AFCI breaker

What It Means

AFCI stands for arc fault circuit interrupter. The Electrical Safety Foundation International (ESFI) explains that it watches a circuit for arcing, the dangerous sparking that happens when wiring is damaged, overheated, stressed or worn, and cuts the power before a fire can start. Arcing can come from an old wire that has frayed or cracked, or from a nail or screw driven through a cable behind a wall. Most AFCIs are breakers in the panel, and ESFI notes they also come as outlets.

How It Sounds at Home

• "The bedroom breaker keeps tripping when I vacuum."
• "Is that one of the arc fault breakers?"
• "The new panel has AFCIs on all the bedrooms."

The Breakdown

Test it once a month, following ESFI

1. At the breaker box, find the AFCI breakers; each one has its own Test button on the breaker. An AFCI outlet has the button on its face.
2. Press Test. The AFCI should trip and the power on that circuit should go off.
3. Reset it the same way you'd reset any tripped breakerTripped breakerA circuit breaker that has switched itself off to cut power to one circuit, most often because too much was running on it at once. See more: handle fully to off, then back to on.
4. ESFI says an AFCI that won't trip when tested should be replaced. Have a licensed electrician do that.

Short version to try today. Buhata's own suggestion: note which breakers in your box are AFCIs, so you know what you're looking at the next time one trips.

AFCI and GFCI side by side

When one keeps tripping. An AFCI trips because it has sensed what looks like arcing somewhere on the circuit. Buhata's own advice: reset it once, and if it trips again, stop resetting it and call a licensed electrician to find the cause.

Good to Know

The testing and resetting are the only parts of this for a homeowner. NFPA says AFCIs and GFCIs should be installed by a qualified electrician, so never take off the panel's cover or change a breaker yourself. ESFI describes the code requirement as one for newly built homes. Buhata's own suggestion: in an older home, ask a licensed electrician which circuits have AFCI protection and what adding it would involve. If you smell burning or see sparks, stop using the circuit, and if there's smoke or fire, get everyone out and call 911 from outside.

Related Terms and Categories

• GFCI outlet

  An outlet with Test and Reset buttons that shuts off power in a fraction of a second when current leaks where it shouldn't, to protect people from shock.

• Tripped breaker

  A circuit breaker that has switched itself off to cut power to one circuit, most often because too much was running on it at once.

• Smoke detector testing

  Pressing a smoke alarm's test button once a month to make sure it sounds, and replacing the alarm 10 years after the date it was made.

• Fire escape plan

  A household's agreed way out in a fire: two exits from every room, an outside meeting place, and a drill practiced at least twice a year.

• Licensed contractor

  A contractor who holds the license your state or local government requires for the kind of work being done, which you can check before you hire.

• Fire extinguisher

  A handheld tank that sprays an agent to put out a small fire, labeled with the classes of fire (such as A, B and C) it is approved for.

Home maintenance and repairs