How to Install Electrical Outlet From Existing Outlet Easily

Do you want to make another electrical outlet for work purposes?

Do you want to wire a new electrical outlet because your old one is busted?

Or do you want to change your electrical outlet to make it safer and nicer?

Then you need to know how to do it very well to avoid any faults and injuries for both your building and your body.

Learning how to install electrical outlet from existing outlet is very helpful for you.

You will need to understand how to do it yourself even if you are hiring a professional to do this. There will be time when you need to redo your electrical outlet for many purposes. For example, you need to change your TV, computer, and other electrical equipment, it is wiser to use an electrical outlet to make it safer.

An electrical outlet is better than electrical power bars. If you are planning to use the electrical power bars, you may rethink it for one more time.

This complete and quite ‘long’ guide will help you now and in the future by mechanical and electrical steps. It is not complicated and simple enough if you have the idea how to do it.

Electrical Outlets vs Electrical Power Bars

Why is the electrical outlet better than power bars? Power bars along with its extension cords are giving a little ‘bad look’ to your environment. The concepts of electrical wiring are quite simple: safe, doing their job well, and looks tidy. By the means of tidy, we should do our best to hide any cable from the bare look.

The exposed cable can be cut and broken by anything if not carefully protected. Also, some power bars have a ‘colorful’ design which can attract children. Since they don’t know what it do, they may turn off your power bar when you are using it to supply your computer. Hence, your computer and electrical devices can be damaged.

Outlet Installation Tool

Preparation makes everything smoother. Prepare these tools first rather than preparing it when you are in the middle of the process. You can find the substitutes for these tools, as long as they come with the same function. These tools will help you a lot to install electrical outlets.


You know about this one. How would you make a hole in your wall without a drill? A drill is perfect to make a hole for your outlet’s screw. You need your outlet to hang on the wall firmly. The size of your drill is up to you depending on the outlet’s hole and screw size. Just for a tip, a drill about 0.75 inches or ¾” to 1” is perfect. If you have a cordless drill then it is very much better because you don’t need an extension cord. Otherwise, use anything you have to finish this task.


We have mentioned the size of the drill for a screw, hence we need something to make it “stick” to the wall. You can use anything, even a knife is able to tighten the screw. Just buy with your preferences. But keep in mind that it is wise to buy a “strong” one, not just a small screwdriver for an electronics board.

Saw or chainsaw

If you want to make a new outlet, you may need to make a hole in the wall. Not only to attach the outlet, but you also need to do cable routing to your new outlet. It is convenient to use a metal cutting blade that is able to cut the nails too.

Tape measure or ruler

You need to measure or just a ruler to calculate the distance, cable-routing, and make a mark for a hole on your wall to be perfectly fit with the new outlet. This task needs perfect precision or your work will be a bit unsightly.


You may need this if you want to cut the unneeded wire or remove an insulation wire. Any tools can be used but a tool with a speciality to cut a wire makes things far better.


This is just an additional tool. If you have a hard time routing your wire or finding it, this may come handy. Even your smartphone must have this feature.

Voltage detector or test pen or voltmeter

This tool comes in the last place because this is the last tool you may use in this process. After you have finished the outlet installation, don’t rush to use it on your devices. Some faults or incidents may occur if you are not doing it perfectly. Use this voltage detector or test pen to know whether the outlet functioned well.

Read also : how are transformers rated

Outlet Installation Materials

You have done a good job by preparing the necessary tools for this installation. Next, we will prepare all the materials. Don’t worry, what we will use here is not that much compared to the tools we prepared. There we are:

Electrical wire

Before buying the wire, you should check ‘how big’ your wire should be. You could check it on your circuit breaker. What to check exactly? You should know how much Ampere you have in your building. It is very dangerous to run up to 15 A current in your house with a wire which is capable of delivering only 10 A. Your wire can be burnt out and the worse, your house will be on fire.

You can browse in Google or ask a professional electrician about it. Just make sure that your wire has capability of delivering current more than the actual current. Say if your circuit breaker limits the current on 15A, you should prepare the wire capable of delivering current up to 15A or more for safer installation.

How long do we need to buy? It all depends on you how far the new outlet is from the circuit breaker or old outlet. For an electrical safety guide, you should be wiring it across the safest place from anything to reach it. An attic or below the floor is perfect to avoid any physical contact with anyone and anything. Take your tape measure to know how long your wire should be.

Plastic box

Not everyone uses this box to protect the outlets from inside the wall. But believe me, this plastic is very handy to place your outlet in the wall. Not only that, but this box can also make your wire tidier.

It is best to keep your wire longer that it needs to be because sometimes you need to pull the outlet if something is happening or when you want to disconnect the wire from the outlet. You can imagine how hard it is to disconnect a set of wire from an outlet if the wire can’t be pulled out even a centimeter.

The size and design are up to you, make sure it is perfectly fit with the hole you made and a bit bigger than the outlet.

New outlet

Right now you should have known your current on your circuit breaker because we need that number before buying any new outlet. Why does it have to be new? Because it is better to use a new one, maybe your old one is already rusting or something.

After you have known the current, may it be 15 or 20 Ampere, you should buy the new outlet with the same capacity or even higher than that. The reason? It is the same reason for buying the wire.

You can choose any variety of design, colors, shapes, sizes, and materials. Everything but the ampere specs is free to pick. After knowing the current, you need to know the type of new outlet you should use.

Let’s check your old outlet first. Is it able to connect with the three-prong cord? If you don’t know what it is, you could check it on Google. A simple explanation, a three-prong cord is a cord provided with the third prong which is able to make an alternative way for a current to flow when there is a fault in your electricity connection. Summary, it is for everyone and everything is safe.

For the recent National Electric Code, every outlet must have a grounding. If not, the GCFI outlet is needed here. The GCFI outlet is more expensive but it is needed to reduce the shock hazard. Remove the third prong and you will lose your safety.

GFCI or Ground Fault Circuit Interrupter or Residual Current Device (RCD) is able to detect a current which is flowing in the unintended path (person or water) and cut it off.

How to Install Electrical Outlet From Existing Outlet Easily
Source: Build My Own Cabin

How to Install Electrical Outlet From Existing Outlet

This guide will be quite long but I will make it shorter and detailed. Let’s start:

How to remove electrical outlet

This is the first thing you need to know in the guide on how to install an electrical outlet from an existing outlet, you need to remove the old one first. Therefore, let’s read the guide below:

  1. Turn off your electricity. This is very crucial for everyone who wants to do installation or maintenance. To avoid any faults and injuries, you should turn off your power from the circuit breaker. It is very dangerous if you get shocked by high voltage. After turning off, grab your voltmeter or voltage detector. A non-contact voltage detector is better here because you don’t need to touch the wire. Once you confirm that your electricity is completely turned off, you can continue your work. Don’t even try to touch the circuit breaker let alone turn it on, it is dangerous.
  2. Select the existing outlet you want to wire the new outlet into. Now you should already know which old outlet you want to replace with the new one. It is best if you want to install the new outlet directly through the wall where your old one is installed. For example, your new outlet will be in the room on the other side of the wall where your old outlet is installed. If the new outlet is quite far, you should try to install it in the same wall as your old outlet, preferably the wall without insulation. The insulation will make it harder to install than an empty wall.
  3. Remove the cover plate of the old outlet. Keep in mind that the power is still shut down. First remove the cover but leave one screw hanging for the later reinstall. There will be few screws to lock the outlet to the box. Remove them as well, all of it.
  4. Disconnect the wire connected to the old outlet. Now is the time to disconnect any wire from the old outlet. You should remember which wire is connected to which connector. Often the black wire is connected to the brass-colored screw, the white wire is connected to the silver-colored screw, and the insulation (ground) is connected to the green-colored ground screw. Just in case your country has different national wire color code, you should read it first or remember it before you disconnect everything.
  5. Cut the wire if they are too long. It depends on your outlet type. A common installation is to connect the wire to the back of the outlet rather than connect them to the side screws of the outlet. Some types have a small slot or chamber to use for your wire. Find your own way on this step. You could cut the wire if they are too long for your outlet.
  6. Remove the old box. Unless the new outlet will be almost directly through the wall from the old outlet, you need to remove the old box. Most of the boxes are locked with two nails, above and below the box. Grab your saw and start to cut the nails. But make sure that you don’t cut the wire because you will definitely need a professional here to re-wire. You can skip the removing the old box step if you don’t care about the old box or you won’t be using it. Just use any tool to remove the box from the wall, may it be saw, screwdriver, hammer, or anything strong.
  7. Pull the wire from the box. After removing the nails, next is to remove the wire from the box safely. Since we will use the new box, we will take away the old box and put the new one to the wall. Every box has its own configuration to hold the wire. Observe it carefully.

How to insert wire to outlet

After you remove the old outlet, it is time to connect the wire to the new outlet.

  1. Make a hole in the wall for the new box. Keep in mind that our box has a larger outer side so make sure your hole is smaller than it. The purpose is to make the outer side still outside of the hole, attached to your outer wall. If your hole is larger then the box will fall apart to the inside of the wall.
  2. Make sure the hole is not directly straight from the old outlet. If you plan to install a new outlet back-to-back perfectly with the old outlet, there may not be enough space for two boxes. True that I suggested that before, but give them space for a few inches. I didn’t mention that they have to be perfectly straight back-to-back though.
  3. Plug the wire to the new box. If your new outlet is not that far, as long as they are in the same wall, you have reduced the difficulty a lot. Assume that the new box is in the back of the old box, then you can plug your new wire to the old box besides the other wires. Push it more for about a foot of wire. Don’t worry, we will cut it for the necessary length later. Cut the other end of the wire for about a foot to the outside of the wall. We do this to make the wire form a loop inside the box to be able to go round along the box’s wire path. The next steps is needed if your outlet is too far from the old outlet.
  4. Route the cable inside the wall if the new outlet is too far. Only do this if your new outlet is quite far from the old outlet or in a different wall. Otherwise, skip this step and move on to the next step. Grab your drill because this is the only tool to help us draw the wire to the new outlet. Now drill some very small hole through the floor or ceiling or both at the edge of your wall and straight to the new outlet. Insert the rigid wire in (like a straightened coat hanger) so that it is visible in the attic or crawl space. If necessary, remove the baseboards or shoe molds on the floor so that when replacing them, the small holes will be closed. Be cautious that your rotating drill bit can and will “grab” a carpet and open it. The very small hole in the ceiling can be covered with toothpaste to keep it out.
  5. Make a hole in the wall and insert the wire to the inside of the wall. Your drill is still needed here to drill the wall. Keep in mind that we want to insert the wire into the wall, not through the other side of the wall. Your bit should be shorter than your wall. You will need to do the same if you are doing the same in the attic.
  6. Push the wire into the hole. Keep pushing one end of your wire until you can reach it from the old outlet location. After you are able to grab the wire, pull it about a foot length out of the wall. Cut the wire for the needed length and insert it through to the drilled hole you made before.
  7. Staple the wire. You should staple the wire to make sure it’s not moving. You can staple the wire for every 3 feet or something made for NM cable. If you don’t have a staple gun, you can use a hammer.

How to connect wire to outlet

Now you have done a very good job on inserting the wire to the new outlet. Now we will move to how to connect the wire to the new outlet.

  1. Peel the outer sheath of the new wire. Do this for about 4-6 inches from the end of the new wire. Pull the peeled sheath softly so the ‘conductor’ or ‘copper’ part of the wire is visible to get connected.
  2. Push the wire to the new slot. The new wire should be inserted to the back of the box so that the unpeeled part is inside the box. Place the box into the wall and screw it to the wall so it sticks firmly.
  3. Cut the existing wire. You may find three or even more wires in the existing outlet, thus you need wiring them together. Prepare the additional black, white, and ground wire for about 6 inches and remove their sheath. The color depends on your country’s national wire color code.
  4. Wiring the ground wires together. Now wire all the ground wires with a wire nut or something. Make sure that the wire is held firmly.
  5. Repeat the step for black and white wires.
  6. Connect the wire to their corresponding screw in the outlet. Ground cable to the green screw, black wire to the brass-colored screw, and white wire to the silver-colored screw.
  7. Push the outlet to the box and tighten the screw holding it. After we secure the wire connection, the final touch is to attach the outlet to the box and tighten them with screws.

Frequently Asked Questions

The questions below are the most asked questions about how to install electrical outlet from existing outlet

How do I add an electrical outlet to an existing outlet?

First, turn off your power using from your circuit breaker. Second, remove your existing outlet along with its box. Third, disconnect the wire. Last, put the new box and outlet, and then connect the wires to the new outlet.

How many outlets can you add to an existing outlet?

The Electrical Codes restricts how much lights or outlet that can be connected to the circuit, no more than 8 lights or electrical outlet if the building has 15 ampere.

Can I install an electrical outlet myself?

To do electrical outlet installation you need all the tools and materials. From the full guide above you will master it in minutes.

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