RIGID NONMETALLIC CONDUIT

347-1. Description. This article shall apply to a type of conduit and fittings of suitable nonmetallic material that is resistant to moisture and chemical atmospheres. For use aboveground, it shall also be flameretardant, resistant to impact and crushing, resistant to distortion from heat under conditions likely to be encountered in service, and resistant to low temperature and sunlight effects. For use underground, the material shall be acceptably resistant to moisture and corrosive agents and shall be of sufficient strength to withstand abuse, such as by impact and crushing, in handling and during installation. Conduits listed for the purpose shall be permitted to be installed underground in continuous lengths from a reel. Where intended for direct burial, without encasement in concrete, the material shall also be capable of withstanding continued loading that is likely to be encountered after installation. 347-2. Uses Permitted. The use of listed rigid nonmetallic conduit and fittings shall be permitted under the following conditions: (FPN): Extreme cold may cause some nonmetallic conduits to become brittle and therefore more suceptible to damage from physical contact. (a) Concealed. In walls, floors, and ceilings. (b) Corrosive Influences. In locations subject to severe corrosive influences as covered in Section 300-6 and where subject to chemicals for which the materials are specifically approved. (c) Cinders. In cinder fill. (d) Wet Locations. In portions of dairies, laundries, canneries, or other wet locations and in locations where walls are frequently washed, the entire conduit system including boxes and fittings used therewith shall be so installed and equipped as to prevent water from entering the conduit. All supports, bolts, straps, screws, etc., shall be of corrosion-resistant materials or be protected against corrosion by approved corrosion-resistant materials. (e) Dry and Damp Locations. In dry and damp locations not prohibited by Section 347-3. (f) Exposed. For exposed work where not subject to physical damage if identified for such use. (g) Underground Installations. For underground installations, see Sections 300-5 and 710-4(b). 347-3. Uses Not Permitted. Rigid nonmetallic conduit shall not be used: (a) Hazardous (Classified) Locations. In hazardous (classified) locations, except as covered in Sections 503-3(a), 504-20, 514-8, and 515-5; and in Class I, Division 2 locations as permitted in the exception to Section 501-4(b). (b) Support of Fixtures. For the support of fixtures or other equipment. Exception: Rigid nonmetallic conduit shall be permitted to support nonmetallic conduit bodies no larger than the largest trade size of an entering raceway. The conduit bodies shall not contain devices or support fixtures.