Rigid Metal Conduit (RMC)

Steel RMC 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.

Electrical Code Compliance

The National Electrical Code® Article 344 covers rigid metal conduit, which includes galvanized and stainless steel, aluminum and red brass. Steel RMC is permitted in all atmospheric conditions and occupancies. The listing label for this product will be identified with one of the following: “Electrical Rigid Metal Conduit” or “ERMC-S”.

RMC Trade Sizes

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 color-coded thread protector on the other. The industry-established color-coded thread protectors aid in product and trade size recognition. Thread protectors for trade sizes 1, 2, 3, 4, 5 and 6 are color coded blue; trade sizes 1/2, 1 1/2, 2 1/2 and 3 1/2 are black; and trade sizes 3/4 and 1 1/4 are red.

Steel RMC Corrosion Protection

A variety of coating options are available to protect galvanized steel RMC against corrosion. ERMC-S is provided with zinc, zinc-based, nonmetallic, or other alternate corrosion-resistant exterior coating and an organic or zinc interior coating.

RMC Weights and Dimensions

Trade Size DesignatorNominal Wt. per 100 Ft. (30.5m)Nominal Outside DiameterNominal Wall ThicknessQuantity in Primary BundleMaster Bundles
QuantityApprox. Wt.Volume
U.S.Metriclb.kgin.mmin.mmft.mft.mmlb.kgcu ft.cu m
1 1/43521898.91.66042.20.1333.40--900274.51962889.823.30.66
1 1/241263119.31.90048.30.1383.50--800244.02104954.227.80.79
2 1/263559253.52.87573.00.1934.90--370112.92068937.929.20.83
3 1/291880399.14.000101.60.2155.50--25076.32200997.734.70.98