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

Thursday, July 12, 2018

All circuit breakers provide “overcurrent protection.” This means that, if current in excess of the breaker’s rating in amps is flowing through the circuit, the breaker will trip and disconnect the circuit to avoid overheating the wiring or equipment it serves, which could potentially start a fire. 

    Breakers with a small colored button marked “TEST”—it could be white, yellow, green, or red—have a dual protective function. There are two primary types: GFCI (Ground Fault Circuit Interrupter) and AFCI (Arc Fault Circuit Interrupter). When the test button is pushed the device simulates the defect that it s designed to protect against, and trips the breaker to the middle position if functioning properly. To reset, you push the breaker switch all the way to “OFF” and and then back to “ON.” If nothing happens when the test button is pushed, that means the device is not functional and therefore not protecting the circuit in the way it was designed.

    The GFCI-breakers protect against ground faults, which is essentially current that is traveling off the intended circuit and may be shocking you. These breakers protect circuits for pools and spa tubs, along with receptacles in wet areas like bathrooms, kitchens, garages, and exterior. Because GFCI-protection can also be provided by GFCI-receptacles with “TEST” and “RESET” buttons in the center, GFCI-breakers are used less often in panels today, with GFCI-receptacles placed around the home in the wet areas instead. 

    AFCI-breakers protect against arc faults, which is when a frayed or damaged wire sparks across a gap in the wire, either along one wire or between two adjacent wires. Because arcing of wiring is known to be a leading cause of house fires, AFCI breakers have been required for bedroom circuits since early in this century, and more recently they are must be installed to protect virtually all the 120-volt receptacles in a home.

    Also, see our blog post Are Ground Fault Circuit Interrupters (GFCIs) really necessary and worth the trouble?

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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?

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 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 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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