Adding an Electrical Outlet to an Existing Run

Whenever you work with electricity, whether it’s a simple project or not, it’s best to know exactly what you’re doing before you start. That said, adding an electrical outlet isn’t that complicated. If you have an existing run, it won’t take a lot of your time. Furthermore, it’s safer to add an electrical outlet than it is to pack a store-bought power strip. Power strips can increase the risk of fires if not used correctly, especially if you have multiple high-intensity electronics attached to them.

Here we have an ideal situation—the drywall on one side of the wall has been removed and the wiring is exposed. But, save for installing a new electrical box, the process is largely the same (check out “How to Install an ‘Old-Work’ Electrical Box” to see how to install a new box when the drywall is intact).

To start, turn off the power to the existing outlet at the breaker panel, and test to ensure it’s off.

Then, remove the outlet and detach the wires.

Install the box for the new outlet, remove the “incoming” wires from the old box, and run them into the new one.

Then, cut a new length of the same-gauge cable to run between the new outlet and the old and feed it to the boxes, leaving about 8 in. of new cable in each box.

The cable needs to be secured to the studs, typically with wire staples, within 12 in. boxes that include cable clamps, or within 8 in. of boxes without cable clamps. When adding a new outlet without removing the drywall, there’s no requirement to secure the new cable to the studs.

To wire the new box, splice the wires from the new cable onto the old, along with pigtails that will connect to the new device. It’s best practice to cut the old exposed copper off the old wires and strip a fresh length to attach to the terminals.

Once the wires are connected (bare copper to the green screw, white to any silver screw, and black to any gold screw), fasten the receptacle, and repeat the splicing and connection process in the old box.

To finish, turn the breaker on and test both outlets to make sure everything is wired correctly.

More on Electrical:

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Master Carpenter: How to Wire a Bathroom – In this video series, electrician Cliff Popejoy explains how to run the rough electrical wiring for a bathroom. He’ll explain the necessary procedures for attaching outlet, switch and fixture boxes, tricks for running and stapling cable and last, how to prepare the boxes. Learn how to wire a bathroom here.