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Doing any kind of electrical work would always scare us as DIYers, and it paralyzed us from finishing our roman clay electric fireplace project for over a year and a half! Changing out light fixtures was one thing, but putting in a whole new outlet seemed like a daunting task. It wasn’t though. With some research and YouTube videos (which you definitely should watch!), adding an outlet to your existing circuit really isn’t that bad and something most of us can do on our own.
Tip: Some local ordinances require you to use an electrician so be sure you know your local laws before starting the project!
Materials
(1) Outlet
(1) Outlet Cover
Electrical Wire Gauge
The size and length will depend on your needs
Wire Nuts or Wago Connectors (as needed)
Electrical Tape
Drywall Knife or Multitool
Hacksaw (as needed)
Stud Finder
Needle Nose Pliers
Box cutter
Drill (as needed)
Pencil
Level
Turn Your Power Off
Always, always, always turn your power off at the breaker when doing any kind of electrical work. It’s the safest way to ensure you don’t get zapped! You can test the power is off at the outlets you’re working with by using a simple outlet tester, it’s the best safeguard you can buy.
Plan the Power Source
Adding an outlet to an existing circuit requires you to draw power from another outlet and not necessarily from running wire directly to your breaker (that’s possible, but not what we’re covering). The outlets within your room will most likely be set up in some sort of relay. You have power coming up from your breaker to just one of the outlets and then each additional outlet is connected to the previous, all drawing power from each other creating a circuit.
So, to add an outlet to the existing circuit, you just need to connect your new outlet to an existing one to get power. So, when thinking about where you’re going to put your new outlet, make sure it’s within shouting distance of an existing one so you can draw from its power.
For us, we needed an outlet in the middle of a wall sandwiched between two existing outlets so we could use it (and hide it) for our electric fireplace.
Choosing the Right Wire Gauge
As part of planning your power, you’ll also want to take note of what kind of wire you’ll need. Electrical wire for outlets come in different gauges (or widths) and you want to use the same exact gauge as your existing wiring. Going to something bigger or smaller could cause your breaker to trip, or new outlet to not work properly.
In most homes the indoor wiring is either on a 20 amp or 15 amp circuit. The amount of amps simply means how much power is being drawn to that set of outlets. Those amps then equal out to a wire gauge size to use. If you have a 15 amp circuit then you’ll need 14 gauge wire (normally white in color), and if you have a 20 amp circuit then you’ll need 12 gauge wire (normally yellow in color). 12 gauge wire can work on a 15 amp circuit, but only because it’s larger in size and carry that power capacity.
The easiest way to find out which one you need is by pulling out the outlet you’re drawing power from (make sure the power is turned off!) and taking a peak at the wire being used. The gauge size should be printed on the wire itself and you simply just need to purchase the same exact thing.
Cut a New Hole
Now that you know where you want the new outlet, you’ll need to put in a hole for the outlet box. Outlet boxes should go right next to a stud when available to give them more stability and so you know in the future where the wire is running. The easiest way is to take the new outlet box, turn it around, and trace around the back of it.
Don’t make the same mistake we did, though. Use a level to make sure the hole you're cutting is straight. Our outlet came out crooked, but it ended up being ok since it was going to be hidden behind the fireplace.
Once you’ve drawn on the wall for the new hole, use a drywall knife or multitool (we have the Ryobi and it worked great here) to make the space. Put in your new outlet box for a moment to ensure it fits and make any adjustments to the hole you need. It should be snug and not loose at all. Take the outlet box back out so you can start the next step.
As far as what kind of outlet box to get, you’ll want one that’s labeled “Old Work.” That refers to you adding onto existing electrical work. The other type of box you’ll see in the store are “New Work,” but that means it’s new construction. Those type of boxes typically have nails that go into the stud, but because you have to cut into the drywall, there’s no way to get to those nails effectively to secure it. So, they make the “Old Work” boxes just for that reason.
The outlet boxes come in different depths too, so be sure to pick something that’s deep enough to hold additional wire in the back, but will also fit in your wall. The boxes also come in different “gangs” or how many rows of outlets (ie 1 gang, 2 gang, etc).
Fish the Wire To the New Outlet
There are a few ways in which you can feed the electrical wire from the existing outlet to your new one:
from below (which we were able to do)
from above, or
from the side.
Obviously the cleanest way is to go from above or below so you don’t have to cut and patch any other drywall. That would mean you have a basement if it’s a first floor outlet, or a crawl space if you’re working on the second floor. If both those options aren’t available, you’d have to cut along the wall, then drill through the studs to fish the wire, and ultimately patch the wall back up. Not ideal, but sometimes may be the only way.
If you’re going from above or below, take careful measurement of where in the basement or crawl space you’ll need to drill from so the wire will land in the middle of the wall. We agonized over this, but glad we did as our first thought wasn’t the correct one! So before we actually drilled up through the floor, we measured multiple times to ensure we had it right.
When drilling your holes, make sure it’s large enough to fit your specific gauge of wire. We ended up with about a ¾” hole in the end.
Once you’ve drilled your holes, you can do a couple things to fish the wire. We used a metal rod and painter’s tape to poke the wire up, but if you’re going from above, you may need to tape a magnet onto your wire and fish it down that way. You essentially need to give some kind of weight or structure to the new wire so that you’re able to grab it.
Fish the Wire to the Existing Outlet
For the existing outlet, before you begin to fish it, check to see if you need to cut out the outlet box in order to get the new wire in. For us, there was no way to fish new wire into that outlet box, we just couldn’t see behind it. So, we had to cut out that existing box that was nailed into the stud. Using a hacksaw, we cut the nails and were able to remove the box. With that, the box was essentially ruined, so that’s why we bought the second outlet box.
Now that the old outlet box was removed, we used the same method as with the new hole to get the wire up to it.
Wire the New Outlet
Now comes actually wiring your outlets together. We started with the new outlet as that was easiest for us. The electrical wire that is fished up will have three wires inside it: black (hot), white (neutral), and copper (ground). These will all connect into the new outlet purchased for the project. Be sure to use the same amp outlet as the one you’re drawing power from.
To expose those three wires, gently cut a seam in the middle of the insulation (the white or yellow color) and peel it back like a banana about a foot or as far as you need to. You can cut that excess insulation off so it doesn’t get in the way.
Then, use the back of your new outlet as a guide for how long from the edge of the actual wires you need before stripping them (there should be a small diagram there). There are two methods to use when attaching the wires to the actual outlet: wrapped on the screws or “plugged” into the back. Either method will work, but usually wrapped around the screws is the most secure.
Once you’ve stripped your wire the length needed, take the needle nose pliers, place them at the edge of the wire, and then curl it in the shape of a “U”. Slowly loosen the screw on the outlet, hook the wire onto it and then screw it down. There should be no other wire insulation showing outside the screw.
Important: The black, or hot wire, should go on the side of the gold screws and the white, or neutral wire, should go on the side of the silver screws. When the time comes, you can also test to make sure you have this right with the outlet tester.
Use this same method for the ground wire, but the only difference is, it’s just copper so there’s no need to strip any insulation off.
Once the wires are all on tightly, take some electrical tape and wrap it around the edges for added insurance no prying fingers will get zapped if they reach in there for any reason.
Connect the Existing Outlet
If you had to break your original outlet box, this is a good time to install the new one. We used an “old/new work” combo box that could screw into the stud. It worked out extremely well, but before securing, be sure to drill pilot holes so the screws go in easier!
To wire the existing outlet, first see if there’s an open screw (the outlets have two screws on each side you probably noticed) one for incoming power and one for outgoing - that’s how the circuit and even light switches all get connected. If you have an open screw, use the same methodology as above. But, if both screws are taken (which may be the case), don’t fret!
In this case, you can use wire nuts or Wago connectors (which are definitely worth the extra couple bucks!). These will simply group the wires together and give you one output that can connect to the outlet. Regardless of which method you use, disconnect all the wires from the existing outlet. If the wires were wrapped around the screws, you’ll want to cut the ends off as they’re probably worn and you want to start with fresh wire.
Group like color wires together (ie black with black, white with white), but before twisting them together in a wire nut or using the Waygo connectors, take about 7 or 8 inches of excess wire you had from the new installation and use that as a bridge for your newly grouped wires. Be sure to strip both ends of the bridge wire just as you would any other. Once all 4 wires are twisted together (the two existing wires, the new wire, and the bridge wire), you can use the method of screwing on just the one connection to the outlet itself. Use this method for just the black and white wires.
For the ground wires, you can actually just twist your new one on to the other ground wires that are already there. Our ground wires also had a clamp on them that we first removed in order to twist them altogether.
You can now put all the excess wiring into the electrical box and put everything back together.
Test It!
The moment of truth! Turn the power back on at the breaker and then use the outlet tester on each outlet to make sure it: 1) has power, and 2) the wiring was done correctly. The outlet tester we bought had a very easy color code and light system that checked these two things in order to make sure everything was done correctly. If the tester looks good, then try to plug a light or something else in to make sure you’re good to go!
Conclusion
Once we started the work, this took us about 4 hours to complete. If we were to do it again, having gone through it, this would only really take a few hours to do. There’s quite a few steps, but the work goes by fast once you get the hang of it. Electrical work definitely won’t hang us up now on our next project!
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