Underground Burial Depths (Table 300.5) and Physical Protection (300.4)

Buried wiring has to be deep enough that a shovel or a stake won't hit it, and wiring inside walls has to be far enough from the surface that a drywall screw won't pierce it. Two rules cover this.

1. Minimum burial depth — Table 300.5

The required cover (depth) depends on the wiring method and the location/circuit type. The most-tested general rows (0–1000 V):

Wiring method	Minimum cover
Direct-buried cable/conductors (e.g., UF)	24 in
RMC or IMC (rigid/intermediate metal conduit)	6 in
Rigid PVC / nonmetallic raceway	18 in
Residential 120 V, ≤20 A, GFCI-protected branch circuit	12 in

Memory aid: the tougher the method, the shallower it's allowed — bare direct burial needs the most cover (24 in); rigid steel conduit needs the least (6 in).