How Does a Circuit Breaker Work? What You Absolutely Must Know

Chances are, you know what a circuit breaker is.

But how does a circuit breaker work?

If you’re unsure, it’s time to change that.


Because circuit breakers are essential to your home or operation’s building.

The 4 Main Components of Your Circuit Breaker

Once you understand how a circuit breaker works, you’ll have a much easier time diagnosing problems when they occur.

Here are the four main components of your breaker.

1. The Fuse

The fuse is the simplest form of protection for your circuit. However, despite this simplicity, it is central to how a circuit breaker works.

It’s just a thin wire enclosed in a casing that connects to your circuit. As long as the circuit stays closed, charges will only typically flow within the fuse. And when it heats up, it’s basically designed to disintegrate once the temperature gets to a certain point. The wire will literally burn up. That’s what happens when you’ve “blown a fuse.”

The reason it’s designed to do this is so that the circuit will open before the excessive current is able to damage the house or building’s wiring.

2. The Switch

The switch of your circuit breaker is connected to either an electromagnet or a bimetallic strip. Its two ends also connect to the wire.

When the switch is switched on, electricity flows from the bottom of the terminal up the moving contact through the electromagnet. Then it goes from the stationary contact to the upper terminal.

3. The Electromagnet and Bimetallic Strip

Increasing amounts of current increases the electromagnet’s force. Decreasing it does the opposite.

If the current reaches unsafe levels, the electromagnet’s magnetic force will become strong enough to actually pull the magnetic lever that’s connected to the switch linkage. This will result in the contact moving away from the stationary contact and, thus, breaking the circuit and shutting the electricity off.

Circuit breakers that have bimetallic strips instead of electromagnets rely on the same principle. The main difference is that the current becomes strong enough to bend the linkage, not energize an electromagnet.

Some breakers even utilize an explosive charge to activate the switch. The explosive material pushes a piston which opens the switch.

4. The Ground Fault Circuit Interrupter (GFCI)

More advanced circuit breakers use ground-fault circuit interrupters (GFCI), which protect people from getting shocked as opposed to the other components of a circuit breaker. These are designed to protect the home and building.

GFCIs constantly monitor the current in a circuit’s hot and neutral wires.

Usually, the currents in each should be exactly the same.

However, if someone were to accidentally touch it, for example, that would connect it to the ground, causing a surge. As the neutral wire wouldn’t experience the same surge, the GFCI would notice the difference and break the circuit right away to prevent electrocution.

The advantage with a GFCI is that it doesn’t need to wait until the electricity levels become unsafe before it steps in, unlike a conventional breaker.

How Does a Circuit Breaker Work?

Now That You Understand How a Circuit Breaker Works

Again, the point of this article isn’t to make you think it’s a good idea to grab your tools the next time your breaker is giving you problems.

However, at least now, you’ll understand what the problem is and whether or not you need to spend money on an electrician.

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