What is the difference between a Combination Arc Fault Circuit Interrupter (CAFCI) and an Arc Fault Circuit Interrupter (AFCI) circuit breaker?

Sunday, July 22, 2018

The CAFCI is a new version of the older ACFI breaker. Both trip like a standard circuit breaker when the circuit is overloaded with too much current or there is a short circuit, and the AFCI also trips when there is parallel arcing (hot-to-neutral or an arc to ground) in the protected circuit. Because arcing (you might call it “sparking”) in wiring is one of the the leading causes of house fires, this protection is important. Circuits serving bedrooms have been required to have AFCI-protection since the beginning of this century.

    But AFCI breakers did not recognize series arcing (between a small gap or frayed area in the same wire), so the combo-AFCI or CAFCI was developed, which has that additional capability. Beginning in 2008, the National Electric Code (NEC) has required the installation of combination-type ACFIs in all 15 and 20-amp circuits, with the exception of laundries, kitchens, bathroom, garages, and unfinished basements—which are locations where Ground Fault Circuit Interrupter, also called GFCI, protection of the circuits is required. CAFCI, AFCI, and GFCI breakers all have test buttons, like in the photo above.

    So, essentially, a CAFCI is the new and improved version of an AFCI. Older AFCI breakers by Square D/Homeline (pre-combo) have green or blue test buttons; and while both types of breakers by Eaton Cutler-Hammer are clearly marked on the front of the breaker, like in the photo above.The label indicating that a breaker is a COMBINATION AFCI is hidden behind the dead front (cover plate of the panel box) and noted in very small letters along with the other listing information on the face of the breaker for Square/Homeline breakers, like the one shown below. But they are recognizable by the white color of the test button. 

    Also, see our blog post What is the difference between GFCI and AFCI circuit breakers?

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Here’s links to a collection of our other blog posts about AFCI and GFCI RECEPTACLES AND CIRCUIT BREAKERS:

Does a septic pump or sump pump require a GFCI-receptacle?

 • What is the difference between what trips a GFCI (ground fault) receptacle and a circuit breaker?

Are Ground Fault Circuit Interrupters (GFCIs) really necessary and worth the trouble? 

What is the code requirement for GFCI protection for receptacles near a wet bar sink?

When was GFCI-protection for kitchen dishwasher receptacle outlet first required? 

When did arc fault circuit interrupter (AFCI) breakers first become required?

Does a washing machine receptacle outlet require GFCI protection?

My spa tub stopped working. What's wrong?  

How do I identify a combination AFCI (CAFCI) circuit breaker? 

What does "listed and labeled" mean for an electrical component? 

What electrical hazards does a Ground Fault Circuit Interrupter (GFCI) NOT protect against?  

Where are GFCI receptacle outlets required?

When were GFCI receptacle outlets first required?

What happens when you press the "TEST" button on a circuit breaker in an electric panel?

What is the difference between the electric service to a mobile home and a site built home? 

Why is there a wall switch next to the furnace or indoor unit of the air conditioner in the garage?

What is a Dual Function Circuit Interrupter (DFCI)? 

How I can tell if a receptacle outlet is tamper resistant?

What is the difference between "grounded" and "grounding" electrical conductors? 

What does it mean when a wire is "overstripped" at a circuit breaker?

Why is there a GFCI breaker in the electric panel for the bathroom shower light and exhaust fan?

What is the switch on the wall with two pushbuttons? 

How far apart should kitchen counter receptacles be spaced?  

How far above a kitchen countertop do electrical outlets have to be? 

How is it possible to provide both GFCI (Ground Fault Circuit Interrupter) and CAFCI (Combination Arc Fault Circuit Interrupter) protection for kitchen and laundry circuits?

My bathroom electric receptacle/outlet is dead and there are no tripped breakers in the electric panel. What's wrong?  

My GFCI reset button is hard to push and won't reset. What's wrong?

• Why do some breakers in my electric panel have a "TEST" button on them?

    Visit our ELECTRICAL page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.

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