Electrical fires are pervasive throughout the United States, causing injury, claiming lives
Electricity can have dangerous consequences. Electrical fires are pervasive throughout the United States, causing injury, claiming lives, and resulting in large losses of property. Faulty electrical systems cause many fires. Even more electrical fires result from inappropriate wiring installations, overloaded circuits, and extension cords. Based on the latest available data for 2003 to 2005, an estimated 28,300 residential building electrical fires occur annually and cause 360 deaths, 1,000 injuries, and losses of $995 million.1,2,3 Electrical fires accounted for 7% of all residential building fires in this 3-year period.
Electrical fires are not always noted as such. When fire is severe, it can be difficult, for example, to discern whether an electric appliance started the fire or if a poorly wired plug was the cause. Heat-producing electrical equipment (e.g., hair dryers, portable heaters, cooking appliances, and the like) tend to use more power than other electrical equipment. Devices like these may overload a circuit, especially one that is already reaching its maximum amperage allowance. Coupled with a faulty circuit breaker, this overload can cause the products to overheat and possibly to catch fire. Moreover, electrical fires that start in walls can smolder for some time. By the time the fire is detected, most likely it already has spread within the walls, unseen. There are over three times more residential building electrical fires than nonresidential building electrical fires, so the problem is particularly important for each of us in our homes.
The fire can cause electrocution
Electrical fires can be particularly tricky to put out. Since they involve electricity, and water conducts electricity, using water to put out the fire can cause electrocution. Chemical powders can cause the fire to smolder rather than extinguish, setting the stage to reignite. Turning power off to the residence is an important step, if it is possible to do so. While new construction is not immune from electrical fires caused by faulty wiring, there are many older homes with outdated wiring that is deteriorating, inappropriately amended, or insufficient for the electrical loads of a typical household in the 21st Century.
Overloaded wiring and circuitry
According to Underwriters Laboratories (UL), over 30 million homes--more than one-third of all U.S. housing--are more than 50 years old. Consider the expansion in the number of appliances used by residents in the past half-century, and it is quickly obvious that overloaded wiring and circuitry is likely in these structures. Overloading will heat up wiring that already could be deteriorating, crumbling, and no longer a good insulator. Just how big this problem is remains to be seen. The Residential Electrical System Aging Research project was launched by the Fire Protection Research Foundation to study how the age of wiring, outlets, junctions, and other connectors affects the pattern of electrical fires in homes.5,6 One objective of the study is to make improvements to the National Electrical Code(R) (NEC) (National Fire Protection Association (NFPA) 70) and through the building codes adopted by local and State jurisdictions around the country.
What these consumers really do is create unseen hazards in their homes. Inside the walls, wiring is heating and damaging its own insulation, wood frames are being charred by high-wattage light bulbs too close to ceilings, and fixture wattage ratings are being exceeded. But as long as the lights come on and the appliances start, the consumer remains unaware of the danger--until a fire starts. They meet their needs by adding more circuitry (and circuit breakers in blank spots on the breaker panel, or even another circuit breaker box) and outlets to accommodate their purchases. If an outlet is added to an existing circuit, then the load easily can be more than the wiring originally was designed to conduct--perhaps decades ago
Fifteen percent of residential building electrical fires start in a bedroom
The functional and structural areas of the home are the most likely to experience electrical fires. Included in the functional category are bedrooms, dining rooms, kitchens, bathrooms, laundry areas, and the like. Fifteen percent of residential building electrical fires start in a bedroom .The bedroom also is the leading area of fire origin for fires with injuries and dollar loss--bedrooms account for 30% of residential building electrical fires that result in injuries and 16% of residential building electrical fires that result in dollar loss. Structural areas of the home include areas such as crawl spaces, attics, walls, porches, and roofs. Attics, the second leading area of fire origin, account for 11% of residential building electrical fires. Over a quarter of all residential electrical fires start in these two areas. While fewer residential electrical fires start in lounge areas (family rooms, living rooms, and the like), these fires result in nearly a third of the deaths (31%).
Electrical wires and structural member/framing account for 38% of all deaths from fires
By far, building structural components is the largest category of items first ignited in residential building electrical fires Structural components include structural member or framing, insulation, trim, wall coverings, flooring, and the like. Of these components, structural framing (usually wood) accounts for 17% of residential electrical fires Insulation and interior and exterior wall coverings (e.g., paneling, wallpaper, siding) account for an additional 18% of residential electrical fires. However, the leading item first ignited in residential electrical fires is the insulation around electrical wires and cables. At 30% of residential electrical fires, it accounts for nearly the entire general materials category. Together, insulation around electrical wires and structural member/framing account for 38% of all deaths from fires in residential buildings When Residential Building Electrical Fires Occur
The occurrence of indoor fires stemming from electrical problems
Heating, lighting, and cooking activities are highest in winter and so, too, are the occurrence of indoor fires stemming from electrical problems. Throughout most of the year, the pattern of residential electrical fires is consistent, but occurrences peak in December and January, accounting for 22% of all such fires (Figure 3). In the winter months, the relative humidity within the walls of a typical home can be very, very low and can turn wood wall framing into kindling, easily ignited by an arcing current. Fire deaths also are high in these months, but March and October, still dry months, both have similar peaks. Summertime has the lowest incidence of deaths resulting from electrical fires in the home. late afternoon and evening are the most likely time for electrical fires to occur in residences. But it is the hours before dawn, between 3 and 6 in the morning, when deaths are most frequent.
Equipment Involved in Residential Building Electrical Fires
Wiring and electrical components have a life expectancy that does not always equal the life cycle of the building. As the electrical equipment wear out, fires are more probable. Electrical wiring with its various components is by far the major culprit in residential building electrical fires. Lamps and other lighting and cords and plugs also present severe problems
Most residential building fires are confined to the object of origin (62%) with 38% of fires spreading through the residence and beyond (Figure 6). Fire spread from residential building electrical fires, however, has nearly the opposite profile--these electrical fires are more likely to spread throughout the home. Sixty-five percent of residential building electrical fires spread beyond the initial object that started the fire. Structural members and framing contribute most to flame spread (27%).
The source of an electrical fire can be hard to determine
the source of an electrical fire can be hard to determine, some known culprits--overloading circuits with heat producing equipment, for example--can lead to items such as the insulation around electrical wires and cables catching fire, either slowly or immediately. With over three times more residential building electrical fires than nonresidential building electrical fires, it is important to ensure that the electrical panels, outlets, switches, and junction boxes in your home are correctly installed and not damaged or modified by unlicensed electricians. Do not use extension cords and multiple plug-in devices as a replacement for new circuits. Since 15% of residential building electrical fires start in a bedroom, upgrade bedrooms with AFIs where possible.