FLEXIBLE METAL CONDUIT

70-255 350-2. Uses Not Permitted. Flexible metal conduit shall not be used (1) in wet locations unless conductors are of lead-covered type or of other types approved for the specific conditions and the installation is such that water is not likely to enter other raceways or enclosures to which the conduit is connected; (2) in hoistways, other than provided in Section 620-21; (3) in storage-battery rooms; (4) in any hazardous (classified) location other than permitted in Sections 501-4(b) and 504-20; (5) where rubber-covered conductors are exposed to oil, gasoline, or other materials having a deteriorating effect on rubber; (6) underground or embedded in poured concrete or aggregate; or (7) where subject to physical damage. 350-3. Minimum Size. Flexible metal conduit less than 1/2-inch electrical trade size shall not be used. Exception No. 1: For enclosing the leads of motors as permitted in Section 430-145(b). Exception No. 2: Flexible metal conduit of ³/₈-inch nominal trade size shall be permitted in lengths not in excess of 6 feet (1.83 m) as a part of a listed assembly, or for tap connections to lighting fixtures as required in Section 410-67(c), or for utilization equipment. Exception No. 3: Flexible metal conduit of ³/₈-inch nominal trade size shall be permitted for manufactured wiring systems as permitted in Section 604-6(a). Exception No. 4: As permitted in Section 620-21, Exception No. 5. Exception No. 5: Flexible metal conduit of ³/₈-inch nominal trade size shall be permitted as part of a listed assembly to connect wired fixture sections as permitted in Section 410-77(c). Table 350-3. Maximum Number of Insulated Conductors in 3/8-Inch Flexible Metal Conduit* Col. A = With fitting inside conduit. Col. B = With fitting outside conduit. Types Types TF, Types Types FEP, Size RFH-2, XHHW, AF, TFN, THHN, FEPB, PF, AWG SF-2 TW THWN PGF A B A B A B A B 18 3 3 7 4 8 5 8 16 2 2 4 3 7 4 8 14 4 3 7 3 7 12 3 4 4 10 2 3 * In addition, one uninsulated equipment grounding conductor of the same size shall be permitted. 350-4. Supports. Flexible metal conduit shall be secured by an approved means at intervals not exceeding 4½ feet (1.37 m) and within 12 inches (305 mm) on each side of every outlet box, junction box, cabinet, or fitting. Exception No. 1: Where flexible metal conduit is fished. 70-256 NATIONAL ELECTRICAL CODE Exception No. 2: Lengths not exceeding 3 feet (914 mm) at terminals where flexibility is necessary. Exception No. 3: Lengths not exceeding 6 feet (1.83 m) from a fixture terminal connection for tap connections to lighting fixtures as required in