How to install a GFCI outlet with 4 wires (AVOID Doing This!)

Installing a Ground Fault Circuit Interrupter outlet can be challenging, especially if you’re not a pro electrician. The good news is that it’s not as complicated as it seems.  

If you’re looking to install a GFCI outlet, you’re on the right page. So, let’s get started with how to install a GFCI outlet with 4 wires.



What Is a GFCI Outlet?

A GFCI outlet is basically an outlet that has built-in circuit protection. If there is a problem, the outlet will stop working.

The purpose of the GFCI outlet is to help protect from house fires and make sure that you don’t shock yourself. This is essential when you need electricity in a neighborhood of damp or wet conditions. This includes bathrooms, washing rooms, and kitchens. Local code often requires that you install GFCI outlets in these areas instead of standard outlets.  It also protects you against broken devices. While they won’t always prevent shocks, they tend to make them shorter so they definitely have their advantages over regular outlets.

These outlets come in different variations, including weather and tamper-proof editions.

 GFCI outlets are easy to install but sometimes need a permit and can be installed by most homeowners with basic knowledge and tools. 

 Tools needed

– Screwdriver

– Wire strippers

– Wire cutters

– Length of ground rod wire

– Hammer

– Drill

– Socket wrench set

– Magnetic screwdriver

– Metal tape

– Ground rod

– Match the GFCI with the breaker so that they have the same amps. 

Where to install the GFCI outlet

Where to install the outlet is very important.

If you’re installing a GFCI outlet in your kitchen or in a bathroom, there might be requirements in your local code that state that you have to keep a distance from certain objects. For example, often it is not allowed to install an outlet near a bath. Check your local code to make sure that you are allowed to install an outlet in the area where you want one. The manufacturer often also includes instructions and can indicate where you can install one.

Install The GFCI outlet with four wires

Start by turning off the power and installing the wires. Use a stud finder if you still have to drill to get them out of the wall. This makes sure that you don’t get in contact with other wires.

Once that is done, you will need to strip the top of the cable so that you can easily insert them into the GFCI outlet later on. Cables have a plastic cover that protects them but this needs to be removed before you can make contact with the outlet. This is done with a wire stripper. Most GFCI outlets have instructions for how long the stripped part has to be.

The main challenge is finding the right way to connect the cables to the outlet.

On the outlet, we see 2 parts. One part will be marked “line”, and the other (generally with tape over) is marked as “load”. Turn the power on and use an electrical tester. This will allow you to see which wire has to go to the line side. If you get a signal, it means that there is electricity on this wire and it has to go to the line side. There should be 2 wires of the same color as well. One of them has to go to the line side and the other wire to the load side.

The other wire that has a unique color has to go to the load side of the outlet. This neutral wire shouldn’t light up your tester. Then it is time to attach the fourth and final (ground) wire. 

Turn the power back off.  Install the wires as we discussed before. 

Then you can install the wires using a screwdriver. Don’t overtighten the screws.

Once this is done, we can turn the power back on and use a tester to see if everything is properly installed and if the grounding is properly working. If this works, you can turn the power back off and install the outlet in the wall. This is often done with screws as well. Be careful that you don’t damage anything when you install it. The last step is to add the cover. Make sure to test the outlet one final time before you add an electrical device. In some instances, an inspector will have to sign off on your work. 

GFCI Outlet Installation Tips

– Always turn off the electricity at the circuit breaker before installing the GFCI outlet. Wear protective equipment such as goggles and workers’ boots. Keep children and pets away while you’re working inside and outside your home.

Do not touch the wires after they’re installed in the wall. This will keep you from getting shocked and will prevent you from damaging the wires.

Make sure the outlet is installed properly. Inspect the outlet with a bright light and look for any damage to the wall. This will help you avoid any problems with your outlet and make sure it’s working properly.

– Use a large box if you have to. This will help keep the wires organized and make it easier for you to get it in the wall.

– Wrap the wires neatly. This will keep them from getting damaged and also give you a clear path for the electrical wires to go into the box.

– Make sure to keep the ground wire connected to the grounding rod. This will help protect your home from a fire.

– Don’t forget to use the correct color code for each wire. This will help you keep track of each wire and make it easier to install the outlet.

– Use a GFCI outlet with a GFCI breaker.

Make sure to test the outlet before you use it. If it is installed incorrectly, it can break appliances. We have discussed how you can do this HERE.


Installing a Ground Fault Circuit Interrupter outlet can increase the safety of your home. In this post, we have outlined some steps that you can take to install one. This will make sure that you can do this yourself if you have some knowledge about electricity. Check the instructions of the outlet that you bought as they might mention other steps. Make sure to wear protective equipment and turn the power off when needed.