Expansion fittings must be installed above grade when direct buried PVC conduit emerges from the ground and compensation is needed for earth settling or movement, including frost heave.
Code Change Summary: New requirements for expansion fittings where earth movement is an issue.
In the 2023 NEC ® , Section 352.44(B) was added which requires expansion fittings to be installed above grade when direct buried PVC conduit emerges from the ground and compensation is needed for earth settling or movement, including frost heave.
Before this new code section was added, Article 352 only required expansion fittings in PVC conduits (to compensate for thermal expansion and contraction) where the length change, in accordance with Table 352.44, was expected to be 1⁄4 inch or greater in a straight run between securely mounted items such as boxes, cabinets, elbows, or other conduit terminations. Underground PVC conduits emerging from grade were not mentioned.
Other general requirements on wiring methods and earth movement can be found in existing NEC ® Section 300.5(J) which addresses direct-buried conductors, raceways, or cables that are subject to movement by settlement or frost. This section requires direct-buried conductors, raceways, or cables to be arranged so as to prevent damage to the enclosed conductors or to equipment connected to the raceways.
The informational note in Section 300.5(J) recognizes expansion fittings in raceway risers connected to fixed equipment subject to settlement or frost heaves.
Below is a preview of the NEC ® . See the actual NEC ® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2023 NEC ® edition of NFPA 70.
2020 Code Language:
This code section did not exist.
2023 Code Language:
N 352.44(B) Earth Movement. Expansion fittings for underground runs of direct buried PVC conduit emerging from the ground shall be provided above grade when required to compensate for earth settling or movement, including frost heave.
Informational Note: See 300.5(J).
Below is a Real Question from our Electrical Continuing Education Courses for Electrical License Renewal:
Based on the 2023 NEC, which of the following is true of direct buried PVC conduits emerging from the ground?
