Arc Fault Circuit Interrupter
(AFCI)
FACT SHEET
THE AFCI
The “AFCI” is an arc fault circuit
interrupter. AFCIs are newly-developed
electrical devices designed to protect
against fires caused by arcing faults in the
home electrical wiring.
THE FIRE PROBLEM
Annually, over 40,000 fires are attributed
to home electrical wiring. These fires
result in over 350 deaths and over 1,400
injuries each year(1). Arcing faults are one
of the major causes of these fires. When
unwanted arcing occurs, it generates high
temperatures that can ignite nearby
combustibles such as wood, paper, and
carpets.
Arcing faults often occur in damaged or
deteriorated wires and cords. Some causes
of damaged and deteriorated wiring include
puncturing of wire insulation from picture
hanging or cable staples, poorly installed
outlets or switches, cords caught in doors
or under furniture, furniture pushed against
plugs in an outlet, natural aging, and cord
exposure to heat vents and sunlight.
HOW THE AFCI WORKS
Conventional circuit breakers only respond to overloads and short circuits; so they do not
protect against arcing conditions that produce erratic current flow. An AFCI is selective
so that normal arcs do not cause it to trip.
The AFCI circuitry continuously monitors current flow through the AFCI. AFCIs use
unique current sensing circuitry to discriminate between normal and unwanted arcing
conditions. Once an unwanted arcing condition is detected, the control circuitry in the

AFCI trips the internal contacts, thus de-energizing the circuit and reducing the potential
for a fire to occur. An AFCI should not trip during normal arcing conditions, which can
occur when a switch is opened or a plug is pulled from a receptacle.
Presently, AFCIs are designed into conventional circuit breakers combining traditional
overload and short-circuit protection with arc fault protection. AFCI circuit breakers
(AFCIs) have a test button and look similar to ground fault circuit interrupter (GFCI)
circuit breakers. Some designs combine GFCI and AFCI protection. Additional AFCI
design configurations are anticipated in the near future.
It is important to note that AFCIs are designed to mitigate the effects of arcing faults but
cannot eliminate them completely. In some cases, the initial arc may cause ignition prior
to detection and circuit interruption by the AFCI.
The AFCI circuit breaker serves a dual purpose – not only will it shut off electricity in the
event of an “arcing fault”, but it will also trip when a short circuit or an overload occurs.
The AFCI circuit breaker provides protection for the branch circuit wiring and limited
protection for power cords and extension cords. Single-pole, 15- and 20- ampere AFCI
circuit breakers are presently available.
WHERE AFCIs SHOULD BE USED
The 1999 edition of the National Electrical Code, the model code for electrical wiring
adopted by many local jurisdictions, requires AFCIs for receptacle outlets in bedrooms,
effective January 1, 2002. Although the requirement is limited to only certain circuits in
new residential construction, AFCIs should be considered for added protection in other
circuits and for existing homes as well. Older homes with aging and deteriorating wiring
systems can especially benefit from the added protection of AFCIs. AFCIs should also
be considered whenever adding or upgrading a panel box while using existing branch
circuit conductors.
INSTALLING AFCIs
AFCI circuit breakers should be installed by a qualified electrician. The installer should
follow the instructions accompanying the device and the panel box.
In homes equipped with conventional circuit breakers rather than fuses, an AFCI circuit
breaker may be installed in the panel box in place of the conventional circuit breaker to
add arc protection to a branch circuit. Homes with fuses are limited to receptacle or
portable-type AFCIs, which are expected to be available in the near future, or AFCI
circuit breakers can be added in separate panel boxes next to the fuse panel box.
TESTING AN AFCI
AFCIs should be tested after installation to make sure they are working properly and
protecting the circuit. Subsequently, AFCIs should be tested once a month to make sure
they are working properly and providing protection from fires initiated by arcing faults.
A test button is located on the front of the device. The user should follow the instructions
accompanying the device. If the device does not trip when tested, the AFCI is defective
and should be replaced.
AFCIs vs. GFCIs
The AFCI should not be confused with the GFCI or ground fault circuit interrupter. The
GFCI is designed to protect people from severe or fatal electric shocks while the AFCI
protects against fires caused by arcing faults. The GFCI also can protect against some
electrical fires by detecting arcing and other faults to ground but cannot detect hazardous
across-the-line arcing faults that can cause fires.
A ground fault is an unintentional electric path diverting current to ground. Ground
faults occur when current leaks from a circuit. How the current leaks is very important.
If a person’s body provides a path to ground for this leakage, the person could be injured,
burned, severely shocked, or electrocuted.
The National Electrical Code requires GFCI protection for receptacles located outdoors;
in bathrooms, garages, kitchens, crawl spaces and unfinished basements; and at certain
locations such as near swimming pools. A combination AFCI and GFCI can be used to
satisfy the NEC requirement for GFCI protection only if specifically marked as a
combination device.

1 Ault, Singh, and Smith, “1996 Residential Fire Loss Estimates”, October 1998, U.S. Consumer
Product Safety Commission, Directorate for Epidemiology and Health Sciences.

Arc Fault Breakers

Did you know that many fires result when wires or electrical products are damaged, improperly used, or old? And did you know that traditional circuit breakers and fuses may not detect these problems?

Arc fault circuit interrupters are designed to detect arc faults, as well as the more traditional overloads, short circuits and ground faults.

You may want to consider using these new arc fault breakers. Traditional circuit breakers and fuses won't stop electric shock or electrocution if an accident happens - they just don't work fast enough. Unfortunately, the current needed to severely shock or kill a person is MUCH LOWER than the current needed to trip a breaker. Additionally, traditional breakers might not trip if arcing occurs. Arc faults can also result from every-day common occurrences - such as hanging a new picture or screwing a cabinet into the wall and accidentally puncturing the wire insulation.

The arc fault circuit interrupter reduces the possibility of both a fire in your home started by faulty wiring connections, cords, appliances and other hazards, and accidental electrocution. It contains a microprocessor that is programmed to recognize the characteristics of arc faults. It then shuts off the power supply until the current flow is normal again.

With arc fault breakers, you've got added security for you and your family. Just check out what can happen when fuse boxes and the neighborhood handyman get together.

To find out how affordable it is to install arc fault breakers in your house ), email us at info@brownelectricinc.com

A Factsheet on Home Electrical Fire Prevention

Electrical fires in our homes claim the lives of 485 Americans each year and injure 2,305 more. Some of these fires are caused by electrical system failures and appliance defects, but many more are caused by the misuse and poor maintenance of electrical appliances, incorrectly installed wiring, and overloaded circuits and extension cords.

The United States Fire Administration (USFA) would like consumers to know that there are simple steps you can take to prevent the loss of life and property resulting from electrical fires.

THE PROBLEM

During a typical year, home electrical problems account for 67,800 fires, 485 deaths, and $868 million in property losses. Home electrical wiring causes twice as many fires as electrical appliances.

THE FACTS

December is the most dangerous month for electrical fires. Fire deaths are highest in winter months which call for more indoor activities and increase in lighting, heating, and appliance use. Most electrical wiring fires start in the bedroom.

THE CAUSE

Electrical Wiring

• Most electrical fires result from problems with "fixed wiring" such as faulty electrical outlets and old wiring. Problems with cords and plugs, such as extension and appliance cords, also cause many home electrical fires.
• In urban areas, faulty wiring accounts for 33% of residential electrical fires.
• Many avoidable electrical fires can be traced to misuse of electric cords, such as overloading circuits, poor maintenance and running the cords under rugs or in high traffic areas.

Home Appliances

• The home appliances most often involved in electrical fires are electric stoves and ovens, dryers, central heating units, televisions, radios and record players.

SAFETY PRECAUTIONS

• Routinely check your electrical appliances and wiring.
• Frayed wires can cause fires. Replace all worn, old or damaged appliance cords immediately.
• Use electrical extension cords wisely and don't overload them.
• Keep electrical appliances away from wet floors and counters; pay special care to electrical appliances in the bathroom and kitchen.
• When buying electrical appliances look for products which meet the Underwriter's Laboratory (UL) standard for safety.
• Don't allow children to play with or around electrical appliances like space heaters, irons and hair dryers.
• Keep clothes, curtains and other potentially combustible items at least three feet from all heaters.
• If an appliance has a three-prong plug, use it only in a three-slot outlet. Never force it to fit into a two-slot outlet or extension cord.
• Never overload extension cords or wall sockets. Immediately shut off, then professionally replace, light switches that are hot to the touch and lights that flicker. Use safety closures to "child-proof" electrical outlets.
• Check your electrical tools regularly for signs of wear. If the cords are frayed or cracked, replace them. Replace any tool if it causes even small electrical shocks, overheats, shorts out or gives off smoke or sparks.

Finally, having a working smoke alarm dramatically increases your chances of surviving a fire. And remember to practice a home escape plan frequently with your family.