Placing a TV inside a custom built-in cabinet should not, under ordinary circumstances, present a great challenge. Unless there are no outlets in the cabinet. Then, you will have only two options for plugging in your TV. Either use an extension cord, or install an electrical outlet in the cabinet. And since an extension cord will no doubt be an unacceptable choice, you'll need to know how to install an outlet. You may need a few tips for installing it. If so, check out the recommended installation steps and tool list.
Step 1 – Locate Your Preferred Power Source
Before you can decide where to cut a hole in your cabinet for an electrical (romex) cable, you'll need to identify the electrical fixture you'll use as your power connection.If your cabinet is on the ground floor above an unfinished basement, you can use an outlet in the basement as your power source.
Step 2 - Decide Your Cabinet Wire Entry Hole Location
Because your cabinet is built into an existing interior wall, and since you'll need to bring your electrical wiring through that wall into the place inside your cabinet where you'll mount your outlet, you'll need to find a hollow in that wall adjacent to your cabinet. It will be through this hole that you'll bring the wiring into your cabinet.
If your power source will be in your basement, below your cabinet, your best bet will be to run the new wire through the cabinet's bottom surface. Use a stud finder to locate a space between two wall studs beneath your cabinet. Mark this space on the bottom surface of your cabinet. This is where you'll drill your entrance hole.
Step 3 – Mount Your Outlet Box
Drill a 1" hole through the bottom of your shelf, close enough to the rear shelf panel that the space between the two wall surfaces will be directly below the hole. Using a jigsaw, cut out a piece of the shelf panel that will allow a single-gang outlet box to fit snugly in the hole. Use a hammer and screwdriver to remove one of the knock-outs in the box. This will create a hole in the box through which you can bring your electrical wire.
Step 4 – Install Your Romex Cable
Install your electrical cable with one end of the cable inside your cabinet and the other end at your chosen outlet, or receptacle. Be sure you have enough cable at each end to attach the wires to your receptacle.
Step 5 – Connect Your Wiring
Find your power breaker box and shut off power to the receptacle you'll be connecting to. Strip 1" of sheathing from cable and insulation from the white, black wires. Connect the new wires to those in the receptacle, black to black, white to white, etc. Finally, connect the wires at the cabinet to the outlet terminals. When all connections have been made, attach the receptacle and electrical box solidly to the cabinet, and turn the power on at your breaker box.