Q & A: Arc Fault Circuit Interrupters

Department:  Public  
Type:  Fact Sheets  

Now more than ever, our homes are being dramatically transformed by in the introduction of new electrical devices.  Unfortunately, the electrical systems of many existing homes are simply overwhelmed by these modern electrical demands, putting them at greater risk of arc faults and arc-induced fires.

 

What is an arc fault?

  • An arc fault is a dangerous electrical problem caused by damaged, overheated, or stressed electrical wiring or devices. 
  • Arc faults can occur when older wires become frayed or cracked, when a nail or screw damages a wire behind a wall, or when outlets or circuits are overburdened.

 

Is this a common problem?

  • More than 56% of the nearly 51,000 home electrical fires that occur in the U.S. each year involve arcing of home electrical equipment.  These fires result in more than 1,000 deaths and injuries and more than $700 million in property damage.

 

What are arc fault circuit interrupters, or AFCIs?

  • Arc fault circuit interrupters, or AFCIs, are devices that provide a higher level of protection by detecting hazardous arcing conditions and shutting down the electricity before a fire can start.

 

What are the different types of AFCIs?

  • Branch/feeder AFCIs, the most common type of AFCIs, replace standard circuit breakers in your home’s electrical service panel and provides arc-fault protecton to the entire branch-circuit from the service panel to the outlets. 
  • Outlet AFCIs are receptacles that provide protection to power cords and things that are plugged into the receptacle.
  • Combination AFCIs combine the features of branch/feeder and outlet AFCIs and detect arching faults in the complete circuit.

 

Are AFCIs effective?

  • The U.S. Consumer Product Safety Commission (CPSC) estimates that AFCIs could prevent more than 50 percent of the electrical fires that occur every year.
  • Beginning with the 2008 edition, the National Electrical Code (NEC) has expanded the requirements for AFCI installation beyond bedroom circuits to additional areas of the home, including dining rooms and family rooms.

 

How much do AFCIs cost?

  • These devices can be purchased at any local electrical distributor, hardware store, and home improvement center across the country for approximately $35 each.
  • Depending on the size of a given home, the cost for installing additional AFCI protection is $140 - $350.

 

Can I install them myself?

  • AFCIs should only be installed or replaced by a licensed, qualified electrician.

 

What does the TEST button do?

  • AFCIs should be tested after installation and once each month to make sure they are working properly.
  • Follow the device manufacturer’s testing instructions.
  • If the device does not trip when tested, it should be replaced.

For more information about testing AFCIs, check out the illustrated How to Test an AFCI fact sheet.

 

What’s the difference between an AFCI and a GFCI?

  • The GFCI is designed to protect people from severe or fatal electric shocks while the AFCI protects against fires caused by arcing faults.

Visit the Ground Fault Circuit Interrupter page for more information about GFCIs.