for the specific wiring method you plan to use to help determine if it is acceptable.