Question

You are installing 120VAC power cables underground in rigid galvanized steel conduit beneath a residential driveway. How deep must the conduit be buried?

Answer 1

If your cables are operating a 120-volt circuit, protected by a circuit breaker rated at 20 amps or less, and have a ground fault circuit interrupter to protect the underground segment of the cable, you may reduce the burial depth of your cables. The generally applicable depth is 12 inches, or you can reduce it to 6 inches if you protect the cables with 2 inches of concrete. Under a driveway, you may only need 12 inches of burial depth. Conduits are required for installation in 2 inches of solid rock with concrete. These depth reductions apply no matter which burial method is chosen.