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Of course, the best time to install wiring for undercabinet lights is during a kitchen remodel, before the walls are covered with drywall. But if you want undercabinet lighting and aren’t planning any major renovations, don’t despair. The wiring plan we show in this article is designed to work in almost any kitchen, and can be installed without visible damage to the walls. And since we’re using the inside of the base cabinets to run wires, you don’t even need access to a basement or attic.
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The National Electrical Code requires that non-metallic sheathed cable (one brand is Romex) be protected in areas where it's subject to abuse. Since we're running the cable in the back of cabinets where pots and pans could bump it, we've chosen to be safe and run the cable inside a flexible steel conduit (called "flex"). We'll show you how to cut and install flex and then how to pull the cable through it.
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Figure A: Undercabinet Wiring
Even though the wiring is simple, you’ll still have to tie in to a source of power to provide 120 volts for the lights. We’ll tell you how to locate a suitable circuit. But if you’re uncomfortable with this part of the job, consider hiring an electrician to bring power to the junction box.
Even though the wiring is simple, you’ll still have to tie in to a source of power to provide 120 volts for the lights. We’ll tell you how to locate a suitable circuit. But if you’re uncomfortable with this part of the job, consider hiring an electrician to bring power to the junction box.
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Figure B: Connections at Junction Box
You’ll just have to work a little harder to hook the fish tape with the hanger. Using your saw, ream the hole through the back of the cabinet at an angle to better fit the flex. Push the end of the flex into the wall and secure the flex with straps placed every 4-1/2 ft. and within 12 in. of every hole in the cabinet and within 12 in. of the junction box.
You’ll just have to work a little harder to hook the fish tape with the hanger. Using your saw, ream the hole through the back of the cabinet at an angle to better fit the flex. Push the end of the flex into the wall and secure the flex with straps placed every 4-1/2 ft. and within 12 in. of every hole in the cabinet and within 12 in. of the junction box.
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The top-of-the-line fixtures we’re installing use low-voltage xenon bulbs. The fixtures cost about $35 per linear foot, about 20 percent more than similar halogen fixtures.
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1. Find a nearby outlet in the wall opposite the backside of the cabinets and plug in a radio.
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Find the circuit by turning off circuit breakers until the radio goes off.
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2. Drill starter holes and cut a 12-in. hole in the back of the cabinet to gain easy access to the outlet (power source). Keep the cut shallow to avoid nicking wires.
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3. Attach flex connectors to a junction box according to your plan (Figure A) and screw it to the back of the cabinet. Align the connectors so the screws point out.
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4. Drill 1-1/8 in. holes in the cabinet sides and feed flex from the metal junction box to each switch and light location.
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5. Mark the flex and cut it off with a hacksaw to the desired length. Build a cutting guide as shown.
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6. Run a cable from the outlet (power source) to the junction box, stripping 12 in. of sheathing off each end. Staple it within 8 in. of the box.
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7. Pull cables through the flex. Use a fish tape for long runs. Leave plenty of cable for running up the walls to the light fixtures.
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8. Drill a 1/2-in. hole under the wall cabinet and push in the fish tape. Drill a 1-1/8 in. hole through the base cabinet and wall and push in a wire coat hanger to catch the fish tape. Pull the fish tape down, attach the cable and pull it up.
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9. Secure the cable to the fixture with a cable clamp. Connect the wires according to the manufacturer’s instructions.
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10. Screw the fixture to the cabinet bottom and fasten the cable to the cabinet with a standard staple and No. 4 sheet metal screws.
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11. Mark the switch box profile on the backsplash. Drill a series of holes with a glass bit and chip out the tile and wallboard.
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12. Push the cable into a remodeling box and mount it in the wall.
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13. Connect the dimmer or switch according to the manufacturer’s instructions. Fold the wires into the box and fasten the dimmer and cover plate.
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14. Connect the new wires to the existing wires in the outlet box, black to black (hot), white to white (neutral) and the bare ground wires. Reinstall the outlet.
Make sure you can use Romex in your area. In Chicago we have to use conduit. There is an exception: in many cases flex can be used with discrete wires pulled through it (for situations like remodeling recessed cans that can't be installed with conduit). We can't even use prewired like Greenfield.