How to Mount & Hard Wire an Under-Cabinet Fixture

Turn off the breaker supplying electricity to the wall outlets between the countertop and the cabinet. Insert both needles from a two-wire electrical tester into each outlet along the wall as if you were inserting a plug into the outlet. The tester will fail to light if the correct breaker is in the “Off” position.

Remove the wall plate from the outlet to expose the outlet and the wiring. Take out the screws located at both the top and bottom of the outlet.

Pull the outlet from the electrical box in the wall. Loosen the screws holding the black wire, white wire, and bare copper or green ground wire to the outlet. Remove the wires from beneath the screws. Depending on where the outlet is located on the electrical circuit, there could be a black wire attached to both sides of the outlet, a white wire attached the same way and possibly an extra ground wire attached to the green grounding screw.

Use a 1/2-inch wood drill bit and power drill to create a 1/2-inch hole through the lip on the underside of the cabinet, directly above the open electrical box.

Feed a stiff piece of wire through the electrical box in the wall and up to the hole you drilled. Shine a flashlight into the hole to watch for the wire. Grab the wire through the hole with needle-nose pliers and pull it out.

Cut a length of 12-2 nonmetallic electrical cable to equal the distance between the electrical box in the wall and the hole beneath the cabinet plus 16 inches. Attach one end of the cable to the stiff wire with electrical tape. Pull the other end of the stiff wire from the electrical box to insert the wire behind the wall. Leave 8 inches of cable protruding from the hole beneath the cabinet and out the electrical box.

Use a cable ripper to remove the exterior cover from both ends of the 12-2 electrical cable. This exposes the interior black, white and bare copper wires inside the cable. Use wire strippers to remove 3/4 inch of the exterior insulation from both the black and the white wires at both the electrical box end of the cable and the hole in the wall beneath the cabinet.

Take the cover off your under-cabinet fixture. This could involve removing the screws access the inside of the fixture and the wiring, or it could call for popping the light cover from the channels holding it in place and sliding the cover from over the wiring.

Position a screwdriver over the circular knockout on the fixture. Strike the handle of the screwdriver with a small hammer to push the knockout from the fixture.

Insert the threads of a two-screw wire connector into the knockout. Secure the connector to the fixture by twisting the locknut, provided with the connector, onto the connector threads. Thread the wires from the hole in the wall through the connector in the fixture.

Secure the under-cabinet fixture beneath the cabinet with 1/2-inch wood screws. The number of screws you use depends on the size of your fixture and the number of mounting holes cut into the fixture.

Attach the white wire from inside the cable to the white wire from the under-cabinet fixture with a twist-on wire connector. Connect the black wire from inside the cable to the black fixture wire and the bare copper wire from the cable to the green fixture wire with two more connectors.

Replace the cover over the wiring and the light lens on the fixture, if applicable. Tighten the two screws attached to the two-screw wire connector on the exterior of the fixture to secure the wire to the fixture.

Cut an 8-inch piece of 12-gauge black electrical wire, white electrical wire and green electrical wire. Strip 3/4 inch of colored wire insulation from both ends of each 8-inch piece of wire.

Connect one of the black wires, if there are two, and the black wire from inside the new electrical cable to the 8-inch piece of black wire with a twist-on orange wire connector. Repeat this same connection for the white wires and for the 8-inch green wire to the bare copper ground wire.

Wrap the other end of the 8-inch black wire around the top screw on the electrical outlet you previously removed. Wrap the short white wire around the bottom screw and the short green wire around the green screws.

Tighten the screws on the outlet to hole the wires in place. Replace the wires on the opposite side of the outlet if there were additional wires on the outlet. Attach the black to the top, white to the bottom and bare copper to the green screw.

Push the wires into the electrical box. Attach the wall outlet to the box with the screws you removed previously. Replace the outlet cover. Turn on the circuit breaker to supply the electricity to the under-cabinet fixture.