b. As part of a listed assembly
I. General
348.1 Scope. This article covers the use, installation, and construction specifications for flexible metal conduit (FMC) and associated fittings.
348.2 Definition.
Flexible Metal Conduit (FMC). A raceway of circular cross section made of helically wound, formed, interlocked metal strip.
348.6 Listing Requirements. FMC and associated fittings shall be listed.
II. Installation
348.10 Uses Permitted. FMC shall be permitted to be used in exposed and concealed locations.
348.12 Uses Not Permitted. FMC shall not be used in the following:
(1) In wet locations
(2) In hoistways, other than as permitted in
620.21(A)(1)
(3) In storage battery rooms
(4) In any hazardous (classified) location except as
permitted by other articles in this Code
(5) Where exposed to materials having a deteriorating effect on the installed conductors, such as oil or gasoline
(6) Underground or embedded in poured concrete or aggregate
(7) Where subject to physical damage
348.20 Size.
(A) Minimum. FMC less than metric designator 16 (trade size Vi) shall not be used unless permitted in
348.20(A)(1) through (A)(5) for metric designator 12 (trade size %).
(1) For enclosing the leads of motors as permitted in
430.245(B)
(2) In lengths not in excess of 1.8 m (6 ft) for any of the following uses:
a. For utilization equipment
c. For tap connections to luminaires as permitted in
410.117(C)
(3) For manufactured wiring systems as permitted in
604.6(A)
(4) In hoistways as permitted in 620.21(A)(1)
(5) As part of a listed assembly to connect wired luminaire sections as permitted in 410.137(C)
(B) Maximum. FMC larger than metric designator 103 (trade size 4) shall not be used.
FPN: See 300.1(C) for the metric designators and trade sizes. These are for identification purposes only and do not relate to actual dimensions.
348.22 Number of Conductors. The number of conduc- tors shall not exceed that permitted by the percentage fill specified in Table 1, Chapter 9, or as permitted in Table 348.22, or for metric designator 12 (trade size - Vs).
Cables shall be permitted to be installed where such use is not prohibited by the respective cable articles. The number of cables shall not exceed the allowable percentage fill specified in Table 1, Chapter 9.
348.24 Bends — How Made. Bends in conduit shall be made so that the conduit is not damaged and the internal diameter of the conduit is not effectively reduced. Bends shall be permitted to be made manually without auxiliary equipment. The radius of the curve to the centerline of any bend shall not be less than shown in Table 2, Chapter 9 using the column "Other Bends."
348.26 Bends — Number in One Run. There shall not be more than the equivalent of four quarter bends (360 degrees total) between pull points, for example, conduit bodies and boxes.
348.28 Trimming. All cut ends shall be trimmed or otherwise finished to remove rough edges, except where fittings that thread into the convolutions are used.
348.30 Securing and Supporting. FMC shall be securely fastened in place and supported in accordance with
348.30(A) and (B).