What is a GFCI?

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What is a GFCI?

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. Greater use of GFCIs could further reduce electrocutions and mitigate thousands of electrical burn and shock injuries still occurring in and around the home each year.
GFCIs are usually installed where electrical circuits may inadvertently come into contact with water. They are most often found in kitchens, bathrooms and laundry rooms, or even on the exterior and in the garage where electric power tools might be used.

What is a ground fault?

A ground fault occurs when electricity travels outside an intended path and tries to get to the ground by the shortest route. If you touch electricity while you are grounded (touching the ground or something resting on the ground, like a ladder), your body becomes electricity’s shortest route to ground. You could also become part of electricity’s path to ground if you touch water that touches electricity. In either case, you could be hurt or even killed.
Because of this potential for shock, GFCI protection is used to protect human life. Circuit breakers and fuses only protect equipment—they will not protect people.

How does a GFCI work?

In a normal 120-volt outlet there are two vertical slots and a round hole between them. The longer slot is called “neutral,” while the shorter slot is “hot.” The hole between is called “ground.” The GFCI will “sense” the difference in the amount of electricity flowing into the circuit to that flowing out, even in amounts of current as small as 4 or 5 milliamps. The GFCI reacts quickly (less than one-tenth of a second) to trip or shut off the circuit.

What are the types of GFCIs?

Circuit Breaker

• A circuit breaker with a built-in GFCI may be installed in a panel box to add protection to the circuits it supplies.
• Protects against both a ground fault and a circuit overload
• Protects the wiring and every outlet, lighting fixture, or appliances on the branch circuit that it supplies.


• Used in place of the standard duplex receptacle
• Fits into a standard outlet box and protects against ground-faults for whatever is plugged into the outlet and other electrical outlets further “downstream” in the branch circuit.
• Can even replace older ungrounded, two-slot receptacles with new GFCI receptacles. Must use supplies label “NO EQUIPMENT GROUND GFCI PROTECTED” to identify that the receptacle is not ground
• Used where installed GFCIs are not practical.
• One type contains the GFCI circuitry in a plastic enclosure with plug blades in the back and receptacle slots in the front. It can be plugged into a receptacle, then the electrical product is plugged into the GFCI.
• Another type of portable GFCI is an extension cord combined with a GFCI. It adds flexibility in using receptacles that are not protected by GFCIs.

How should GFCIs be tested?

Many consumers don’t check their GFCIs to verify they are working. GFCIs are electronic devices that can be impaired or can wear out. The electrical receptacle in a GFCI may continue to function, even if the GFCI circuit no longer works. If this is the case, have a qualified electrician replace as soon as possible.

GFCIs should be tested monthly to guarantee they are in working condition. Whether you have a receptacle or circuit breaker GFCI, pushing the TEST button should turn off the power to the circuit. For the receptacle-type GFCI, pushing the TEST button should cause the RESET button to pop up. (Remember to push the RESET button to reestablish power and protection.) For the circuit breaker-type GFCI, pushing the TEST button should cause the handle to move to the tripped position. (Remember to reset the handle to reestablish power and protection.)

When should you test GFCIs?

GFCIs must be checked monthly to determine that they are operating properly. A portable GFCI should be used outdoors with various electrical power tools (i.e., drills, mowers, trimmers) and should be tested before each use!

Where should GFCIs be used?

It is recommended that GFCIs be installed in areas where appliances and power tools are used in close proximity to water. Tap water or wet objects are able to conduct electricity very easily and can connect your body to a ground potential, thus increasing your chances of receiving a shock from a ground fault. Appliances that have built-in GFCI protection, as now required for hair dryers, may not need additional GFCI protection, but there are still many appliances not equipped with GFCI protection.

How does a GFCI differ from an AFCI?

Arc-fault circuit interrupters (AFCIs) are a recently developed electrical safety device for homes to provide enhanced protection from fires resulting from unsafe home wiring conditions.

AFCIs should not be confused with ground-fault circuit interrupters or GFCIs. While both AFCIs and GFCIs are important safety devices, they have different functions. AFCIs are intended to address fire hazards; GFCIs address shock hazards.

It is very important for any home to have GFCI protection on outdoor receptacles, bathroom receptacles circuits, garage wall outlets, kitchen receptacles, and all receptacles in crawl spaces and unfinished basements. National Building Inspections regularly tests for GFCI’s during our regular home and commercial inspections. To book an inspection please call 866-655-6022, or visit our website www.nbiteam.com.

National Building Inspections