You could probably guess at a lot of the causes of home electrical fires. Placing flammable materials like paper on top of hot lightbulbs, allowing cords to become dangerously frayed, or overloading outlets with tons of appliances are all potential hazards. But there's one cause that fewer people know about: arc faults.
What Is An Arc Fault?
Arcs of electricity aren't always created unintentionally. If you've ever watched someone weld metal with an arc welder, you've seen how useful electrical arcs can be – and also how much heat they can create. By passing electricity through the air in an arc, a controlled source of heat is created that is even used in smelting furnaces to create steel. And some electric motors create small arcs within them as they run.
Arc faults, on the other hand, happen when electricity arcs through the air unintentionally. This happens when a circuit is interrupted but lack of insulation allows the electricity to jump between the interrupted parts of the circuit through the air. Frayed cords are one possible example of this. When the insulation is worn through and the wiring beneath is damaged, electricity can jump past the damaged part of the wiring in a hot arc.
Where Do Arc Faults Happen In The Home?
Frayed cords are one possible place. But because frayed cords are visible, you're more likely to have them fixed before an arc fault occurs. The most dangerous places for arc faults are those that are out of sight. Wall wiring is one possibility; nails or screws that pierce wiring in the walls can compromise the circuit and cause arcing. Wiring is often stapled to studs inside the walls; improper stapling, with staples piercing the wiring, is another hidden possibility.
What Can You Do About Arc Faults?
While prevention is important – keeping your wiring in good shape and not installing nails or screws into the wall right next to light fixtures or electrical outlets – the fact that so much of your wiring is hidden means that detection is also key. And while ordinary circuit breakers don't detect arc faults, there's a type that does: an arc fault current interrupter, or AFCI.
AFCIs work by monitoring the shape of the electrical current running through your circuits. If they detect an abnormal shape, they are tripped and the current is shut off before the arc can cause too much heat. In this way, installing an AFCI protects your home from a hidden source of electrical fires.
It's important to note that installing AFCI circuit breakers is dangerous work and should only be done by a trained electrician. The installation means working on circuits with live current, which means the possibility of shock or electrocution. If you're interested in having an AFCI for your home, contact a residential electrician.