Install Under-Cabinet Lights

Under-cabinet lights make kitchen counters brighter and safer

In most of my customers’ homes (and I’m sure many Club members’ homes, too), the busiest work areas often are the most poorly lit. Basic kitchen lighting puts the fixture at the center of the ceiling, forcing cooks to work in shadow. This makes food preparation difficult and sometimes even dangerous.

If you have always dreamed of having a well-lit countertop but thought it was too late for your kitchen, this article is for you. I installed the under-cabinet lighting in this kitchen in a morning. The largest hole I had to patch was around 1 in. wide.

Before: General kitchen lighting puts the light behind you, which creates a shadow over your work surface.

When someone hires me to install under-cabinet lighting, I start by asking how much the bottom rail of the face frame hangs below the cabinet bottom. Since this is what hides the fixtures, the more overhang the better. These cabinets only had an inch, which is the same height as the fixtures. If that’s all you have, you may want to add a small valance along the cabinet bottom to hide the lights.

Start here
Retrofitting cabinets with lights is a three-step project: pick up power, install the switch and run all the cable with minimal damage. Although you may be tempted to pick up power from the countertop receptacles, you can’t use these circuits — it’s a code violation. This leaves you with two options: pick up power from a light circuit or a hidden receptacle, such as the one in the hanging cabinet for the over the range microwave oven.

In this home the most accessible and direct power source was the circuit that supplied the light over the kitchen sink. This switch shared a three-gang box with the switches for the dishwasher and disposer. To avoid the confusion of adding a fourth switch, I opted to pick up power there and run it to a new double-gang box that would include the new switch and an existing appliance receptacle. To avoid a cable fill violation (sticking too many cables in a box), I used the deepest double-gang box I could find. I selected a remodeler’s box with wings to mount into a finished wall so I didn’t have to fasten the box to a stud.

Plot your course
It pays to plan the entire cable routing before you start making holes. In this kitchen, I had to get the wire past the stove and the sink. I decided to route the cable over the stove through the cabinet above the microwave. To get past the sink, I ran the cable along the upper mounting strip inside the sink cabinet.

Minimizing surface damage is important when installing under-cabinet lights in a finished kitchen. I cut narrow slots for fishing cable along the bottom of the upper cabinets, so the repair would be concealed by the lights themselves.

I began the project by turning off the circuit breakers that served the various circuits in the boxes I would work on. These included the light circuit where I was picking up power, the dishwasher, the disposer and the appliance receptacle circuit. Once the breakers were off at the service panel, I tested the wires in the boxes with my Volt Ohm Meter (VOM) to be sure they had no power. A simple continuity tester would work too, but a VOM will sense low voltage whereas the voltage may not be sufficient to light the neon bulb in the continuity tester.

A box may contain more than one circuit., so test all the wires and make sure they are dead before you touch anything.

I knew I would place the new switch in the same location as one of the existing countertop receptacles, so I re-moved the receptacle from the single box. Then I cut the two nails holding the box and removed it from the wall. Since I do this type of work a lot, I use an in-line jigsaw for speed, but a mini-hacksaw will work fine. TIP: To make room for the blade to cut the nails, jam a large screwdriver blade between the box and the stud (once at the top and once at the bottom) and pry the box away from the stud about 1/16 in. With the old box out, I enlarged the opening for the new double-gang box.

Pry the box away from the stud with a screwdriver. Then cut the nails with an inline jigsaw (shown) or a mini-hacksaw.

Mark the hot cable by flagging it with red electrical tape. The long slot provides room to fish wires.

Fishing cables
When I fish cables, I rarely hit snags. Here’s how I do it.

Cut the tip off the end of the metal fish tape and straighten the tape. To connect the fish tape to the cable, slip about 4 in. of fish tape inside the cable sheathing, then wrap electrical tape tightly around both the cable and the fish tape. The electrical tape prevents the fish tape from pulling out, and the small profile rarely snags.

First, I ran a new cable between the two boxes. This provided power to the new box for all the under-cabinet lights. To get a cable under the wall cabinet, I cut a narrow slot in the wall just below the bottom of the cabinet. This way, the light fixture would cover the damage and I had plenty of space to fish wires.

I use flexible conduit to protect cables from moisture or damage inside cabinets. Although it is not required by code.

To minimize wall damage run cable through the wall cabinet over your range.

I fished a cable from the double-gang box through the stud bay up to the fixture. To get wire from one side of the stove to the other, I had to run the wire into the adjacent stud cavity. By notching one stud, I was able to get the wire over one stud bay, then I fished the cable into the cabinet above the microwave. I shielded the cable inside the cabinet with a length of flexible conduit. Code doesn’t require this, but it’s a safety measure that I prefer to take. Once I transferred the wire to the other side of the stove, I dropped the cable down to the spot where I would attach the next light.

Gang the fixtures with an NM connector under long cabinets to minimize holes in the walls.

Wire the ganged fixtures together by connecting same-color wires with properly sized twist connectors.

From the double-gang box, I fished a cable through the wall and into the cabinet under the kitchen sink. Working inside the cabinet, I drilled an access hole that would remain unseen. Because of the potential for the cable to get wet, I again placed the cable in flex conduit (held up with conduit clamps) where it was exposed under the sink. I followed the same procedure to get the wire up to the long cabinet, opening a horizontal slot that the light fixture would cover later. At this point, I had all the power feeds run through the kitchen.

Carefully pull the wires into the box as you press it into the wall. The power wire should be in the upper left.

From the double-gang box, I fished a cable through the wall and into the cabinet under the kitchen sink. Working inside the cabinet, I drilled an access hole that would remain unseen. Because of the potential for the cable to get wet, I again placed the cable in flex conduit (held up with conduit clamps) where it was exposed under the sink. I followed the same procedure to get the wire up to the long cabinet, opening a horizontal slot that the light fixture would cover later. At this point, I had all the power feeds run through the kitchen.

On long sections of cabinets, it is often more efficient to gang the light fixtures themselves instead of wiring each individually. Join the fixtures with a standard NM clamp. This allows the wire to run smoothly from one light to another with no damage to the finished wall.

Making connections
Once I had run the cable, the next step was to install the double-gang box. With the power coming into the box from the upper left location, I slid the wires into the box while pushing it into the finished wall. I turned the screws on the box clockwise to engage the wings that hold it tight in the wall. Next, I reinstalled the old receptacle in the new box and wired the new switch for the under-cabinet lights.

To wire the switch that controls the new lights, connect the grounds. Connect the incoming power supply wire to the switch and pigtail the other power (black) wires to the other leg of the switch. Connect the incoming neutral to the neutrals going to the lights. When I was done, I reconnected the appliance circuit wires to the original receptacle.

Pigtail from the power wire and run it to the new switch, then reconnect the wires that control the overhead lights.

Trim-head screws don’t require countersinking, and you can hide them with colored wood putty. Use an alignment block to flush the valance to the face frame, then pre-drill and secure with trim-head screws.

In the existing triple box, I had to remove the black wire feeding power to the switch and splice to it. I ran a pigtail from that splice back to the existing switch. All that was left was to join the various white (neutral) wires together using twist connectors and to do the same with the bare copper ground wires.

I mounted the lights with short sheet metal screws to prevent penetrating the cabinet bottom. Most fluorescent lights come with their own internal switches. You can use them to switch lights individually or activate all lights with the new wall switch.

Lighting Options
You have three choices when retrofitting a kitchen with under-cabinet lights: fluorescent, halogen (disc or linear) and xenon (disc or linear). Fluorescent lights are the least expensive to purchase and operate and they are the easiest to install. They require little power to operate, so there is less risk of overloading an existing lighting circuit. Fluorescent fixtures also light the area evenly, without the “spotted” look that can occur with other types of lights. If you find the light too stark, install “warm” replacement tubes. I prefer a tube that is called “outside light.”

The disc and linear halogen lights both provide bright high-color-quality light. They range in price from inexpensive to outrageous, and you get what you pay for. From an installation standpoint, halogen lights are available in very slim shapes that require little hiding by the cabinetry. The lights themselves are powered by a transformer you mount in one of the cabinets or in a closet or basement. If you have a lot of lights, you may need a separate circuit to power the transformer, which can result in additional wiring. The wires that power the lights themselves are low-voltage, so they can be exposed. Halogen lights can create a lot of heat when they are on and sometimes have a very short life span. Some require greater clearances to prevent fires when they are used in confined spaces. Always check the manufacturer’s specifications before installing under-cabinet halogen lights.

Relatively new on the market, xenon lights provide equal or greater illumination than halogen, with less heat. They are available in disc or linear configurations and are installed much like halogen. Use the same power considerations as with halogen — and be prepared to write a bigger check, too.

These low-voltage under-cabinet lights from Progress Lighting include track (top), strip (middle) and disc (bottom). They are available in halogen or xenon.

Want more?
Learn how to upgrade your kitchen sink here.
Build a beautiful kitchen island here.