If the breaker is made by Square D and has the “D inside a square” logo, then the purple test button indicates that it is a Dual Function (GFCI and CAFCI) breaker. A yellow test button means it’s a GFCI (Ground Fault Circuit Interrupter) breaker, and a white button means the breaker is an CAFCI (Combination Arc Fault Circuit Interrupter). Square D breakers that are more than about 20 years old with a red ‘TEST’ button are GFCI, and AFCI breakers (an earlier version of CAFCI) had green test buttons. Other brands, like Siemens and Cutler Hammer, use their own color code, most often red or white. 

     There is very tiny print of the front surface of the breaker, but concealed under the metal dead front when it is in place, that states which type of breaker it is; however, we do not recommend removing the dead front to check. The photo at the top of the page shows Dual Function breakers with the dead front removed and manufactuer’s description circled. 

    Eaton breakers are different. They are color coded AND have the type of breaker clearly printed on the surface of the breaker where it is visible with the dead front in place. Here’s an example below from one of the newer type plug-on neutral panels. Blue = Dual Function (CAFCI+GFCI), White = GFCI, and Green = CAFCI.

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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?  

• What is the difference between GFCI and AFCI circuit breakers? 

• 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 a Combination Arc Fault Circuit Interrupter (CAFCI) and an Arc Fault Circuit Interrupter (AFCI) circuit breaker?  

• 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 AFCI AND GFCI page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.