Everything to Know About GFCI Receptacles | Ask This Old House (2023)


In this video, This Old House master electrician Heath Eastman teaches host Kevin O'Connor everything he needs to know about ground fault circuit interrupters.

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Kevin O'Connor and master electrician Heath Eastman meet back at the shop to talk about GFCI outlets. After discussing what a GFCI is and what it does, Heath shows Kevin how it works, the different types of installations that may exist, and how to test a GFCI’s function.

What are GFCIs?
GCFIs exist to protect the user. These devices detect when current from the hot conductor contacts a non-current-carrying metal part and cut off power to the circuit.

This means that GFCIs detect when current escapes the circuit due to a short circuit, such as the wire touching a metal box, a plumbing pipe, or the user standing in a puddle of water when plugging something in. Rather than continuing to feed current into that object or person, the GFCI trips and prevent further flow of electricity.

Where They're Required
GFCIs are not new. They've been around since the 1960s, and as such, code requires them in certain places. Typically required spaces include kitchens, bathrooms, and outdoor outlets. Anywhere water is usually present from a sink, shower, or toilet, or environmental causes like rain, snow, and dew, are locations where GFCIs are typically required.

How They Work
GFCIs operate by sensing the amount of current is being used by a device. The device looks for the same amount of current coming into the device and back out of the device. If the amount of current drops on the return side of the device, the GCFI will sense an imbalance (typically caused by a short of some sort) and trip the outlet off.

Types of GFCI Devices
There are typically two types of GFCI devices: outlets and breakers. GFCI outlets generally have a test and reset switch on their fronts, which is the tell-tale sign that a GFCI protects the circuit. Should the device trip, the reset button will jump outward, and the user must then reset it to reactivate the circuit beyond the outlet. Breakers work similarly, though they install inside the main electrical panel and protect the entire circuit.

GFCI Circuits
Just because an outlet doesn't have a test and reset button on its front doesn't mean it's not GFCI-protected. These devices are designed to shut off the entire circuit past the GFCI outlet, so if an outlet is on a GFCI-protected circuit, a short will cause the GFCI to trip regardless of where the short occurs. So, if a GFCI is installed first in a series of 5 outlets, a short at the 5th outlet will cause the GFCI to trip, protecting the entire circuit.

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Everything to Know About GFCI Receptacles | Ask This Old House


Foreign so what part of your electrical world are we talking about today, ground fault circuit, interrupters, ah, GFCI, GFCI, which is what so it's there for personal protection.

So a ground fault happens when we have something from the hot conductor making contact with a non-current carrying metal part, something like that, I know, it's a long-winded way of saying, the metal box, uh, a pipe or picture being around water, if you're going to plug something in and you're standing where it might be damp.

You've got a potential for current to leak somewhere if you're having a failure in that particular device.

So ideally, the current is running through the wires contained within the system, totally sealed.

But there are chances where you become part of that system.

Sure if you have a chord that chassis on appliance, that has a failure if something happens like that in the current Table to get out, we want to have some way to protect you.

Yeah, because that could be kind of nasty so been around for a while right, I mean, been around since I think the early 60s and been required in some areas in the 70s of the houses.

Yeah, in terms of where it's required.

You said, water and I think of these things of having to be in kitchens for sure, yeah, um and bathrooms, too.


Bathrooms are critical kitchens.

We need them outside.

You know, anywhere, you might plug something in Outdoors, your basement's damp anything like that garage, you know, plenty of other areas in the home as well.

So what's, the smarts.

How are they actually working? And what are they doing? So what they're doing is they operate by sensing, how much currents being used by a device.

So when you plug something in it's using a certain amount of current, this wants to see the same amount of current on both sides coming in and going back out if it sees something as small as 5 milliamps of a difference.

It knows it's losing current somewhere.

And it shuts down to protect you that's.

A tiny amount tiny, tiny amount it's thinking it went to water.

It went to a metal pipe.

It went somewhere that it shouldn't go.

So it shuts down.

So if I'm in the kitchen and I plug a blender in there should be a balance between that current right there exactly.

But if my hand is wet and I become part of that, some of that current comes to me.

It says out of balance shots right down, make sure you stay safe.

Okay, cool, um, I've, seen them before, but tell us how we know we are GFCI protected.

So the easiest way is we have one like this.

You can see those 10 custom reset buttons right in the middle, yep, that's, the easiest indicator.

And this particular one has an actual green light to tell you that it's on.

And we can plug this tester in to show you that it's, actually working because this lights up right there right and to verify that it's operating properly.

We can press that button on the top okay, there's still power to the device, but nothing coming out.

So when you plug something in it's, not going to work those buttons allow us to then put it back in place, yep back on gotcha.

And with it back on, we can now show that it's working no problem at all.


So if I see an outlet that looks like this, I know, I'm protected that at least that receptacle is protected, correct that receptacle right? How do I protect other receptors to get this question? A lot I, don't have GFI in my bathroom.

I know, I should have one I don't have one a couple of bathrooms.

One downstairs does why it actually protects from this? First one will protect that.

Second, one, wait so you're, telling me that this one, yep, which is GFCI I can tell that is connected to this one.

And therefore the protection comes with it exactly how do I know that.

So if you have a tester like that, go ahead and push the button.

This guy here that guy there.

So that turned that off and pop that can we do that again, that's so satisfying so that's working.

This is working right? But I know that if I were to, ah, so it was very common that if you had let's say, three bathrooms in the house, the very first bathroom closest to the panel, they'd run the power from the panel to the put the GFI there.

Then from this point, they'd go to the other receptacles.

So they'd come into What's called the line terminal on the GFCI and then come out on the load.

So it literally tells you where you have to go so line is up here wants to load down on the bottom, exactly so power coming into the line and back out to other receptacles to the load.

So you'd have your line conductor there and your lower down the bottom down there, right? So how this works is we'd have this coming in and going to this it's, the exact same thing.

So you're telling me, this is the line coming in right? Hooked it up to the place it says line.

And then this is the load coming out, and that goes to the next receptacle.

And then if we turn it around, and we see what we're looking at basically we're looking at what we've got here, it's doing the exact same thing, I know, that's protected because it's the right receptacle, but because it's tied to this, this is protected that's protected as well and I could do another one just a thumb receptacle all the way down going down, and those are all protected from that point forward, oh, that's.


Okay, if I don't wire, this correctly, do I lose my protection down.


Am I worried that I'm not protected.

You won't even get that far so that's.

Another common problem is when someone replaces these it's very easy to confuse which one's line and which one's load, if you put those wires on backwards, this won't, even reset, this will stay off.

And you won't even be able to turn that on this will never have power.


So when you put it back in, and you can't get it to reset and you're wondering, why chances are it got wired backwards? And then that means that this won't have power exactly all the way down.

Yeah, oh that's.

Definitely it locks you out and keeps you safe it'll fail, safe, oh, that's, very cool.


So that's.

Those are the only two ways I can tell that I protect it I can either physically look at it or I can go for the testing and say that this one's connected exactly and one other thing if you trip this, and you don't see one of these, but you see this shut off.

And you didn't have one of these Pop there's.

One other option is you might actually have A GFCI breaker in the panel.

Instead it's rare it's, not as common as these because they're more expensive, but does the same thing.

Nice, I, love.

It Heath.

Thank you.

All right.

Thanks for watching this whole house has got a video for just about every Home Improvement project.

So be sure to check out the others.

And if you'd like what you see click on the Subscribe button to make sure that you get our newest videos, right in your feed.


Everything to Know About GFCI Receptacles | Ask This Old House? ›

GFCI and GFI outlets are the same thing. GFCI stands for ground fault circuit interrupter, and GFI stands for ground fault interrupter, which are identical. You will encounter these terms interchangeably, but GFCI is a more common term.

What is the difference between a GFCI outlet and a GFI outlet? ›

GFCI and GFI outlets are the same thing. GFCI stands for ground fault circuit interrupter, and GFI stands for ground fault interrupter, which are identical. You will encounter these terms interchangeably, but GFCI is a more common term.

What should not be plugged into a GFCI outlet? ›

But don't plug big appliances such as refrigerators, freezers and sump pumps into a a GFCI outlet or circuit. It's also not a good idea to put lights on GFCI circuit – you don't want to be left in the dark if the circuit trips.

Do old houses need GFCI outlets? ›

Older homes are not required to have GFCI outlets unless the wiring is being updated, but it's a good idea to install them anyway. The NEC requires GFCIs on all exterior and bathroom receptacles (another term for outlets). GFCIs are also required on all receptacles serving kitchen countertops.

Should I replace old GFCI outlet? ›

If your outlets show any signs of cracks or discoloration, this could be a sign that your outlets need replacing. Any cracks in the outlet will expose the electrical wiring and can pose potential electrical hazards. We suggest replacing any damaged outlets with ground fault circuit interrupters for maximum protection.

What are the 3 types of GFCI? ›

Three types of GFCIs are designed for home use – wall receptacle, circuit breaker, and portable plug-in. All three are readily available, inexpensive, and fairly simple to install.

Do I need a GFCI breaker if I have a GFCI outlet? ›

GFCI and AFCI outlets connect directly to the circuit. You do not need both a GFCI outlet and a GFCI circuit breaker on the same circuit. GFCI circuit breakers are good installation options for new branch circuits, but they may not work properly on older, multiwire systems.

Is it OK to plug a refrigerator into a GFCI outlet? ›

There is no doubt that your family is safer with a GFCI on their refrigerator, than they are without it. The National Electrical Code requires that GFCI systems be grounded to ensure that a low-impedance fault path exists back to the OCPD.

Does a refrigerator need to be on a GFCI outlet? ›

A GFCI is not needed for a refrigerator in a kitchen so long as that refrigerator is not plugged into one of the general usage wall outlets, like what's above the counter. Some people may feel it's nice to have that protection, but it is not required.

Should a washer and dryer be plugged into a GFCI outlet? ›

There is no specific requirement in the NEC for the washing machine itself to have GFCI protection. Section 210.52(F) requires a receptacle outlet to be installed for the laundry area and it must be supplied by a 20-ampere branch circuit in accordance with 210.11(C)(2).

When should you not use a GFCI outlet? ›

To avoid nuisance tripping, a GFCI should not supply: Circuits longer than 100 feet. Fluorescent or other types of electric-discharge lighting fixtures. Permanently installed electric motors.

What if my old house doesn t have ground for the outlets? ›

If you have ungrounded outlets in your home, your safest option would be to rewire all of these outlets. Before rewiring, make sure to check every outlet to see if they're ungrounded. You can use a circuit tester to check each outlet to make sure they're wired correctly and if they're grounded.

Should an electrician install a GFCI outlet? ›

Do You Need an Electrician to Install a GFCI? If you have basic knowledge of electrical wiring, you may be able to install a GFCI outlet without professional help. However, if you have older wiring and outlets, it may be best to let a certified electrician handle the job.

How much does an electrician charge to replace a GFCI outlet? ›

The typical cost range for a GFCI outlet installation is $130 to $300, with customers paying a national average of $210. The primary factors that influence the price include the number of outlets, installation location, and the local cost of labor.

Can a handyman replace a GFCI outlet? ›

A licensed handyman is not allowed to do any electrical work if it connects to your home's electrical system directly unless the handyman also holds an electrician's license, which some of these providers do have issued.

What is the lifespan of a GFCI outlet? ›

GFCI outlets: Generally, GFCI outlets last somewhere between 15 to 25 years and should be replaced in this timeframe. While these outlets tend to work for a long time, you should test them regularly with the “Test” and “Reset” buttons.

How do I know which GFCI outlet to buy? ›

To find out what amperage GFCI outlet is correct, you need to find the breaker in your distribution panel and look at the rating printed on the handle AND you will need to determine that the wire gauge connected to that specific breaker is also correct.

How do I know what GFCI outlet I need? ›

  1. Locate the building's electrical panel box. Determine whether the building's electrical supply is regulated by fuses or by circuit breakers. ...
  2. Determine the current amperage requirements. Look at existing receptacles. ...
  3. For outdoor applications, determine the amp requirements first.

What should I look for in a GFCI outlet? ›

You can tell if a receptacle is a GFCI one or not by the way it looks. The GFCI is integrated into an electrical outlet and it typically has a red (or possibly white) reset button on the outlet's faceplate. The outlet monitors how much energy is going into it when in use.

Can you just replace a regular outlet with a GFCI outlet? ›

You can replace almost any electrical outlet with a GFCI outlet. Correctly wired GFCIs will also protect other outlets on the same circuit. While it's common to find GFCI outlets in bathrooms and kitchens, there are GFCI outlet requirements.

How many outlets can be on a 20 amp circuit? ›

A good rule of thumb is to assume that there will be a maximum power draw of 1.5 amps for each outlet, allowing 10 outlets for a single 20-amp circuit.

Will a tripped GFCI trip a breaker? ›

If your outlet breaker is tripping every time you use a hair dryer, and it never did that before, it's a sure sign you have a bad GFCI outlet. If this becomes the case, it's important to get it replaced as soon as possible!

Should microwave be on GFCI? ›

In the 2023 NEC, most dishwashers, electric ranges, wall-mounted ovens, microwave ovens, and counter-mounted cooking units will require GFCI protection.

Should dishwasher be on GFCI? ›

Kitchen dishwashers installed in dwelling units require GFCI protection whether hard wired or cord and plug connected.

Do you need a 15 or 20 amp GFCI for a refrigerator? ›

A modern refrigerator requires a dedicated 20-amp circuit.

Should a garbage disposal be on a GFCI? ›

The National Electrical Code (NEC) does not require a garbage disposal to have GFCI protection. GFCI protection for this appliance is optional. The vibration caused by the operation of a garbage disposal can cause electrical connections to separate.

How high should an outlet be behind a refrigerator? ›

For refrigerators, you have some flexibility. Typically, we mount these outlets about 48-inches off the floor.

Should a freezer be on a GFCI outlet? ›

However, GFCI's are prone to a phenomenon called "phantom tripping," meaning that they sometimes activate -shutting power off to the circuit - under normal, everyday voltage fluctuations. So freezers and refrigerators should never be plugged into GFCI's.

Does a hair dryer need a GFCI plug? ›

Since 1991, hair dryer manufacturers have been required to include ground fault circuit interrupters on hair dryer cords. GFCI outlets can sense unsafe electrical hazards and they automatically shut off power before a serious injury or electrocution can occur.

Does a laundry room need a GFCI? ›

GFCI Protection:

210.8(A)(10) – All 125V, 15a and 20a receptacles installed in “Laundry Areas” shall have GFCI protection. The NEC doesn't require GFCI protection for clothes washing machines specifically, but it does for “Laundry Areas.”

Does a washer outlet need to be on its own circuit? ›

According to most building codes, the answer is yes. A washing machine circuit is typically a 20-amp circuit served by a 10-gauge wire. It's important to have a dedicated circuit for your washing machine because the start-up current of these appliances can be three times its running current.

What is the downside to GFCI? ›

There are too many appliances being protected by the GFCI.

Sometimes tripping occurs when a GFCI circuit breaker is protecting multiple downstream receptacles. If several appliances are connected to the GFCI device, the cumulative effect of the appliance leakage currents may trip the GFCI.

How far does a outlet need to be from a sink to not be GFCI? ›

There are many places in 210.8 requiring GFCI protection, but the 6-foot rule only applies when sinks, tubs or showers are involved. Generally, all 15 or 20-amp, single phase, 125-volt receptacles “within 6 ft.” of a sink, tub or shower must be GFCI protected.

Can two GFCI outlets be on the same circuit? ›

You may use two or more GFCI rated outlets on one circuit if you like. However, if one trips or goes bad, all the outlets/GFCIs down the line will be affected. That's why you should test your GFCI's monthly to ensure proper operation.

Can I use 3 prong outlet without ground? ›

Ungrounded outlets in your home can cause big problems. This includes damaging appliances, electrical shock, and potentially even fires. Grounding your 3-prong outlets properly can ensure safety and efficiency within your home.

How much does it cost to convert an ungrounded outlet to grounded? ›

This project generally costs between $135 and $300 but can cost as little as $75 or as much as $485. Things start to get more expensive if your home doesn't have proper wiring. Sometimes, an electrician will need to add a grounding wire.

How much does it cost to ground wiring in a house? ›

Grounding wires cost $6 to $8 per linear foot, or roughly $130 to $170 per outlet. If you need to upgrade your knob and tube wiring—meaning, you need to rewire the whole house—costs rise rapidly. Rewiring a house costs $2 to $4 per square foot, or $4,000 to $8,000 to rewire a 2,000-square-foot home.

In what rooms should a GFCI receptacle be installed? ›

GFCI receptacles are required in bathrooms, garages, crawl spaces, basements, laundry rooms and areas where a water source is present.

Is it better to have GFCI outlet or breaker? ›

If you want to protect your entire electrical system from ground faults, then GFCI circuit breakers are the best choice. However, if you only need to protect individual outlets, then GFCI receptacles are a better option.

Should I put GFCI outlets everywhere? ›

GFCI outlets should be installed in any potentially wet or damp area such as kitchens, bathrooms, laundry rooms, outdoor spaces, basements, garages and workshops. Damp areas can make you prone to dangerous electric shock, but using a GFCI outlet can greatly reduce your risk of injury.

How long does it take to install a GFCI outlet? ›

Fortunately, installing a GFCI outlet is a fairly simple task that shouldn't take you more than 15 minutes. GFCI stands for Ground-fault circuit interrupter. These outlets contain a circuit breaker that will cut off the flow of electricity if there is a ground fault or if it detects a current leak.

Can one bad outlet affect others? ›

While one bad outlet doesn't always affect other outlets, a bad outlet can sometimes cause circuit breakers to trip, resulting in the other outlets not working as well.

Should bathrooms be GFCI or AFCI? ›

GFCI is the acronym for ground fault circuit interrupter, and it is the type of outlet required by electrical codes in areas where water is located, like your bathroom or kitchen.

What's the difference between a GFI and a GFCI? ›

Ground fault circuit interrupters (GFCI) and ground fault interrupters (GFI) are the exact same device under slightly different names. Though GFCI is more commonly used than GFI, the terms are interchangeable.

Do old GFCI outlets go bad? ›

All GFCI outlets have one little-known flaw: their circuitry eventually wears out, usually after about 10 years, at which point they no longer function properly.

How do you know when a GFCI outlet is bad? ›

If the GFCI won't reset or the button doesn't pop out when you press the “test” button, there may be no power to the GFCI or you may have a bad GFCI. Pro tip: If the “reset” button trips again every time you press it, there may be a dangerous current leak somewhere on the circuit.

What does a GFI outlet look like? ›

Standard GFCI receptacles look like conventional outlets, plus a “test” and a “reset” button on the faces of the outlets. Some receptacles come with an added feature of guide lights or a pilot light power status. In functionality, standard GFCI outlets protect you from electrocution if a ground fault were to occur.

Can you use a GFI outlet in a regular outlet? ›

You can replace almost any electrical outlet with a GFCI outlet. Correctly wired GFCIs will also protect other outlets on the same circuit.

What is a GFI outlet? ›

A ground fault circuit interrupter, called a GFCI or GFI, is an inexpensive electrical device that can either be installed in your electrical system or built into a power cord to protect you from severe electrical shocks. GFCIs have played a key role in reducing electrocutions.

What makes an outlet GFI? ›

GFCI stands for Ground Fault Circuit Interrupter. These are also referred to as GFIs, or Ground Fault Interrupters. A GFCI precisely monitors the balance of electrical current moving through a circuit. If the power goes where it shouldn't, like in a short, the GFCI immediately cuts off the electricity.

Should the light be on or off on a GFCI outlet? ›

The first light will flash green or red to indicate status. The second light will flash amber to indicate a trip or fault. When the device is first wired up or in a tripped condition, the green status indicator light and the amber indicator light should be on.

Where should GFCI be located? ›

GFCI outlets should be installed in any potentially wet or damp area such as kitchens, bathrooms, laundry rooms, outdoor spaces, basements, garages and workshops. Damp areas can make you prone to dangerous electric shock, but using a GFCI outlet can greatly reduce your risk of injury.

Is there a difference between indoor and outdoor GFCI outlets? ›

Outdoor electrical outlets differ from indoor outlets because they have watertight covers that protect the outlet even with a cord plugged in. Plus, the National Electrical Code requires all outdoor outlets to be GFCI outlets (ground fault circuit interrupter outlets).

Should I replace all my outlets with GFCI? ›

Can You Replace a Regular Outlet With a GFCI Outlet? If you want the added circuit protection, you should use GFCI outlets to replace regular outlets. Remember, regular outlets have no grounded protector. So, they can't save you from a short circuit in a faulty appliance or device.

Can I install a GFCI outlet myself? ›

Replacing a GFCI outlet is a DIY project that many homeowners can undertake with the proper preparation. It does involve some basic understanding of electricity, so those who have not done electrical work before should consider their comfort level before beginning this home improvement project.

Should a refrigerator be plugged into a GFCI outlet? ›

All commercial buildings/kitchens are required to have GFCI for refrigerators. See NEC 210.8(B)(2). In a Dwelling Unit (house or apartment) refrigerators located inside the kitchen do NOT have to have a GFCI.

Is it better to use a GFCI outlet or breaker? ›

It really depends on your needs and the local code requirements. If you want to protect your entire electrical system from ground faults, then GFCI circuit breakers are the best choice. However, if you only need to protect individual outlets, then GFCI receptacles are a better option.

What happens when a GFI blows? ›

GFCIs are designed to prevent bodily harm from electrical faults that could cause electricity to flow through you to ground. When a GFCI breaker trips, it It quickly disconnects the current flowing through an unintended ground path even if the amount of current is too small to trip a typical circuit breaker.

Do all GFCI outlets have buttons? ›

All GFCI outlets have a reset button (typically red) in the upper center of the outlet. Find the GFCI outlet near the outlet that tripped. You will be able to tell the problem outlet because the red reset button will have popped out.

Are all GFCI outlets the same? ›

There is no significant difference at all. When discussing GFCI receptacles, common conversations use the terms GFCI ground fault circuit interrupter outlets or simply a ground fault interrupter (GFI). They are generally counted as the exact same thing.

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