Dear Mr. Electrician: How is kitchen cabinet lighting installed?
Answer: There are several choices of kitchen cabinet lighting types and the wiring method will depend on the lights being used. Regardless of the type of lighting, the wiring must be approved for permanent installation in residential walls. For low voltage lights I still use Romex cable as it is approved and no inspector will question its use. NOTE: Some text links below go to applicable products on Ebay and Amazon.
The kitchen remodel job depicted in the photos below called for a combination of low voltage and line voltage kitchen cabinet lights.
You should shop around looking at the various types and styles of kitchen cabinet lighting. Some are low voltage which require the use of a transformer to lower the voltage from the standard household 120 volts down to 12 or 24 volts.
There is nothing wrong with the use of low voltage lights. However it is necessary to locate the transformer in an accessible location for future maintenance and repair. A transformer cannot be buried inside of a wall.
KITCHEN CABINET LIGHT FIXTURE WIRING
As part of your kitchen renovation you should apply for an electrical permit with your local building department. I usually make a simple drawing of existing and new outlets, lights, and switches to submit with my permit application. I also include a one page “Scope of Work” simply detailing the work to be done and the wiring methods.
In addition I submit a copy of the installation instructions for appliances and a copy of the kitchen cabinet detail drawings. It is best to find out ahead of time if there is a problem with your installation rather than fail inspection after you have done the work. Some of the requirements for light fixture (Luminaire) installation is found in article 410 in the National Electrical Code (NFPA 70).
Below are photos from a kitchen remodel that I did for a client several years ago. Only part of the kitchen is depicted below. The rest of the kitchen is shown in another post.
The photo above is the undercabinet lights from the top photo taken at a different angle. You can see that a Romex cable comes out of the wall for each of these 120 volt light fixtures. I had to install a recessed junction box to accommodate all of the undercabinet light fixture wires. See the two gang blue junction box further down below.
My first step was to open up the walls so that I could drill holes in the wall studs, mount some electrical boxes, and then pull wires. I drew some straight lines and cut the drywall at back splash height using my multi-function oscillating tool.
There was only two receptacles on this wall originally, one for the counter top and one for the refrigerator. The new counter top is bigger than the old one so an additional electrical outlet was needed as per article 210.52(C) in the National Electrical Code.
The same area all roughed-in for lights and outlets. I used Thomas and Betts adjustable metal boxes because I did not know what the final wall depth would be at the time of rough-in. One gang adjustable box Steel City #MB120ADJ, two gang #MB238ADJ. The client had not yet chosen a back splash material.
I installed a junction box under the counter top where a space had been left open for a chair. I had to put a junction box in order to extend the power and telephone so I added an outlet and a phone jack there. It fit right in to have another junction box in the same area. I needed the other two gang blue junction box to accommodate all of the wires for the under cabinet light fixtures as each light is fed with a separate home run.
At the time of the rough-in, all of the kitchen cabinet light fixtures had not been purchased yet. Consequently I had to try and anticipate all possible wiring needs after the cabinets are installed.
Notice how the access hole beneath the junction boxes was cut at a 45 degree angle. This was done to make it easier to patch using the same drywall piece that was removed.
I used Arlington Industries Remodel Power and Low Voltage Box #LVDR2 for the outlet and a telephone jack under the counter top.
The wiring hanging from the ceiling is for the low voltage recessed cabinet lights. I used standard Romex cable for the low voltage wiring because it is approved and rated to be installed in walls.
The wire on the left is the connection to the power transformer. The blue box in the upper left part of the wall is for the electrical outlet that the transformer will plug into. I used a Carlon #B121ADJH PVC adjustable box for that.
I left the wires hanging and discussed the lighting installation with the cabinet installers. I gave them one of the recessed lights so that they could cut the holes in the cabinets for the recessed lights. I figured that they could do a neater job of cutting the holes in their shop than I could on the job site.
I like the adjustable electrical boxes. Never a problem getting the box to the correct wall depth. Close shot of the Carlon #B121ADJH PVC adjustable box. The screw at the top center is the adjustment to bring the box further out or to push it into the wall.
During rough-in I leave the adjustable boxes extended out past the wall. I do this so whoever comes in to finish the back splash will have to cut around the boxes. If I kept the boxes recessed in the wall the holes that the installers cut out for the outlets would most likely not be big enough for the box to penetrate.
The under cabinet lighting wires were brought through holes in the drywall at the height of the bottom of the cabinets (Approximately 54″).
I used a new work low voltage ring for the telephone jack on the counter top. That is a two gang adjustable box next to it.