Prevent Home Electrical Fires
By: Monte Burch

Electrical problems are the cause of more than 40,000 home fires in the United States
each year. On average, these fires claim close to 350 lives, injure 1,400 and result in
$700 million in damages according to the U.S. Consumer Product Safety Commission.  
Arc faults, or electric arcs, are one of the main culprits.  Arc faults can be caused by
broken wires, deteriorated insulation or even by driving a nail into a wire.  A plasma flame
that can reach temperatures as high as 9,000 degrees Fahrenheit characterizes these
arcs.  An arcing fault can go undetected by standard, present-day residential circuit
breakers and fuses, which are designed to detect short circuits that can cause an
electricity surge.

Arc Fault Circuit Interrupters (AFCIs) are designed to provide better protection from arc
fault fires.  Typical household fuses and circuits do not respond to early arcing and
sparking conditions in home wiring.  By the time a fuse or circuit breaker opens a circuit
to defuse these conditions, a fire may already have begun.  Several years ago, a
Consumer Product Safety Commission study identified arc fault detection as a promising
new technology.  Since then, CPSC electrical engineers have tested the new AFCIs on
the market and found these products to be effective in protecting homes from certain
faulty wiring conditions.  AFCIs are already recognized for their effectiveness in
preventing fires.  The most recent edition of the National Electrical Code, the
widely-adopted model code for electrical wiring, requires AFCIs for bedroom circuits in
new residential construction.  Future editions of the code will most likely expand
coverage. The bedroom circuit code was adopted because many home fire fatalities
occur when residents are trapped in bedrooms. You may want to consider adding AFCI
protection for either new or older existing homes.  Older homes with ordinary circuit
breakers may especially benefit from the added protection against the arcing faults that
can occur in older wiring systems.

AFCI Applications
Branch circuit AFCIs may be circuit-breaker type, or may be separate units in their own
enclosure, mounted near the panel board.  A branch feeder is installed in the panel
board at the origin of the branch circuit.  These protect the branch circuit wiring, feeder
wiring and also provide some limited protection to branch extension wiring, such as cord
sets or power supply cords.

Outlet circuit AFCIs are installed at the branch circuit outlet box and provide protection for
cord sets and power-supply cords that are plugged into the outlet box.  Combination
devices comply with the requirements for both branch/feeder and outlet circuits and, they
provide protection for downstream branch circuit wiring as well as cord sets and power-
supply cords.

Outlet/branch circuit units are installed at the first outlet in a branch circuit.  They provide
protection to downstream branch wiring, cord sets and power-supply cords as well as
upstream branch circuit wiring.  Portable units plug into a receptacle outlet. These units
provide protection to connected cord sets and power-supply cords.  Damaged or
overheated supply cords often cause fires, and these simple units can be a lifesaver.

Corded AFCIs are often part of a power-supply cord and are designed to plug into a
receptacle to provide protection to the power cord.

A similar device is the Leakage-Current Detection and Interruption device (LCDI). This is
provided in a cord set or power supply cord and senses the current flowing through the
cord.  It interrupts the circuit at a preset current leakage level.  It's important to
understand that none of the above devices are the same as Ground Fault Circuit
Interrupters (GFCIs).  GFCIs are designed to provide protection against electrical shock.
Combination devices that include both AFCI and GFCI protection in one unit will be
available soon.  As an example of what is available, FIRE-GUARD AFCI circuit breakers,
from Eaton/Cutler-Hammer, can be applied to all residential, commercial and industrial 15
and 20 ampere, 120/240V AC applications.  They must use a loadcenter approved for
use with Cutler-Hammer type CH or BR circuit breakers.  FIRE-GUARD AFCIs are
available in both single-pole and two-pole types.  They can also be used in conjunction
with a downstream GFCI device, such as a receptacle or ground-fault relay.  Siemens
manufactures a branch/feeder arc fault circuit interrupter that incorporates all of the
features of a thermal magnetic circuit breaker, overload and short circuit protection, with
arc fault protection.  Siemens AFCIs employ electronic circuitry to continuously monitor
the circuit and determine the unique characteristics of arcing faults.  When there is an
instance of arc fault the AFCI opens the circuit and stops the flow of electricity in a
fraction of a second.  Some connected loads, such as motors and dimmer switches, have
inherent arcing as a normal mode of operation, but the Siemens AFCI is designed to
distinguish these arcing faults from hazardous faults.

For more information on AFCIs contact an electrical supply store, an electrician or the
manufacturer of circuit breakers already installed in your home.  Sometimes these
components can be replaced with AFCIs in the existing electrical panel box.  
Unless you
have experience with electrical work, have a qualified electrician install AFCIs;
do not attempt to do this job yourself.
 The installation sometimes involves working
within electrical panel boxes that can be
electrically live, even if the main circuit breaker
is turned off.  If you are qualified to do the job, it's relatively simple.  Determine the
breaker that is to be replaced.  Turn off the power with the main circuit breaker, which is
located at the top center of the main panel.  Remember, power is still coming into the
panel at the main breaker.  Remove the old breaker by grasping the end where the
branch wires are connected and pulling outward from the buss.  Loosen the screws
holding the branch wires in the old breaker, and pull the wires out.  Install the branch
wires into the appropriate screw holes of the AFCI circuit breaker, and tighten the screws.
Position the new breaker into the buss slot with the screw terminal end facing outward
from the center of the buss.  Press the inside edge in place, then push the breaker
toward the center of the panel buss, and press in to engage it in place.  Fasten the panel
neutral or pigtail to the panel neutral or load center.  Finally, turn on the main breaker
and close the panel door.  AFCIs branch feed or circuit breaker replacement units cost
about $25 to $35.  Regardless the age of your home, you can provide greater electrical
fire protection with the use of these new home products. They're very economical
insurance.
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Arc Fault Circuit
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