Homeowners may not give it much thought, but there’s a lot that goes into the process of providing power to your home. Each time you flip a light switch, you’re tapping into a massive and complex power grid.
Transformers near your home reduce high voltage current to the 110-220-volt lines used in homes, while an electric meter records the amount of power drawn into your home. Those are just two of many important components used to keep your lights on and appliances running.
How do circuit breakers work?
Perhaps the most important safety feature in household electrical systems is the circuit breaker, which instantly cuts off power when there is an overload.
In modern homes, a circuit breaker panel (often called the breaker box) can be found in the basement or in a utility closet. Each individual breaker switch inside the box is connected to the wires going to specific rooms of the house. If there is a major energy-using appliance such as an electric water heater, it may have a single breaker switch devoted to it.
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Old-style plug fuses contained a tiny strip of metal so thin it would melt away if too much electricity passed through it. The smaller the fuse amperage rating, the thinner the metal strip. The old screw-in fuses were risky because they were all the same size and homeowners were tempted to put in a stronger fuse than the circuit was designed for.
Modern circuit breaker switches work the same way, except that the switch is not damaged in the process. Instead of buying a new fuse, one only needs to reset the breaker.
How to reset a circuit breaker
Usually, when a breaker shuts itself off, the cause is apparent. Whatever appliance you just turned on before the outage is probably the one that overloaded the circuit.
Appliances can cause a sharp enough amperage spike to trip the breaker. Another common cause, which may be harder to identify, is when the air conditioner kicks on while you have other appliances running on the same circuit.
When the electricity suddenly goes out for only a portion of the house, this nearly always means a circuit breaker has tripped because of a surge in amperage required in the circuit. Before going to the breaker box, first turn off the appliances that were running in the rooms where the power has gone out.
Then take a flashlight and go examine the rows of breakers in the panel. It should be easy to spot the one that tripped because it will be out of line with the other switches. Turn it all the way off, then back on and wait to see if it stays on. If so, head back upstairs to see if the power is back on. Test it by turning the appliances back on.
What you should never do
In the days of screw-in plug fuses, people sometimes would replace a 15-amp with a 20-amp fuse in order to make it less prone to going out. This was a very dangerous practice because in increased the likelihood of an electrical fire. An even more dangerous practice was putting a penny in the fuse opening to bridge the contacts instead of a fuse. This meant the fuse would never go out, but left the house with zero protection against an electrical fire. Many homes burned down because of this.
Today, it’s not so easy to circumvent the purpose of breaker settings. If you have a breaker that repeatedly trips, contact an electrician to diagnose the cause.