How to Install Under Cabinet Lighting
Before installing under cabinet lighting, turn off the power switch at the circuit breaker, and remove the electrical box. Then, place the light fixture in the exact location you plan to install it, and mark an X to indicate where you will run the cable. After running the cable into the the fixture, attach the cover and socket strip, then place the bulb into the strip. Next, run the cables into the electrical box hole, and screw the electrical box in place. Finally, connect the outlet and light switch to the electrical box, and screw on the wall plate.
Choose an under-cabinet lighting kit. There are many different types of light to consider. You can choose from LED, fluorescent, incandescent, halogen or Xenon lights. LED lights come in either fixed lengths or in a strip that can be cut. They reduce energy costs and do not require replacement bulbs. They last up to twenty years. Fluorescent bulbs are long-lasting and energy-efficient, but they are harder to conceal. Incandescent bulbs produce a soft, yellowish light and are the most inexpensive option. Their lifespan is short, and they aren't bright enough for utility lighting. Halogen bulbs are bright and shine completely white. They create much more heat than other bulbs, but they also last twice as long as incandescent bulbs. They are more expensive than fluorescent or incandescent. Xenon bulbs are similar to halogen bulbs, but they last longer and radiate less heat. Find your source of power. The lighting will require a power source. Plan how you will run cable to the lighting/fixture locations. Determine if you are prepared to run wires, cut holes into the wall, and create new electrical boxes. Alternatively, consider plugging the light fixture into existing outlets or finding battery powered lighting. Plugging in the lighting into an existing outlet means you have to decide how to camouflage the lighting's power cable. Consider hiring an electrician if you're uncomfortable tying the lighting to any electrical wiring. Make sure you are using a code-compliant source of electricity. Make sure the source of power you selected isn't dedicated to the refrigerator or any other kitchen appliances. You don't want to overload the circuit. Determine your layout. Lay your light on the countertop, underneath where you plan to do the installation. If you plan to run multiple lights, find lights that have a quick-connect cord. This cord will connect lights using only one power source. Most installations are usually above the sink, work areas, and small appliances. For the best lighting, place the lights as close as possible to the front of the cabinet. Some manufacturers suggest that multiple lights be at least 12 inches apart. Clear your workspace. Make sure the cabinets and counters are free from anything that might obstruct your work. If you need to go through your cabinets for wiring, make sure all the items are removed. Determine if you need a new electrical box. If you plan to add new wires or a light switches that to an existing kitchen outlet, make sure the electrical box that houses the outlet has enough room. You will have to replace the box with a larger one if it doesn't. Use the National Electrical Code to determine the size of the electrical box. Calculate the amount of wires, devices, and clamps you will put in the box. Add 1 cubic inch for each hot and neutral wire, 2 cubic inches for each device (such as a switch), 1 cubic inch for all ground wires, and 1 cubic inch for all clamps. Take this sum and multiply it by either 2 for 14-gauge wire or 2.25 for 12-gauge wire. This calculation will give you the minimum box requirement in cubic inches. You do not have to do calculations for plastic boxes as the volume is stamped inside of them. Turn off the power to the kitchen. Do this at the circuit breaker. Find the switch labeled kitchen and make sure it's off. Test to see if the power is turned off, plug in a device such as a lamp or radio into the outlet and see if it turns on. You can also use a receptacle tester on the outlet. The lights on the test will come on if any power still running into the outlet. While the circuit breaker may be labeled, make sure you test the outlet anyway. There may have been changes in the wiring since the box was installed, or the wiring may be defective. Remove the outlet from the electrical box. First, unscrew the wall plate that holds the outlet. Then, unscrew the outlet from the electrical box. Take the outlet out and disconnect any wires that are connected to it. The electrical box is nailed to a wall stud. Look around the electrical box to determine which side the stud is on. Use a flashlight if it's too dark to see. You don't want to saw through the stud when you are expanding the hole to hold new electrical box. Draw an outline of the new electrical box. Hold the new electrical box over the existing box in the wall so the expansion of the hole is on the side that isn't nailed to a stud. Use a pencil to make an outline of where you will cut with the drywall saw. Enlarge the hole. Use a drywall saw to cut along the tracing you made. Make sure you're not hitting any studs. Remove the old electrical box. Make sure that any wiring connected to the old electrical box is loose before removing it. Pulling out the box when the wires are tight will damage the wiring. Once you are sure that wires are loose, remove the old box by using a flat pry bar. Find the knockout in the back of the light fixture. A knockout is a pre-scored hole made to run wire easily without drilling extra holes. Take out the knockout plug or plate. There might be a plug or plate in the fixture's knockout hole. Use a screwdriver to either pry the plug loose or unscrew the plate. Plan where you will drill. Before drilling a hole in the wall so that you can run cables, you need to plot the spot. Place the light fixture in the exact location you plan to install it. Find the spot on the wall directly across from the light fixture's knockout hole. Draw an “X” on this spot using a pencil. Make sure that there isn't a stud located between where you plan to drill the hole behind the light fixture and the electrical box. A stud will prevent you from running the cable. If you do find a stud, draw another “X” on the other side. Be sure to erase the previous “X” so that you don't get confused. Drill a hole into the “X. ” The hole needs to be just big enough to run the cable, so it's best to use a ½-inch spade bit. Cut your cable. Measure the distance between the electrical box and the hole you drilled. Take the distance you measured and add 24 to the length. This is how much of the 12/2 nonmetallic cable you need to cut. Adding the length to measure gives the cable some slack when you run it through the wall. Run the cable into the hole you drilled. Go to the hole where the electrical box was and reach into the wall. Grab the cable hanging from the small hole you drilled. Once you have the cable, pull it through the electrical box hole. Take off the cover and socket strip on the light fixture. Take off everything until you have just the casing of the light fixture. Clearing the fixture will give you space to screw the fixture into the cabinets. Place the light fixture. Put the fixture where you plan to install it. Make sure it is lined with the edge of the cabinet or behind it. Attach the light fixture to the cabinet. Screw the fixture to the cabinet using the screws the manufacturer provided in the kit. Place a cable clamp in the fixture’s knockout hole. Insert a ½-inch nonmetallic cable clamp in the fixture's knockout hole to hold the cable in place and protect it from damage. Unscrew the plate that locks the clamp and place the clamp in the knockout hole. Once the clamp is in place, screw the plate back into it from the outside of the fixture. Run the cable into the fixture. Grab the cable hanging from the small hole in the wall and run it into the knockout hole of the fixture. Strip the cable. Use a wire stripper to remove the coating around the end of the cable that's in the fixture. Once stripped, connect the exposed wires to the corresponding wires in the light fixture: black-to-black, white-to-white, and bare copper to green. Do this by twisting orange wire connectors to the ends of the wires. Reattach the cover and socket strip on the light fixture. Make sure all the connections are secure and that there is no exposed wired. Once you reattach everything back to the light fixture, staple the cable to the cabinet using cable staples. Place the light bulbs you selected into the socket strip on the fixture.  Run the cables into the new electrical box. There will be two sets of cables: the cable that ran into the old electrical box and the cable you ran from the light fixture. Pull both cables through the new electrical box. Place the electrical box into the hole you created in the drywall. The fins on the outside of the box should rest firmly against the wall so that you can screw it in securely. Screw the electrical box into the wall. The box has fins that flip inside the wall when you screw it. Make sure you feel the fins flip as these secure the box to the wall. Use a GFCI outlet. A ground fault circuit interrupter outlet will help prevent dangerous shocks that could seriously injure or kill someone. Once installed, this outlet ground-fault circuit interrupter will shut off instantly if the circuit shorts or is overloaded. Connect the wires from the new outlet to the cables in the electrical box. Use wire strippers to remove the insulation on the cables. Once the wires are exposed, strip on the insulation on them as well. Connect the corresponding wires using an orange wire connector. Use a green pigtail connector to combine the copper wires from both cables and the outlet. Screw the white and black wire into the GFCI outlet. Make sure you combine the black and white wires from both cables and the outlet. Once they are combined, screw the free end of each of these wires into the corresponding terminal on the outlet. These terminals will be labeled “hot-wire line” and “white-wire line.” Connect the dimmer or light switch. If you are installing a light switch into the outlet, connect the yellow wire from the switch to a black wire coming from the light fixture cable. Attach the copper wire from the switch to the copper wire on the GFCI outlet. Connect the white wires together. Make sure you use cable connectors to combine all wires. Tuck in the wires. Once everything is connected, carefully pack the wires into the electrical box. Screw the outlet and switch to the electrical box. Screw the GFCI outlet into the electrical box. Once the outlet is secured, screw the wall plate into the electrical box. Turn the power back on. Once everything is secured and connected, turn the power on by flipping the kitchen switch at the circuit breaker. 
Choose an under-cabinet lighting kit. Find your source of power. Determine your layout. Clear your workspace. Determine if you need a new electrical box. Turn off the power to the kitchen. Remove the outlet from the electrical box. Draw an outline of the new electrical box. Enlarge the hole. Remove the old electrical box. Find the knockout in the back of the light fixture. Take out the knockout plug or plate. Plan where you will drill. Drill a hole into the “X. Cut your cable. Run the cable into the hole you drilled. Take off the cover and socket strip on the light fixture. Place the light fixture. Attach the light fixture to the cabinet. Place a cable clamp in the fixture’s knockout hole. Run the cable into the fixture. Strip the cable. Reattach the cover and socket strip on the light fixture. Place the light bulbs you selected into the socket strip on the fixture. Run the cables into the new electrical box. Place the electrical box into the hole you created in the drywall. Screw the electrical box into the wall. Use a GFCI outlet. Connect the wires from the new outlet to the cables in the electrical box. Screw the white and black wire into the GFCI outlet. Connect the dimmer or light switch. Tuck in the wires. Screw the GFCI outlet into the electrical box. Turn the power back on. 