Understanding NEC Article 334: Nonmetallic-Sheathed Cable (Types NM and NMC) Introduction NEC Article 334 establishes the requirements for the use, construction, and installation of nonmetallic-sheathed cable, commonly referred to as Types NM (Nonmetallic) and NMC (Nonmetallic Corrosion-Resistant). First introduced in the 1928 NEC, these cable types were developed as a safer and more efficient alternative […]