What to Know About Burying Underground Electrical Cable

Four Burial Depth Options for Underground Wiring

Decide how much digging you’re prepared to do and how deep your trench will be. This helps determine the type of wiring and the method you’ll use. Underground cable and wire can be installed at different depths, depending on the type of conduit, wire or cable.

Six inches

Install galvanized rigid metal electrical conduit with individual insulated wires six inches deep.

• The wires are pulled through the conduit once the entire conduit run is complete, from end-to-end.
• Wires must be rated for use in a wet location, such as Type THWN-2 (thermoplastic/wet location/nylon jacket).

Twelve inches

Install GFCI-protected direct-buried Type UF cable 12 inches deep.

• The GFCI protection is a trade-off that provides enhanced electrical safety while reducing the need for a deeper trench.

Eighteen inches

Install PVC conduit with individual insulated wires 18 inches deep.

• The wires are pulled through the conduit once the entire conduit run is complete, from end-to-end.
• Wires must be rated for use in a wet location, such as Type THWN-2 (thermoplastic/wet location/nylon jacket).

Twenty-four inches

Install Type UF cable for the entire run 24 inches deep.

• This is another trade-off between depth and physical protection.
• Because the direct-buried cable is alone in the bottom of the trench without conduit or GFCI protection, it must be installed deeper in the ground.

Read on for the specifics about each option.