ELECTRICAL METALIC TUBING
(FJMX)
General
This category covers electrical metallic tubing (EMT), including lengths of straight tubing and elbows, with or without integral couplings or other integral fittings, manufactured in trade sizes 1/2 to 4 (metric designators 16 to 103) inclusive. EMT is for installation of conductors in accordance with Article 358 of ANSI/NFPA 70, ‘‘National Electrical Code’’ (NEC). This tubing is intended for installation and use in accordance with the following information. Galvanized or stainless steel EMT installed in concrete on grade or above generally requires no supplementary corrosion protection. Galvanized steel EMT in concrete slab below grade level may require supplementary corrosion protection. In general, galvanized steel EMT in contact with soil requires supplementary corrosion protection. Where galvanized steel EMT without supplementary corrosion protection extends directly from concrete encasement to soil burial, severe corrosive effects are likely to occur on the metal in contact with the soil. Galvanized or stainless steel EMT that is provided with a metallic or nonmetallic coating, or a combination of both, has been investigated for resistance to atmospheric corrosion. Nonmetallic outer coatings that are part of the required resistance to corrosion have been additionally investigated for resistance to the effects of sunlight. Nonmetallic outer coatings of greater than 0.010-in. thickness are investigated with respect to flame propagation detrimental effects to any underlying corrosion protection, the fit of fittings, and electrical continuity of the connection of tubing to fittings. Galvanized steel EMT with nonmetallic coatings has not been investigated for use in ducts, plenums, or other environmental air spaces in accordance with the NEC. Galvanized steel EMT with or without a nonmetallic coating has not been investigated for severely corrosive conditions. Aluminum EMT used in concrete or in contact with soil requires supplementary corrosion protection. PRODUCT IDENTITY One of the following product identities appears on the product: Electrical Metallic Tubing EMT