Under Cabinet Lighting (LED or Xenon): Installation Tips!
UPDATED JULY 2017
Xenon Pucks (recessed):
To install LED or xenon under cabinet lighting pucks, the cabinet bottoms are simply drilled out (whatever spacing you prefer) with the correct size hole saw bit recommended by the manufacturer (the hole saw can be attached to an ordinary cordless drill). The puck light is then friction fit into the hole from the under side of the cabinet. The inside of the puck and it’s wiring is then exposed on the bottom inside of the cabinet as well as the the low voltage power feed that is fed into it during the cabinet install stage (see “electrical” below). All the wiring connections are done inside the cabinet and stapled or taped in an organized, low profile arrangement on the inside base of the cabinet. The last step is simply to install one of the standard melamine shelves that comes with the cabinet over top of the wiring. Grooves are cut out of the bottom face (you can use a circular saw set to a depth of about 3/8″) to allow room for the wiring. The shelf is carefully put in it’s place and attached from below with a couple of carefully placed screws.
Electrical (qualified electrician required):
There are two choices when running the wires for new under cabinet lighting pucks; in series, or parallel. If they are xenon pucks, they require a much higher electrical current, so it is best to wire them in parallel. This means that you must run a separate 18/2 low voltage wire from each puck (or group of 2 or depending on wattage), to a location where the transformer(s) can be hidden from view. I usually choose the sink cabinet to place one or two square (usually 4x4), surface mounted steel electrical boxes (with box covers). Inside these boxes is where the transformer(s) will be housed and the individual wires will be connected to the low voltage side of the transformer. The line voltage feed will also be terminating in this box. To this feed, the line voltage side of the transformers are connected. All electrical codes require the line voltage side to be “hard wired” within a grounded electrical box, but the transformers and low voltage side of the transformers may be located outside of these boxes in some cases (check local electrical codes). A wire on the line voltage side would run into the junction box where it would be connected to the switched puck light feed. I usually run the numerous low voltage wires required with xenon pucks, within the stud cavities to keep it looking neat and tidy. The electrical part of this installation is quite involved, so be sure to get your electrician to do this work.
If you choose to install LED pucks for your under cabinet lighting, the same procedure can be used to install them into the base of the upper cabinets, however the electrical can be much easier than the procedure above. As long as you have a regular wall receptacle near where you will be hiding your transformer, you only need to plug one end of the wire into the wall plug, and plug the other end into the first LED puck (or into the end of just one LED strip light). The first puck is then plugged into the next (in series) until you have a “daisy chain” of several. Most LED puck transformers can drive several pucks because they require as little as 1/10th the current required by xenon pucks. It is also for this reason, that there is no need to run separate wires to each group of pucks as you would for xenon. The wire that strings all these pucks together often also contains a switch that you can conceal out of site, to allow you to switch them on and off. If you want a bit more flexibility in switch placement and switch aesthetics, you can also wire a wall switch into the line voltage side of these circuits. This however, is something you will have to get your electrician to help you with, since it will require line voltage wire splicing inside of a grounded electrical box. The benefits of LED’s are not only their low power consumption, but also their long life. Some manufacturers claim they can last 5 to 10 times longer than regular halogen (xenon). They also radiate far less heat. This can be an advantage when pucks are installed under a cabinet that is used for food storage. Strip lighting can be even easier because you only need to glue or tape the strip to the rear of the cabinet bottom, and your done.
Have fun installing your under cabinet lighting pucks or strip lights!