UL STANDARD FOR SAFETY Liquid-Tight Flexible Metal Conduit
|Publication Date:||17 January 2013|
These requirements cover the 3/8 (12), 1/2 (16), 3/4 (21), 1 (27), 1-1/4 (35), 1-1/2 (41), 2 (53), 2-1/2 (63), 3 (78), 3-1/2 (91), and 4 (103) trade sizes (metric designators) of liquid-tight flexible steel, aluminum, brass, bronze, copper, and stainless steel conduit. The conduit covered is intended for installation in accordance with the National Electrical Code (NFPA 70) as raceway for wires and cables.
This conduit is for applications in which flexibility of the conduit is necessary during installation, operation, or maintenance and the contained conductors need protection from vapors, liquids or solids.
This conduit is circular in cross section, having an outer liquid-tight, nonmetallic, sunlight-resistant jacket over an inner flexible metal core, and is for use in wet, dry, or oily locations in which the conduit is exposed but is not subject to physical damage. Conduit that is not marked with a temperature designation or is marked "60 C" is for use at temperatures not in excess of 60°C (140°F). Conduit that is for use in dry or oily locations at a temperature higher than 60°C (140°F) is marked "____C dry, 60 C wet, 70 C oil res" or "____C dry, 60 C wet, 70 C oil resistant" with "80 C" or "105 C" inserted as the dry-locations temperature.
Conduit that is marked "80 C dry, 60 C wet, 60 C oil res" or "80 C dry, 60 C wet, 60 C oil resistant" is for use at 80°C (176°F) and lower temperatures in air, and 60 °C (140°F) and lower temperatures where exposed to water, oil or coolants - that is, to cutting oils and the like in machine-tool and other industrial applications.
Conduit marked in accordance with 24.4(g) is limited to use in oil free environments.
Fittings for conduit are covered in the Standard for Conduit, Tubing, and Cable Fittings, UL 514B.
These requirements do not cover liquid-tight flexible nonmetallic conduit. Flexible nonmetallic conduit is covered in the Standard for Liquid-Tight Flexible Nonmetallic Conduit, UL 1660, and the fittings for this conduit are covered in the Standard for Conduit, Tubing, and Cable Fittings, UL 514B.
These requirements do not cover flexible metallic tubing.
These requirements do not cover electrical nonmetallic tubing (ENT).