“Causes of Residential Electrical Fires”
Residential, electrical fires claim the lives of hundreds of Americans each year and injure thousands more. Some of these fires are caused by electrical appliance defects. The vast majority of them are caused by incorrectly installed wiring, improperly sized wire, fuses, circuit breakers, overloaded circuits, extension cords and loose electrical connections. Each year, home appliance and the above problems account for 50,000+ fires, hundreds of deaths, and upwards of $700 million in property losses. The problems listed above cause twice as many fires as faulty electrical appliances!
Residential electrical fires have many causes, but I’d like to focus on just two here:
1) Loose connections
2) Old/Faulty Circuit Breakers
Loose connections can be the result of time, and wear and tear. For the most part, loose connections are the result of an improper installation. What happens when an electrical connection of any kind is loose? You get an increase in the resistance of the circuit; the increased resistance in that area causes increased power and heat. The increased heat causes the resistance to go up even more, and can also cause oxidization, which causes resistance to go up even more. Eventually, this can lead to a complete open circuit, or to arcing and excessive heat build up which could lead to combustion of the wire insulation and the box that the wires are in. (All of this is happening inside your walls.) Today most residential electrical insulation and boxes are plastic and can catch fire!
The picture (below) shows the result of a combination of a loose connection at one of the main lugs in a sub panel and a faulty main breaker. The loose connection caused the service entrance wire to heat up to the point of combustion. If operating properly, the main circuit breaker would have tripped, removing the current from the wire, allowing it to cool down. Because the main circuit breaker was faulty and did not trip, the wire continued to heat to the point of combustion, which caused the wall that the panel and the wire are mounted on, to catch fire. The entire garage and the bedroom above were burned (luckily, no one was hurt).
Another common mistake made by those who do not have the proper training and experience is to over-tighten wires, especially when installed under screws on electrical devices like “switches” and “receptacles.” This can cause an internal connection to break or weaken which eventually leads to the same issues described above. Below is a picture of what happens when wires are over-tightened under device screws.
This particular receptacle was (and these are my customers words) making “sizzling and popping” noises. The receptacle was installed right behind the headboard of my customer’s bed! The box was also damaged by the fire, and needed to be replaced. What’s important to understand is, that this “little fire” was burning in a wall made of wood studs, and that it could have easily burned down the house. But, due to luck and to the homeowner’s quick action of shutting the circuit breaker off, the fire wasn’t able to burn long enough to ignite inside the wall and cause the house to burn down.
Unless you are 100% confident in your ability to avoid making these mistakes, it’s always best to consult a professional. Electricity and electrical work isn’t something that an untrained or under-trained person should be handling. It’s always best to call a Licensed, Insured and Experienced electrician for any electrical project that you have. The life of those in your home, your life and your property are at stake.