From Work Safely
Before you tackle any part of this project, turn off the power to the circuit at the main electrical panel by switching off the breaker or removing the fuse.
Before touching any bare wires or terminals on a switch or outlet, use a voltage tester on all the wires to make sure the power is off (Photo 1).
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If you have old, fabric-insulated wiring, call an electrician to recommend safe connections. With wiring like this, there’s usually no ground wire and it’s hard to tell the hot wire from the neutral, because both are coated with black insulation.
Avoid Cutting Holes in the Wall
Need to put in a new electrical outlet, but hate the idea of cutting holes in your walls to run the cable? Maybe you don’t have to. If you can keep all your work within one “bay”—that is, the area between two studs—you can add an outlet quickly and easily, and without any cutting or patching mess.
The procedure we show here allowed us to center our TV against a wall in the family room that had no outlet. We could have run an ugly (and possibly dangerous) extension cord, but since there was already an outlet in the other side of that same wall (facing into an adjacent bedroom), we just added a new outlet in the family room, drawing power from the bedroom outlet.
Of course, this only works if you can use an outlet as a power source that’s opposite, or nearly opposite, the place where you want your new outlet. To determine whether you can safely use an existing outlet, follow the list below.
How to Find a Power Source
If a switch or outlet is on a circuit that often blows its
breaker or fuse, don’t make matters worse by adding yet another outlet to
the circuit.
Electrical codes restrict the number of lights or outlets that can be connected to one circuit. Typically, you can have no more than eight lights or outlets on a 15-amp circuit. To determine the amp rating of a circuit, just look at the number on its breaker or fuse in your main electrical panel.
Most electrical codes now require outlets in kitchens and bathrooms to be on separate 20-amp GFCI circuits. So before using the method we show here to add an outlet in a kitchen or bathroom, check with an electrical inspector. If you add an outlet to a kitchen or bath, it must be GFCI protected. Don’t power your new outlet from a kitchen or bathroom outlet.
Codes also limit the number of wires that can enter an electrical box, depending on the inside volume of the box and the gauge of the wires. The outlet-addition methods we show here are based on the most common wiring (14-gauge wire on a 15-amp circuit) and an 18-cu.-in. box (typical inside dimensions are about 2 in. x 3-1/4 in. x 3 in. deep). If the circuit is 20-amp—which means thicker, 12-gauge wire—or if the existing box is smaller than 18 cu. in., you can’t wire a new outlet as we show here unless you replace the existing box with a larger one. Plastic box sizes are stamped on the inside at the back. Always confirm the required box size with your local building inspector. In most regions, you have to obtain an electrical permit for this work from your local building department. This helps ensure a safe job.
Run the Cable
Once you’ve determined the outlet that you’ll
use as a power source and have shut it off, use an electronic stud finder to
locate the studs on both sides. You can put your new outlet anywhere between
these two studs.
Hold the face of the new electrical box against the wall where you want it to go, and trace around it with a pencil. Cut out the hole with a drywall saw. Note: Be sure to buy a “remodeling” box that can be secured to the drywall, not one that must be mounted on a stud.
Next, unscrew the existing outlet on the other side of the wall from its box (Photo 1) and punch out one of the knock-outs at the back of the box using a screwdriver. Then feed the new cable through the knock-out into the wall cavity (Photo 2). Feed in enough cable to reach the new outlet location—plus about 1 ft. Connect the wires of the new cable to the existing wires (Photo 3).
Pull the cable out through the new outlet hole in the wall (Photo 4) and feed it into the new box. Then mount the new box in the opening. Photos 3 and 5 show how the electrical connections are made. Finally, call the electrical inspector to check your work.
Step by Step Photos and Instructions 1 - 5
At Existing Outlet
1. Turn off the power at the main
panel, unscrew the outlet and use a voltage tester to double-check that the
power is off. With either lead touching a ground wire (bare copper), touch the
other lead first to the neutral terminals (silver colored), then to the hot
terminals (gold colored). If the light glows with either contact, the circuit
is still live. Find the right breaker and turn it off.
At Existing Outlet
2. Feed a
length of new cable through one of the knock-out holes at the back of the
existing box (punch out the hole with a screwdriver). Feed through enough cable
to reach the new box (Photo 4), plus an extra foot. Use 14-gauge wire for a
15-amp circuit.
At Existing Outlet
3. Strip
about 10 in. of plastic sheathing from the new cable to expose the black, white
and copper wires. Run the new cable, with sheathing, at least 2 in. up inside
the box, and double over the excess wires to help hold the cable in place.
Strip 5/8 in. of insulation off the ends and connect the wires from the new
cable to the existing bundles—white to white, black to black, ground to
ground. Use new wire connectors of adequate size for the four wires in each
bundle.
At New Outlet
Click image to enlarge.
4. Mark the opening for the new box and cut it out with a drywall saw. Fish for the new
cable with a hook made from a wire coat hanger. Pull the cable through the
opening cut in the wall. Then strip about 9 in. of sheathing off the end of the
cable, insert the cable so the sheath extends about 1 in. into the box and
mount the box in the wall as shown in Photo 5.
At New Outlet
5. Connect the new wires to the new outlet: white (neutral) wire to a
silver-colored terminal screw; black (hot) wire to a gold-colored terminal
screw; bare wire to the green grounding screw. Make sure the cable sheath
remains secured inside the box.