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Everything You Need to Know About GFCI Circuit Breakers

Ground Fault Circuit Interrupters (GFCIs)

A GFCI is a receptacle or circuit breaker and is used to increase safety in areas that are prone to the risk of electric shock. They will trip when current from the GFCI line side does not return through the neutral side. The GFCI measures the current from the line, through a load, and back to the neutral. This current needs to be the same. If current from the line does not return to the neutral (i.e. goes to ground instead), the GFCI will trip (power will be turned off coming out of the GFCI). It takes a mismatch of about 5 mA of current (5 milliamps or .005 A) to trip a GFCI.


Common GFCI Location Requirements

  • Unfinished basements
  • Kitchen countertops
  • Laundry, utility, and wet bar within six feet of a sink
  • Boathouses
  • Bathrooms
  • Garages and accessory buildings
  • Outdoors
  • Crawl spaces

Testing and Resetting a GFCI

When the test button is pushed or if the GFCI trips, power is shut off to the GFCI and protected receptacles. Pushing the reset button should restore power to the GFCI and receptacles connected to the GFCI load. If a GFCI has no power going to it (the GFCI line) then the test and reset button will not work. See Troubleshoot GFCI Receptacles. GFCIs should be tested about once a month. If it doesn’t trip when testing (but it has power to the line side), then it will need to be replaced.


Generally speaking, GFCI receptacles should be used when:

  • A circuit powers some receptacles that need GFCI protection and some that don’t
  • A receptacle is located far away from the panel box
  • You need few GFCI outlets and don’t want the expense of a high-quality GFCI breaker
  • Circuit breaker GFCIs are used as replacements for standard circuit breakers and provide GFCI protection to all receptacles on that individual circuit. The GFCI breaker can be built into or added onto your electrical panel and is typically a little larger and has its own test and reset buttons.

An entire circuit with a GFCI breaker can be used when:

  • Most or all outlets on a circuit need GFCI protection
  • Some outlet locations lack the space for bulky GFCI receptacles
  • You simply prefer the greater protection of the entire circuit
  • Specialty uses require a GFCI breaker, such as heated swimming pools
  • Operating a GFCI Breaker or Receptacle


Arc Fault Circuit Interrupter (AFCI)

If you’ve ever heard a buzzing noise when you turn a light switch, that noise is from wiring connections arcing. The arcing generates heat that could break down insulation around the wires, which could lead to an electrical fire. You should definitely look into fixing this issue immediately and install an Arc Fault Circuit Interrupter (AFCI) to prevent fire hazards.

ACFI uses advanced electronic technology to sense different arcing conditions. There are different technologies by different AFCI manufacturers to measure arcs but they all do the same thing. According to the NEC, AFCI senses line-to-line, line-to-neutral, and line-to-ground (parallel arcs). They could also sense arcing in series with one of the conductors (series arcs). AFCI protects the branch circuit wiring from arcing faults that could start an electrical fire.


Another type or arc fault protection is the Combination AFCI breakers (CAFI), which is the combination of parallel and series arc fault protection. Like other arc fault interrupter, this helps protect against fire hazards from arcing of damaged electrical wiring. Square D is a manufacturer of CAFI breakers which have a white test button on them.

Special AFCI circuit breakers protect outlets and device in the circuit. But you can also install AFCI outlets if your circuit is not protected. The NEC doesn’t require AFCI protection on existing installations. However, if you’re extending or updating your circuit, the NEC requires you to install AFCI protection. AFCI is now mandatory in all circuits feeding living spaces such as kitchens, bedrooms, laundry, etc. It’s a good point to note, though, that not all jurisdiction follow the NEC, in this case it would be good to research if AFCI protection is required in your community.


How to Install a Ground Fault Breaker

A ground fault circuit breaker is properly called a ground-fault circuit-interrupter breaker, or simply a GFCI breaker. It installs into a home’s service panel, or breaker box, and provides GFCI protection for the entire branch circuit it serves. This installation is commonly used as an alternative to installing GFCI receptacles (outlets) in specific locations where they are required by the local electrical code. A GFCI breaker installs much like a standard single-pole circuit breaker, but there are some important differences to be aware of. Also, the new GFCI breaker must be the proper type and brand for the service panel.

Safety Warning About Service Panels

Installing a circuit breaker involves working near equipment carrying deadly levels of electrical current. While the main circuit breaker and all of the branch circuits in the service panel will be shut off for the GFCI breaker installation, the incoming conductors from the utility service and the lugs (terminals) where the conductors connect to the panel remain live at all times. Never touch the service lines or the lugs while working in the service panel.

Choosing the Right GFCI Breaker

Service panels and breakers are made by many different manufacturers, and panels and breakers are not universally compatible. When installing a new breaker, the breaker must be compatible with the brand and type of panel you have. Consult the breaker and/or panel manufacturer for recommendations.

The new breaker also must carry the appropriate voltage and amperage ratings for the circuit it will protect. Standard branch circuits are rated for 120 volts and either 15 or 20 amps. Circuits rated for 15 amps usually have 14-gauge wiring but may have 12-gauge wiring; both are permissible. A 15-amp circuit must be protected by a 15-amp breaker. Circuits rated for 20 amps must have 12-gauge or larger circuit wiring and must be protected by a 20-amp breaker. Never use a 20-amp breaker on a 15-amp circuit.

Difference Between Standard and GFCI Breakers

Both standard and GFCI breakers are single-pole breakers that occupy one slot on a service panel and connect to one “hot” circuit wire, usually a black wire. The main difference between the two types of breakers involves the neutral connection. With a standard breaker, the neutral circuit wire (usually white) connects to the neutral bus bar on the service panel; it does not connect to the breaker. With a GFCI breaker, the neutral circuit wire connects to the neutral terminal on the breaker. Most GFCI breakers also have a short, coiled, white neutral wire preinstalled on the breaker; this connects to the neutral bus on the panel.

Note: You must connect the hot circuit wire to the “hot” or “load” terminal on the GFCI breaker and connect the neutral circuit wire to the neutral terminal on the breaker. Mixing these up reverses the polarity of the circuit and may mean the breaker does not provide GFCI protection to the circuit—even if the breaker’s test button works normally.

Shutting Off the Power

The most important step for this project is shutting off the power to the service panel by switching off the main breaker. This turns off the power to the panel’s hot bus bars and to all of the branch circuits. It does not turn off the power to the utility service conductors coming in from the utility meter or the terminal lugs they connect to in the panel.