Steel Rigid Steel Conduit (RSC) has the thickest-wall of the steel raceways. It is available with either a straight-tapped or integral coupling. Galvanized Steel RMC may have a primary coating of zinc on the exterior and interior of the conduit; a combination of zinc and nonmetallic coating are also permitted. Supplementary coatings can be applied for additional corrosion protection.
RMC is available in trade sizes 1/2 through 6, and 10′ and 20′ lengths. RMC is threaded on both ends, with a coupling applied to one and a thread protector on the other.
RMC is covered under Article 344 of the NEC, UL 6 and ANSI C80.1.