GFCI Outlets: Everything You Need to Know

With the average American home having about 75 outlets, it is evident that outlets are an essential part of every home. However, one essential outlet every home needs are the GFCI outlet, and in this post, we will tell you all you need to know about the GFCI outlet.

GFCI is a device that is saving millions of American families from electrical shocks. This post will tell you all you need to know about this device, how it functions, and how to replace a faulty GFCI outlet.

What Is a GFCI Outlet?

GFCI Outlets


GFCI stands for Ground-Fault Circuit Interrupter, or also called ground fault outlet. This outlet is responsible for saving the life of everyone present in your home within the blink of an eye. The GFCI outlet acts swiftly (within 1/40th of a second). It automatically shuts off the outlet or connection in the case of a ground fault. Hence the name; ground fault circuit interrupter.

When To Use A GFCI?

According to the National Electrical Code, the law requires you to place GFCIs in areas where the electrical outlets are proximal to water. For example, you can find these outlets within 6 feet of a sink in the bathroom or kitchen. However, you would also find them in crawlspaces, basements, garages, outdoors, laundry areas, or areas where electrical products might come in contact with water.

You are also required to have a GFCI protection when a receptacle has a 150 to 250 volt supply from a 150-volt or less single-phase branch circuit.

How Do GFCIs work?

Let’s look at an example to make things easier. So, assuming you are working in your kitchen, you have your tap running while connecting a toaster to an outlet. Well, let’s say you mistakenly push the toaster over, and it falls into the sink while the tap is running. So, you try picking the toaster up while it is still connected to the outlet.

Well, suppose the outlet the toaster is connected to is a GFCI. In that case, the GFCI protection will automatically interrupt or cut power to the toaster. This means you can pick up the toaster from the sink safely.

On the other hand, if the outlet the toaster is connected to isn’t a GFCI, then when you try to pick the toaster up with no insulations on your hands, you will get electrocuted. It will also cut the power to any other outlet connected to its circuit.

So, this leads us to understand how a GFCI outlet works.

Every GFCI outlet features 5 main parts, these include the ground(the circular slot), neutral (the longest vertical slot), hot (the shortest vertical slot ), test button (usually colored red), and reset button (colored grey or the color of the receptacle).

So, what happens is that the GFCI has an in-built smart sensor that monitors the current and voltage flowing through the receptacle of the outlet. This chip is located between the hot and neutral slots of the outlet.

The sensor is constantly monitoring the current to ensure no loss above 4 to 5 milliamps. Once there is a current loss above 4 to 5 milliamps or a ground fault, the sensor automatically shuts off the power to the outlet to prevent an electric shock.

It is important to note that one Ground-Fault Circuit Interrupter outlet can protect multiple outlets on the same circuit. This means that if you have other outlets wired downstream off a GFCI, all those outlets will also go off if wired correctly to the GFCI.

What Is A Ground Fault?

A ground fault refers to the situation when conducting shorts to the ground. What this means is that electric current flows through an unconventional means (which is your body) to the ground. Electric current and electric power go through your body when this happens, which is how you experience electrocution. So, the whole aim of the GFCI is to prevent that from happening.

The GFCI constantly measures the power going through and out of the receptacle. It measures how much current is on the hot and neutral slots. When there is at least a four milliamp variation, it stops the flow of current immediately. It is important to note that it prevents the current flow way before the current flows through your body.

You might be wondering how does the GFCI detects this 4 milliamp change, right? Well, what happens is that with a GFCI protection, the current flows from the hot slot to the neutral slot. And the same current or that flows through the hot slot must flow out of the neutral slot.

So, when you plug your toaster into the receptacle, and then it falls into the water. You try to pick it up; what happens is that the current from the hot slot will be split into two; some of the current go through the neutral, and some are grounded through the water.

Once you touch the electrical appliance that has fallen into the water, the current grounded through the water will flow through your body, and the rest will flow through the neutral.

When the sensor between the hot and neutral slot detects that the difference in current flowing between the hot and neutral slot is above 4 milliamps or 5 milliamps, it will automatically shut off due to the ground fault.

This means that the GFCI is preventing any current above 4 milliamps from flowing through your body; Any electrical current greater than or equal to 6 milliamps is capable of causing electrical shock. The outlet ensures that you are fully GFCI protected by shutting down the GFCI ground fault circuit once there are a 4 to 5 milliamps current flow difference between the neutral and hot wire.

Types of GFCI Devices

There are three types of GFCI devices. These include the GFCI outlet, GFCI circuit breaker, and portable GFCI. However, the GFCI outlet and circuit breakers are the most commonly used devices at home and depending on the area of your home. You can either have a GFCI outlet or circuit breaker, or both. And in this post, we will take an in-depth look at the difference between both.

GFCI Outlets

A GFCI outlet will protect almost any electrical outlet (non-GFCI outlets) succeeding the GFCI in the same circuit as the GFCI outlet. It also protects the devices plugged into the GFCI outlet and the other non-GFCI outlets.

These outlets make it easy for you to test and reset your GFCI with the easy-to-use “Test” and “Reset” buttons. With this, you wouldn’t have to worry about opening up the panel to reset the circuit breaker. The GFCI outlet also has a green indicator light which indicates that the device is working.

GFCI Circuit Breaker

GFCI Circuit Breaker

GFCI circuit breakers, on the other hand, become useful when you need protection for areas that have a large ground faults potential. For example, a pool or a bathtub. These have much larger voltage and current ratings, making the circuit breakers ideal for installing bathroom receptacles to protect you in these areas.

Unlike GFCI outlets, circuit breaker GFCIs are installed directly on the breaker panel, which is the power supply unit of the home. Also, unlike a GFCI outlet which protects downstream outlets after the GFCI outlet, the circuit breakers provide GFCI protection to all outlets on that circuit.

Most GFCI circuit breakers come with an indicator window and a fault indicator. The indicator window tells you whether the circuit breaker is on or off. If it is on, then it means the indicator window will be illuminated.

On the other hand, the fault indicator is used to indicate whether the GFCI is a fault or not; if the fault indicator light is on, then it suggests that there is a problem with a GFCI. Also, with a GFCI circuit breaker, you will have to open the breaker panel to reset or test the GFCI circuit breaker.

Portable GFCI

Portable GFCI

Just as the name implies, a portable provides you with the benefits of a GFCI outlet in areas where there are no GFCI outlets installed. For example, suppose you are working on a remote site, and you need to enjoy the benefits of a GFCI.

In that case, you can use a portable GFCI instead of installing a whole GFCI outlet or GFCI circuit breaker. Then, all you need to do is connect the portable GFCI to the socket or outlet you want to protect. Next, you connect any device to the portable GFCI, and then you can protect yourself and the device from electric shocks.

Some portable Ground Fault Circuit Interrupters come with multiple receptacles to help you connect various devices, which can come in handy if you need to use multiple electrical devices at a go.

If you are boondocking in the wild or camping at sites where you will be connected to a power source or if you will be using a generator while in, then you want to get yourself a portable GFCI to help protect yourself and your appliances.

Frequently Asked Questions (FAQs)

What Is The Difference Between a GFCI Receptacle And A GFCI Outlet?

Just like other electrical receptacles, a GFCI receptacle and outlet are mostly used interchangeably. However, the main difference is that an outlet is a point through which electrical current flows out. Whiles a receptacle is the slot which the prongs of your electrical device enter.

What Is The Difference Between AFCI vs. a GFCI Outlet vs. GFI Outlet?

A GFCI is an outlet or a device that interrupts the electrical supply to an electrical appliance and other outlets when there is a ground fault or irregularities in the current. GFI is another name used to refer to a GFCI; however, a GFI is only present at the outlet of the GFCI and not the panel.

An AFCI, on the other hand, is another protection device, and it stands for Arc Fault Circuit Interrupter. This device breaks off the circuit when it detects an arc. An arc refers to a spark, which is sufficient enough to cause a fire in a home. An AFCI will cut off the circuit to prevent such occurrences.

An AFCI determines arc in two ways. These are planned arcs and unintentional arcs. Planned arcs occur when a switch is turned on and off. During the process of turning on or turning off your switch, there is a spark. On the other hand, unplanned angles occur when there is a problem with the wires in a circuit. For example, when a wire is about to tear, it can cause a spark.

An AFCI can detect and distinguish between planned arcs and unplanned arcs and take the necessary action. An AFCI will only react when an unplanned arc occurs and detects these unplanned arcs thanks to the load current sensor, and then immediately shut off the circuit to prevent any fire outbreak.

In summary, a GFCI receptacle breaks the circuit in the case of a ground fault, while an AFCI breaks the circuit in the case of an unplanned arc.

What Are The Uses Of The Reset and Test Button?

The test and reset button of a GFCI enables you to determine whether your GFCI is faulty or working correctly. To test your GFCI outlet, you want to press the “Test” button, which should turn on the indicator light. And then, once you press the “reset” button, the light should go off.

Another way to do this is to connect a light to your outlet and turn it on. After connecting the light to the outlet, press the “test” button; after doing this, your light should go off.

Once your light goes off, it indicates that the GFCI outlet is working properly. However, if the light doesn’t go off, this could indicate that the GFCI outlet is faulty and needs to be changed. After pressing the test button, press the “reset” button, and the light should turn back on. If the light fails to turn on after pressing the “reset” button, it can also indicate that the outlet is faulty.

How To Troubleshoot a GFCI Outlet Receptacle?

You can troubleshoot your GFCI outlet by using the “test” and “reset” buttons. We have outlined the steps in FAQ 3, so try and go through that. However, it is essential to troubleshoot your GFCI outlet always. If there is any defect, ensure to contact a professional to help you change the outlet. However, if you want to change yourself, we have outlined the steps in FAQ 5.

How to Install a GFCI Outlet Receptacle?

DISCLAIMER: We do not recommend you change your GFCI outlet on your own. We highly recommend you let a professional handle installing GFCI Outlets in your home. However, if you want to change the outlet on your own, we have outlined the steps below. 

Two main problems can cause a GFCI not to perform correctly. These can either be caused by no power to the outlet or a fault in the GFCI receptacles, which is why you need to test them at least once a month. That being said, let’s take a look at how to change a fault in your existing outlet.

How to Replace a Faulty GFCI Outlet


The first step in changing a faulty GFCI circuit is to turn off the power supply. This can be done by opening up your breaker panel and then shutting off the power of the home area where the GFCI is located. So, if the GFCI is located in the kitchen, you turn off the kitchen GFCI sub-circuit.


The next step is to open up the GFCI receptacles. To do this, you want to unscrew the screws holding the receptacle in place. Then you want to pull out the outlet and place it somewhere safe.


Once you have the receptacle out of the way, the next step is to test for any power problems that may be caused due to no power flowing to the GFCI. You want to take the receptacle out of the box and turn the circuit breaker back on to test this. Once you have your GFCI circuit breaker back on, you want to use a multimeter to test the power supply to the GFCI.

There are two terminals you want to test for power. These are the line terminals and the load terminals. The line and load terminals will be located on the GFCI.

To test the line terminals, place the probe of the multimeter on the neutral and hot terminals of the GFCI. The multimeter should indicate 120 V AC when placed on the hot and neutral terminals. You also want to place one probe on the neutral and ground terminal, and it should indicate 120 volts as well.

The next step will be to test the load terminals. To do this, you should place the multimeter’s probes on the load terminals. Again, no voltage should be indicated on the multimeter.

These two tests with the results specified above show that there is no power problem with your GFCI. However, if the results show otherwise, it indicates no power supplied to your GFCI.

Well, with cases where the fault is due to no power supply to the GFCI, we recommend you let a certified professional handle that. However, if the problem has to do with changing the GFCI, then you may do that on your own or contact a professional to do that for you.


If the fault is a result of the GFCI receptacle, then you want to go ahead and change the receptacle. To do this, you want to check the box size of the outlet and then get a GFCI with a similar box size from an electrical shop around.

Once you have that ready, the next step is to disconnect the old receptacle. But just before you do that, you want to mark your line terminals to ensure that you attach your new GFCI the same way it was done with the old GFCI. This is important because if you switch the line and load wires when hooking up your new GFCI, it will not work correctly.


Before disconnecting the old receptacle, do not forget to turn off the circuit breaker again. Once you have your circuit breaker turned off, you want to hold the GFCI receptacle and then unscrew the electrical wiring connected to the receptacle.

Once you have your old receptacle disconnected, you want to replace it with the new receptacle. Make sure that you tighten the load and line wires into their respective terminals to prevent any malfunction after you’ve fixed the receptacle.

Once you have your new receptacle placed, push it back into the box, place and tighten the cover plate in place, and then turn the breaker back on.

Test the new receptacle once you have your breaker back on using the steps outlined in FAQ 3.


GFCIs are must-haves in homes, RVs, and any place where you would be using electronic devices. You are assured that you will be protected from ground faults. Thousands of people die from electrocution.

Therefore, you want to ensure that you have you and your family protected by simply installing a GFCI circuit breaker or a GFCI outlet. For those of you going camping, we recommend you purchase a portable GFCI.

We hope you found this article helpful, and we hope we answered all your questions concerning GFCIs. If you have any contributions or suggestions, do not forget to leave a comment below. Also, if you will need help with anything concerning GFCIs, kindly give us a call.

Do not forget to share this post with your loved ones to help protect them and their homes from potential electrocutions. Finally, do not forget to leave a like if you found this post helpful.

Make sure you consult a professional if you are considering whether to install a GFCI or not.

Related Posts

Best 7500 Watt Generators

Best 50 AMP Generators