UL 1 Standard for Flexible Metal Conduit
These requirements cover flexible aluminum and steel conduit designed for use as n wires and cables in accordance with the National Electrical Code, NFPA 70.
Strip Material Steel
The strip material used in flexible steel conduit shall be carbon steel, shall have < of at least 34,000 lbf/in2 (234.5 MPa) and shall be of uniform width and thickness througf of the strip shall be free from scale and rust before application of the protective zinc co; Section 10.
Compliance of conduit with the surface-cleanliness requirement in 4.1.1 is to b visual inspection.
The strip from which flexible aluminum conduit is made shall have
A tensile strength of at least 34.000 lbf/in2 (234.5 MPa) and
A copper content of 0.40 percent or less.
The strip shall be of uniform width and thickness throughout.
Thickness of Strip
The thickness of the metal strip used for flexible metal conduit shall not be less Table 5.1 for standard wall flexible metal conduit (FMC).
Exception: The thickness of the metal strip may be less than indicated in Table 5.1 complies with the requirements specified for reduced-wall flexible metal conduit (RWFMC
Compliance of conduit with the requirement in 8.1 is to be determined by visual ex interior surfaces. A specimen of conduit approximately 1 ft (300 mm) in length is to be insp through it (first from one end then from the other) at an artificial light
Finished flexible steel and aluminum conduit in trade sizes 3/8.
A specimen of the zinc-coated tested before terming shall not show a deposit of copper on any surface, including edges, after two 60-second immersion copper sulphate.
A specimen of finished flexible steel and aluminum conduit shall be bent around a< circular) surface having a radius as indicated in Table 12.1 without opening at any point.
Deformation of the less than 50 percent as determined by measuring the overall diameler of the conduit comparing it to the original value.