Article 355 of the National Electrical Code (NEC) details the scope of accepted use, installation, and construction for fiberglass conduit, also known as reinforced thermosetting resin conduit (RTRC), and it’s associated fittings.
The code defines fiberglass conduit as “a rigid nonmetallic raceway of circular cross-section, with integral or associated couplings, connectors, and fittings for the installation of electrical conductors and cables.”
The following uses are permitted for fiberglass conduit trade size 1/2 through trade size 6:
- When concealed in walls, floors and ceilings
- When subject to corrosive environments covered in Section 300.6
- When subject to approved chemicals
- In cinder fill
- In wet conditions including dairies, laundries, canneries, or where walls are frequently washed, when the conduit system is equipped to prevent water from entering the conduit.
- In dry and damp locations not prohibited by Section 355.12
- In exposed areas
- In underground installations