page_title: Electrical conduit
section_title: Non-metal
hierarchical_section_title: Electrical conduit / Types / Non-metal
caption_attribution_description: Grey Schedule 40 PVC plastic tubing for use as a conduit for electric wires
context_page_description: An electrical conduit is a tube used to protect and route electrical wiring in a building or structure. Electrical conduit may be made of metal, plastic, fiber, or fired clay. Most conduit is rigid, but flexible conduit is used for some purposes.
  Conduit is generally installed by electricians at the site of installation of electrical equipment. Its use, form, and installation details are often specified by wiring regulations, such as the US National Electrical Code and other building codes.
context_section_description: PVC conduit has long been considered the lightest in weight compared to steel conduit materials, and usually lower in cost than other forms of conduit. In North American electrical practice, it is available in three different wall thicknesses, with the thin-wall variety only suitable for embedded use in concrete, and heavier grades suitable for direct burial and exposed work.  Most of the various fittings made for metal conduit are also available in PVC form. The plastic material resists moisture and many corrosive substances, but since the tubing is non-conductive an extra bonding (grounding) conductor must be pulled into each conduit. PVC conduit may be heated and bent in the field, by using special heating tools designed for the purpose.
  Joints to fittings are made with slip-on solvent-welded connections, which set up rapidly after assembly and attain full strength in about one day. Since slip-fit sections do not need to be rotated during assembly, the special union fittings used with threaded conduit (such as Ericson) are not required. Since PVC conduit has a higher coefficient of thermal expansion than other types, it must be mounted to allow for expansion and contraction of each run.  Care should be taken when installing PVC underground in multiple or parallel run configurations due to mutual heating effect of densely packed cables, because the conduit will deform when heated.
  Reinforced  thermosetting resin conduit (RTRC) or fiberglass conduit  is light in weight compared to metallic conduits, which contributes to lower labor costs. It is sometimes referred to as FRE which stands for "fiberglass reinforced epoxy", however this term is a legally registered trademark of FRE Composites. It may also provide lower material cost. RTRC conduit can be used in a variety of indoor and outdoor applications. Fiberglass conduit is available in multiple wall thicknesses to suit various applications and has a support distance very similar to steel. High temperature, low smoke, no flame, classified area (Class I Division 2), and zero halogen versions are also manufactured for specialty applications such as subway tunnels and stations and in the US can meet NFPA 130 requirements. Like other non-metallic conduits, a bonding conductor may be required for grounding. Joints are epoxy-glued, which requires some installation labor and time for joints to set. RTRC conduit may not be bent in the field and appropriate fittings must be used to change directions, nor is RTRC conduit approved to support luminaires.
  Rigid nonmetallic conduit (RNC) is a non-metallic unthreaded smooth-walled tubing.
  Electrical nonmetallic tubing (ENT) is a thin-walled corrugated tubing that is moisture-resistant and flame retardant. It is pliable such that it can be bent by hand, and is often flexible although the fittings are not. It is not threaded due to its corrugated shape, although some fittings might be.
caption: Plastic tubing for use as electrical conduit.
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