How deep does UF cable need to be buried?

NEC 2023 Table 300.5 requires 24 inches of cover for direct buried UF cable in most locations. A 120 volt, 20 amp or smaller GFCI protected residential branch circuit can be reduced to 12 inches.

Does a detached garage need its own ground rods?

Yes. NEC 250.32(A) requires a grounding electrode at a detached structure supplied by a feeder, and the feeder must carry an equipment grounding conductor per 250.32(B).

Running UF Cable From a Detached Garage to Your House Panel

This one came from a real question in the Ask BONBON app: how should UF cable be run from a detached garage into the panel at the house? The answer lives in NEC 2023 Articles 300, 340, and 250, and the details matter because inspectors check every one of them.

First, burial depth. Table 300.5 calls for 24 inches of cover for direct buried UF cable under most conditions. If the run is a single 120 volt branch circuit rated 20 amps or less and it has GFCI protection at the source, the table allows a reduced 12 inch depth. Under a driveway you are back to 24 inches, and under a building UF must be in raceway.

Protect the cable where it leaves the ground

NEC 300.5(D) requires physical protection where the cable emerges. Sleeve the cable in rigid metal conduit, IMC, or Schedule 80 PVC from 18 inches below grade up to at least 8 feet above grade or to the point of entry. UF is sunlight resistant when marked, but the emerging section still needs that mechanical protection. Use a bushing or fitting at the top of the sleeve so the sheath is not damaged on the edge.

Grounding at two structures

Because this run connects two separate structures, NEC 250.32 applies. Run four wires on a multiwire feeder or three wires on a 120 volt circuit: the ungrounded conductors, the neutral, and an equipment grounding conductor sized per 250.122. Do not bond the neutral and ground together at the second structure. The panel at the structure that receives the feeder also needs its own grounding electrode system per 250.32(A), which usually means two ground rods unless one rod tests at 25 ohms or less per 250.53(A)(2).

Entering the panel

Where the UF enters the house, use a listed cable connector at the enclosure and keep the sheath intact until inside the box per 312.5(C). Inside a basement or crawl space, follow the securing and support rules of 340.10 and 334.30, meaning staples or straps within 12 inches of the box and every 4.5 feet along the run.

One more field note: if the garage has more than one circuit, you need a disconnecting means at the garage per 225.31 and 225.32, and a small subpanel there usually makes the whole job cleaner than stretching a single circuit.

Want the exact table values for your wire size and load? Ask BONBON cites the section and table so you can show the inspector where the answer came from.