NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATIONLow Voltage Distribution Equipment Section

arc faults and

electrical safety

PROTECTING HOMES & FAMILI ES

FROM ELECTRICAL F IRES

WITH ADVANCED TECHNOLOGY

W H AT I S TH E D I F F E R E N C E B E T W E E N AG R O U N D FAU LT A N D A N A RC FAU LT ?

There is a major difference between thefunctioning of an AFCI as compared to a GFCI(Ground Fault Circuit Interrupter). The functionof the GFCI is to protect people from thedeadly effect of electric shock that couldoccur if parts of an electrical appliance or toolbecome energized due to a ground fault. Thefunction of the AFCI is to protect the branchcircuit wiring from dangerous arcing faults thatcould initiate an electrical fire.

AFCI and GFCItechnologies can co-existwith each other and are agreat complement for themost complete protectionthat can be provided on acircuit.

IT ’ S A L L A B O U T S A F E T Y

Smoke alarms, fireextinguishers and escapeladders are all examples ofemergency equipmentused in homes to takeaction when a fire occurs.AFCIs are products designed to detect a widerange of arcing electrical faults to help reducethe electrical system from being an ignitionsource of a fire. Conventional overcurrentprotective devices do not detect low levelhazardous arcing currents that have thepotential to initiate electrical fires.

AFCIs are the next generation product inelectrical circuit protection. As you evaluateyour new home’s construction or considerupgrading or remodeling your currentelectrical system, consider enhancing theprotection of your electrical systemwith AFCI.

NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATIONLow Voltage Distribution Equipment Section

1300 North 17th Street, Suite 1752 • Rosslyn, Virginia 22209(703) 841-3200 Fax: (703) 841-5900

www.nema.org

NEMA AND ELECTRICAL SAFETY

For more than 80 years, manufacturers of lowvoltage distribution equipment have beenworking to ensure public safety by standardswriting efforts and the dissemination ofimportant industry information through theNational Electrical Manufacturers Association(NEMA), one of the most respected standardsdevelopment organizations in the world.

Headquartered in Rosslyn, Virginia, NEMA hasapproximately 400 electroindustry companies,including large, medium and small businesses.To learn more about NEMA visitwww.nema.org.

To learn more about AFCIs, visit our AFCI website at www.afcisafety.org.

ELECTRICAL F IRES KI LLTHOUSANDS EVERY YEAR

According to the U.S. Fire Administration*, homeelectrical problems accounted for an estimated67,800 fires and $868 million inproperty losses in 2003. Electricalfires also cause an estimated 485deaths annually and injure almost2,300 more individuals.

Electrical fires can be caused by anumber of failures. Appliancedefects or misuse, incorrectlyinstalled wiring, or misappliedextension cords can lead to electrical hazards.

In 1992, the Consumer Product SafetyCommission (CPSC) contracted withUnderwriters Laboratories (UL) to provideresearch and evaluation of products andtechnology that could reduce the likelihood ofresidential fires. A result of the research, ULidentified an electrical hazard called “arcingfaults” that could eventually lead to the ignitionof a fire as one possible cause of residential fires.

WHAT IS AN ARC FAULT?

Most people are familiar with theterm arcing. Arcing may beintended, such as with an arcwelder or unintended, such aswhen a tree falls on a power lineduring a storm creating a currentdischarge between conductors orto ground.

An arc fault is an unintended arc created bycurrent flowing through an unplanned path.Arcing creates high intensity heating at thepoint of the arc resulting in burning particlesthat may easily ignite surrounding material,such as wood framing or insulation. Thetemperatures of these arcs can exceed 10,000degrees Fahrenheit.*USFA. 2006. “On the Safety Circuit: A Factsheet on Home ElectricalFire Prevention.” U.S. Fire Administration.

HOW ARE ARCING FAULTS DETECTED?

Traditional overcurrent protective devicescannot detect these types of arcs. Thecapability now exists to detect many of thesearcing conditions and disconnect the problemcircuit through the use of Arc Fault CircuitInterrupters (AFCIs).

HOW DOES AN ARC FAULT CIRCU ITINTERRUPTER (AFC I) WORK?

In essence, the detection is accomplished bythe use of advanced electronic technology to

monitor the circuit forthe presence of“normal” and“dangerous” arcingconditions. Someequipment in thehome, such as amotor driven vacuumcleaner or furnacemotor, naturally create

arcs. This is considered to be a normal arcingcondition. Another normal arcing condition thatcan sometimes be seen is when a light switchis turned off and the opening of the contactscreates an arc.

WHY IS IT IMPORTANT TO HAVE AN AFCIBREAKER INSTALLED IN MY HOME?

AFCIs were developed in response to anidentified electrical problem causing fires in thehome as noted by the Consumer ProductSafety Commission and other prominentorganizations.

An AFCI provides a higher level of protectionthan a standard circuit breaker by detectingand removing the hazardous arcing conditionbefore it becomes a fire hazard.

WHERE ARE THEY REQU IRED TO BEINSTALLED BY THE NATIONALELECTRICAL CODE?

The 2005 National Electrical Code states thatAFCIs must be placed on bedroom power andlighting circuits. The 2008 NECmay expand this requirement toother areas in the home. As withall property protection and lifesaving devices, the ultimate use,beyond the Code, rests with thehomeowner. Whether newconstruction or retrofit, NEMAsupports thatyou utilize themaximumelectricalprotection levelavailable toreduce thechance of anelectrical fire.

CAN I HAVEAFCIsINSTALLED EVEN I F MY STATEOR MUNIC IPALITY DOESN’TREQU IRE THEM?

Absolutely, do you only place locks on the frontdoor of the house? Just like placing locks on allexternal doors and windows for securityreason, it is logical to request AFCI protectionon all 15 and 20A branch circuits, not justthose in the bedroom, to protect the entirehome from an electrical arcing ignition hazard.

AFCIs are available through electricaldistributors and in many home centers andhardware stores nationally. The only majorphysical requirement is that the AFCI requiresdirectly wired hot and neutral wires on thecircuit you’re going to protect.