Things You'll Need
14-2 in-wall electrical wiring
Metal outlet box
You can never predict where you might want to have an electric outlet, but there's a good chance that someday you'll want one in a location where there isn't one. If you need an outlet inside of a cabinet, you can add one by yourself with a little planning, some simple tools and a degree of common sense. When planning for the outlet, consider the location of existing outlets -- by tapping into an outlet that's directly below your cabinet you'll avoid having to cut through wall board and studs when routing the new power cable.
Turn off the power to the circuits you'll be working on at your home's circuit breaker panel.
Remove the screws from the cover of an existing outlet that's located below the cabinet where you want to install the new outlet. Loosen and remove the screws at the top and bottom of the outlet and pull the outlet out of the gang box as far as you can.
Drill a hole through the back of the cabinet, and through the wall behind, at the spot where you want to mount the new outlet
Fish a wire down the wall until you reach the existing gang box. Tape the end of a length of 14-2 cable to the wire and pull the wire up through the wall to the hole. Pull about three inches out of the hole at the top.
Cut the wire to length at the bottom and remove half an inch of insulation from the ends of the black and white wires in the cable. Wrap the black wire around the brass screw on the switch and the white wire around the silver screw. Push the outlet back into the gang box and screw it in place.
Feed the wire in the cabinet into the rear opening of a metal gang box. Place the gang box against the back wall of the cabinet and screw it to the wall with wood screws placed through the screw holes in the gang box.
Attach the black and white wires to the brass and silver screws, respectively, of the new outlet. Place the outlet in the box and attach with screws. Place a cover on the outlet. Turn on the power to use the outlet.