These requirements cover steel electrical intermediate metal conduit (IMC)@ nipples@ elbows@ and couplings. This conduit is provided in trade sizes 1/2 ?C 4 (16 ?C 103)@ for use as a metal raceway for the installation of wires and cables in accordance with the National Electrical Code (NEC)@ NFPA 70. The values in parentheses are metric designators of conduit.Steel intermediate metal conduit is provided with an exterior coating of zinc or a zinc-based@ nonmetallic@ or other alternate corrosion-resistant material and an interior coating of an organic or zinc material. Each of these exterior and interior coatings provides an acceptable level of corrosion resistance in normally corrosive environments. It is the user??s responsibility to determine the appropriate product for the application.