These requirements cover nonmetallic-sheathed cables containing 2 – 4 thermoplastic-insulated circuit conductors, with a grounding conductor, in the constructions indicated in Table 1. These cables are intended for use in accordance with Article 334 and other applicable parts of the National Electrical Code, NFPA 70. Type NMC cable is for use in dry, moist, damp, and corrosive locations, and Type NM cable is for use in normally dry locations. Both types carry the suffix letter ²-B² to designate the use of conductors with 90°C insulation.
A cable to which the designation "ST1" (signifying "limited smoke") is applied as a type-letter suffix complies with the test criteria for smoke release and for cable damage height stated in the Standard for Vertical-Tray Fire-Propagation and Smoke-Release Test for Electrical and Optical-Fiber Cables, UL 1685.