UL 651A

Schedule 40 and 80 High Density Polyethylene (HDPE) Conduit

1.1 These requirements cover straight conduit and coilable, smooth-wall, continuous length conduit with a circular cross section:

a)    Extruded straight rigid Schedule 40 high density PE (polyethylene) electrical conduit and the following fittings for use with this conduit type:

1)    Elbows and

2)    Rigid high density PE couplings.

b)    Schedule 40, Schedule 80, EPEC-A, and EPEC-B coilable, smooth-wall continuous length high density PE electrical conduit.

1.2 The conduit and fittings mentioned in 1.1 are intended for use at 50°C (122°F) and lower ambient temperatures. Extruded straight rigid Schedule 40 conduit and fittings, where directly buried or encased in concrete in trenches outside of buildings, may be used with 90°C (194°F) wiring.

1.3 The conduit and fittings covered in these requirements are intended for use as rigid nonmetallic raceway for wires and cables in accordance with the National Electrical Code, NFPA 70.

1.4 Extruded straight rigid Schedule 40, Schedule 40, Schedule 80, EPEC-A, and EPEC-B coilable conduit is for aboveground use where encased in not less than 2 inches (50 mm) of concrete and for underground use by direct burial or encasement in concrete.


  • Edition Number: 5
  • Edition Date: 10/26/2011
  • Price Code: B
  • Type: ulstd
  • ANSI Approved: 06/24/2016
  • DOD Approved: 11/30/1984