What is a Ground Fault Circuit Interrupter?

A ground fault circuit interrupter (GFCI) is a device that can trip or shut off a circuit to protect a person from electrocution. GFCIs are usually installed in kitchens and bathrooms, as well as in the garage or some outdoor areas.

How Does a GFCI Work?

Electricity has a natural tendency to seek a path to the ground. A ground fault is a connection between an electrical conductor and a conductor that is or may become grounded, either intentionally or by accident.

All the electrical current that comes out of an outlet should flow back into the outlet. If that doesn’t happen, some of the current will seek a path to the ground. If it goes through a person, that individual can be electrocuted, which can result in serious injuries.

A ground fault circuit interrupter can detect a small difference in the amount of electricity flowing into and out of a circuit, even at a level too low for a fuse or circuit breaker to pick up on. If the difference meets or exceeds a specific threshold, the GFCI will turn off the circuit in a fraction of a second to prevent electrocution.

How Can GFCIs Protect Your Family at Home?

The most common type of GFCI is a receptacle type, which looks a lot like a typical wall outlet. A circuit breaker GFCI can protect all receptacles on that circuit. Temporary or portable GFCIs are typically used outdoors to prevent electrocution when a homeowner is using power tools or lawn and garden equipment.

Since water conducts electricity, the risk of electrocution is greater in areas where water is typically present than in other parts of the home. GFCIs should therefore be used in areas where electrical tools and appliances may come into contact with water or wet objects. Although some appliances have built-in GFCIs, many don’t.

When and How Should You Test GFCIs?

A GFCI circuit can become damaged or worn out, but the electrical receptacle may still work. If your house has one or more ground fault circuit interrupters, it’s important to check them on a regular basis to make sure they’re functioning properly and will be able to protect you or a member of your family if necessary. Most GFCIs should be checked once a month, but if you use a portable GFCI, you should always check it before you use it. 

To test a receptacle or circuit breaker GFCI, press the TEST button. That will shut off power to the circuit. If you’re testing a receptacle type GFCI, the RESET button should pop up. Press the button.

When you test a circuit breaker GFCI, the handle should move to the tripped position. Reset the handle.

If you notice a problem when you test a ground fault circuit interrupter, contact an electrician. The GFCI may need to be replaced.