DO NOT CAUSE ELECTRIC FIRES THIS COLD SEASON BY OVERLOADING YOUR ELECTRIC CIRCUIT
During
cold weather we get the highest number of electric fires. These fires are not only damaging
property-wise, but they are taking lives, as well. Faulty wiring or electrical sockets overloaded
by heating devices can and will spark. Space
heaters can also ignite. Check to see if
your appliance has a “tip switch,” meaning it turns off automatically if tipped
over. Remember to set space heaters on a
solid, level surface that is not carpeted to insure that it does not tip over
and also to insure that the tip over switch can function. Never drape blankets or place combustible
items near space heaters and keep a minimum of three (3) foot distance from the
heating unit.
If
your home loses power, do not use a gas kitchen oven to heat your home. This isn’t just a fire hazard – it can produce
toxic fumes, too. Be safe and cautious
when using candles or open flames for light or warmth, and never place them in
areas where they could be knocked over or near items that may easily catch
fire.
Portable
heaters can keep us warm and increase our comfort, but they can also be
dangerous. More than 40,000 residential
fires, and over 300 deaths are associated with the use of portable space
heaters every year. (Source: U.S. Consumer Product Safety Commission and
NFPA). As electrical fire
investigators, one of our jobs is to repair wiring in homes and businesses that
have been damaged. In many instances in
the winter months we find wiring that has been damaged by overloading it with
portable heaters. Most homes have
electrical wiring for outlets and lights that is rated for 15 amps of electric
current. A standard 15 amp, 120 Volt general
circuit will have a combination of 10 to 20 lights and outlets which will serve
TVs, VCRs, lights, computers, exhaust fans and similar items. A typical portable heater uses 1,500 watts or
12.5 amps (the heater nameplate has this information). When you connect a
portable heater rated at 12.5 amps to a circuit that is designed to handle 15
amps maximum, the problem is easy to see. You can easily overload the typical electrical
wiring in your home if a few lights, TVs, computers or other electrical
appliances are turned on at the same time that you are running a portable
heater.
What is an Arc Fault?
Many times the
culprit is an arc fault. An arc is a
discharge of electric current across a gap. Many of us have seen an arc such as from an
arc welder or sparks from a downed power line. An arc fault is an unintended arc flowing
through an unintentional path.
Common causes for arc faults in a house
are:
- Loose or improper connections, such as electrical wires to outlets or switches
- Frayed or ruptured appliance or extension cords.
- Pinched or pierced wire insulation, such as a wire inside a wall nipped by a nail or screw or a chair leg setting on an extension cord.
- Cracked wire insulation stemming from age, heat, corrosion or bending stress
- Overheated wire or cords due to overloading of the circuit
- Damaged electrical appliances
- Wires or cords touching vibrating metal
- Electrical wire insulation chewed by rodents.
When an arc fault
occurs inside the walls or ceiling, or inside an electrical appliance, temperatures
can exceed 10,000 degrees Fahrenheit. Nearby combustibles like wood studs or
insulation can be ignited by an electrical arc.
Fortunately,
companies have developed arc fault circuit interrupters (AFCI) to help avoid
fires caused by arc faults. They look
and work just like conventional circuit breakers and fit into electrical panels
in the same way. But they provide additional protection against arc faults.
Conventional circuit
breakers “trip” if an overload or short circuit is detected, which shuts off
the electrical power. They protect against overloads and short circuits with
thermal and magnetic protection, respectively. AFCI’s, however, not only protect against
overloads and short circuits, they can also electronically sense arcing and
“trip.”
Metropolitan Engineering, Consulting &
Forensics (MECF)
Providing Competent, Expert and Objective Investigative Engineering and
Consulting Services
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E-mail: metroforensics@gmail.com
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