Find an electrical source in your kitchen to which you will connect your new lights’ wiring for power. You will most likely be able to use a nearby outlet for a feed. Try to use the closest outlet possible to make it easier to feed the wire from underneath the cabinet to the electrical box and new switch. Remember to turn off the circuit you are working with by turning it off at the main electrical box. If you’re unsure, you can also shut off power to the entire house. Tape a note on the main electrical panel to warn others not to reactivate it.
Never work with wiring and electrical components without shutting off power to the circuit, or you risk electrical shock. After shutting off power, use a voltage tester to check for any live current.
Consult local electrical codes in your area to be sure you are installing wiring safely and consistently with the requirements set forth by the codes.
Remove the wall plate for the existing outlet that you will use as a power source by removing the screw using a screwdriver. Pull out the receptacle and disconnect it from the wires. You are going to be widening this hole in the wall to make room for an on/off switch for your new lights. Place a two-gang outlet box over the hole and trace around it with a pencil. Depending on which side of the stud the existing box is installed, the existing outlet box will be on one side of the new box, either on the left or right side.. Use a drywall saw to cut into the wall along your traced lines to enlarge the hole. Remove the wires from the existing box and pull them out of the hole just enough so that they don’t fall back inside the wall. Pry the existing box from the stud, using a screwdriver or pry bar, and remove it from the hole.
Secure the wires to the wall with masking tape to keep them from falling back inside.