How a Power Circuit Breaker Works

With increased usage of electrical devices, some homeowners are depending more than ever on circuit breakers they can reset after these breakers trip. However, you might not understand circuit breakers and therefore become frustrated with not knowing how to restore power that has been interrupted by overloaded circuits. Here are 4 things you should know about power circuit breakers and how they work

1 - Why Circuit Breakers Shut Off

Typically, circuit breakers shut off because circuits become overheated. How? Copper wire, which conducts electricity throughout the house, sometimes heats up because there is too much electrical current flowing through it. Without some way to reduce a current that is overheating, the copper wire can increase in heat and can start a fire. The safety device that stops this overheating is the circuit breaker.

2 - How a Circuit Breaker Shuts Off Electricity

All electricity flows through a circuit breaker when it first enters the house from the street. When the circuit breaker senses excessive heat in the circuit, the circuit breaker opens, stopping the flow of electricity and resulting heat.

3 - How a Circuit is Restored After It has Been Interrupted

When your electrical power goes off, you can usually tell if it is only a single circuit that has shut down. If other appliances or lights in the house are still working, you can safely assume only one circuit was interrupted. To restore power, find the cause of the disruption and disconnect power from the device. Then, locate your breaker panel and the switch that automatically turned off. Flip this switch back on. If you disconnected the device that caused the disruption, your breaker switch should stay on.

4 - Types of Circuit Breakers

Circuit breakers, though they are not all alike, all perform the same function. They open a circuit that stops the flow of electricity through a copper wire circuit. Differences in circuit breakers are in how they disrupt the circuit they are designed to protect. The three most common type of circuit breakers are:

• Fuse Box - an electric current runs through a filament that is heated by an overloaded circuit, disintegrating the filament and interrupting the flow of electricity. The disadvantage to this type of circuit breaker is that the fuse must be replaced, rather than reset, as other circuit breakers are.
• Magnetic Circuit Breakers - an electric current passes through a coil near a magnet-operated switch. By passing through the coil the current creates a magnetic field which then pulls the switch magnet, closing the switch when the current increases past a safe level.
• Bimetallic Circuit Breakers - a bimetallic strip, consisting of two strips of different metals, expands when a current flows through it. When the current increases, the degree of the strips bend increases until it trips a switch

You can restore power by resetting tripprf bimetallic and magnetic circuit breakers, but first be sure you have disconnected the device that tripped the circuit. With this understanding of circuit breakers you should now know how to reset—or replace—your home's circuit breakers