Underground Electrical Conduit Depth

Emt and imc conduits should not be used for underground electrical wiring installations.

Underground electrical conduit depth.

At 18 inches you can use thwn 2 conductors inside a continuous length of pvc conduit which protects the wire all the way through the trench to the house. Where solid rock prevents compliance with the cover depths specified in this table the wiring shall be installed in metal or non metallic raceway permitted for direct burial. Cable in any conduit including pvc that is buried at this depth is not in danger of being severed or disturbed by normal digging. You may also run them at a depth of 4 inches under a 4 inch concrete slab.

Conduits for underground electrical wiring pvc and rigid conduits are typically used when installing underground electrical wiring. The depth for underground conduit is typically 18 inches depending on the specific installation and project type. Buried wiring runs that transition from underground to above ground must be protected in conduit from the required cover depth or 18 inches whichever is less to its termination point above ground or at least 8 feet above grade. In general bury metal conduits at least 6 inches below the soil surface.

Low voltage wiring carrying no more than 30 volts must be buried at least 6 inches deep. At 24 inches you can bury underground feeder cable using pvc conduit to 18 inches below ground only where the wire comes up. Backfill surrounding conduit or cables must be smooth granular material without rocks. The raceways shall be covered by a minimum of 50 mm 2 in of concrete extending down to rock.