In this video, electrician Scott Caron shows a homeowner how to bring power to a detached garage.
1. Call the local utility company and have them check for buried pipes or wires.
2. Rent a gas-powered trenching machine and dig a trench at least 12 inches deep from the house to the garage.
3. Bore a 1½-inch-diameter hole through the house wall and into the basement with a drill and hole saw. Position the hole directly above the end of the trench.
4. Cut a length of ¾-inch-diameter plastic conduit to extend from the bottom of the trench up to the hole in the house wall.
5. If necessary, use a propane-powered heat gun to bend the conduit to conform to the foundation.
6. Attach a plastic conduit outlet body to the end of the conduit.
7. Push a length of UF (underground feed) electrical cable into the conduit, then feed the end of the cable through the hole in the house wall.
8. From inside the basement, pull the cable all the way to the main electrical panel. Secure the cable to the overhead joists with cable staples.
9. Go outside and lay the cable into the trench, running it all the way to the garage.
10. At the garage, repeat Steps 3 through 7 to install the plastic conduit and cable.
11. After feeding the cable into the garage, screw the conduit outlet body to the exterior wall of the garage. Screw the other conduit body to the house wall.
12. Apply exterior-grade acrylic-latex caulk around the conduit outlet body to seal out water.
13. Cover the cable with about 2 inches of sand, then lay caution tape on top of the sand along the entire trench.
14. Backfill the trench with the excavated soil.
15. Have a licensed electrician make the final wire connections in the garage and at the main electrical panel.