How to Install Inside Cabinet Lighting for a Bathroom Vanity

Position the undershelf lights in the desired location inside the vanity. Hold them in place and have an assistant plug them in. Adjust the spacing of the lights until they illuminate the interior to your liking. Unplug the lights and mark the position of the screw attachment holes for each light.

Trace back the best route for the light cord to take, out along the boards of the vanity and to the nearest outlet. Mark any holes that need to be made in the boards of the vanity, taking into account whether the electrical cord can detach from the light for easy passage, or if a hole will need to be made for the entire electrical plug.

Drill out the holes for the lighting screws, being careful not to drill through the boards completely. Drill out the holes for the passage of the electrical cord, drilling through the boards completely. Make sure the electrical cord is unplugged. Pass the electrical cord through the holes and attach it to the undershelf light.

Reposition the undershelf lights and attach them in their places with 1/2-inch wood screws. Tighten all screws in all lights firmly, being careful not to overtighten and snap the plastic light casing.

Run the electrical cord out from each light, keeping it stretched tight. Check to make sure the cord is not plugged in, then staple it in place against the boards of the vanity every 6 inches to keep the cord tight. Repeat until the cord exits the vanity. Plug the cord into the outlet.