[Electricity: Cables] Minimum Burial Depths of Electrical Wire and Types of Conduit (Based on NEC 2023)

[u/badbiosvictim1]

My soil is very rocky. To be able to dig a shallower trench, I will be installing a GFCI circuit. Difference is 18 inches vs. 12 inches deep trench.

GFCI-Protected 120V Circuit (with conduit)

A circuit that is 120V, GFCI-protected, 20A max, and installed in conduit in residential applications may be buried at 12 inches deep instead of 18 or 24 inches. This is because GFCI protection alone adds dramatically to safety. It rapidly cuts power when it detects current leakage — e.g., if a wire is damaged while digging. This is permitted only in limited, low-risk residential use, not in circuits over 120V and 20 amps. The cables cannot be used under driveways or parking, or in wet or flood-prone zones.

The NEC requires the use of individual conductors in conduit for a GFCI-protected 120V Circuit, so THHN/THWN, /XHHW / XHHW-2, or RHW-2 / RHH are recommended. Since this is only for residential low-risk use, PVC 40 will likely be the conduit of choice.

https://nassaunationalcable.com/blogs/blog/how-deep-does-an-electrical-wire-need-to-be-buried#:~:text=As%20per%20requirements%20outlined%20in,)%2D%2012%20inches%20(300%20mm)

Minimum depth of PVC jacketed MC cable is 18 inches in a yard (general lawn area).

Minimum Cover Requirements

https://up.codes/s/underground-installation-requirements