Install Undercabinet Lighting

Each undercabinet lighting kit comes with a power cord equipped with a rotary switch for turning the light on and off. You’ll likely find using that switch awkward.

Instead, to illuminate your countertop at the flick of a switch, install a combination switch/receptacle in place of the electrical outlet where you intend to plug in your undercabinet light. You can do this installation easily if you have some experience with electrical wiring; if not, hire a qualified electrician to switch out the outlet for a combo switch/receptacle.

If the on-cord switch is fine with you, skip the next four steps.

Plug a lamp into the top outlet of the receptacle you plan to replace. Head to the basement or wherever the breaker box is, switch off the circuit breaker serving that receptacle and then fasten a sticky note to the breaker warning “Do not switch on!”

Head back to the kitchen and check that the lamp has turned off. Plug the lamp into the receptacle’s bottom outlet to confirm that it, too, has no electricity flowing to it. If the lamp turns on, you have a switched receptacle or one served by two circuits. Try another receptacle.

Remove the cover plate from the receptacle and then unfasten the two screws that hold the receptacle to the box.

Gently pull the receptacle out, loosen the terminal and ground screws, and detach the wires. If you find the wires pushed into the back of the receptacle body instead of attached to terminal screws, nip the wires off with cutting pliers.

Always check the manufacturer’s instructions for wiring the combination switch/receptacle — devices vary.

• If there is only one cable in the box, simply attach the bare copper or green-insulated wire hanging out of the wall to the green ground terminal screw of the combo switch receptacle. Then attach the white wire to the chromium screw and the black wire to the brass screw.
• If your combo switch receptacle does not have a tab, run a small jumper cable between the black screws on one side of the device.

Attach each wire so the wire loop points clockwise to screw head, so the wire winds tightly around the screw shank.

If you find two cables going into the box, one is the feeder line bringing power from the breaker box and the other carries power to other receptacles down the line. To avoid interrupting this flow, use 6-inch pieces of electrical wire called "pigtails," as shown. Strip 3/4 inch of insulation off each wire, twist the wires together with lineman’s pliers and fasten the twisted wires on a wire nut. Attach the copper or green-insulated pigtail to the green ground screw, the white pigtail to the chromium screw, and the black pigtail to the brass screw.

Wrap electrical tape over the terminal screws to protect the connections.

Plug in a single puck light, turn it on and hold it under the cabinet to evaluate the effect. You want to place the fixture close to the front of your cabinet, but you don't want it casting an obnoxious glare across the room. When you find a happy medium, measure the light's distance from both the wall and the front of the cabinet. Mark these spots.

Hook up a second puck light to decide how far apart you want the fixtures — 12 to 16 inches works well in most situations. Locate pucks at least 4 inches from the end of each cabinet; mounting a light right at the end of a cabinet looks odd. Measure and mark the spots for each puck light you plan to install.

Position your first puck light fixture between the markings you made under the cabinet. Keep the toggle switch toward the front cabinet for easy access. Remove the light bulb and lens if you need better access to the fixture’s mounting screws.

Drill a hole into the cabinet's underside, using the mounting screw hole nearest the front of the cabinet as your guide. Use a drill bit slightly smaller than the mounting screw.

Fasten the first screw in place securely enough to hold the puck, but leave enough play so you can fine-tune the position before drilling for and fastening the rest of screws.