How Does a Circuit Breaker Work?

In this PowerVersity guide, Victor answers the question, “how does a circuit breaker work”?

The guide starts by explaining What a circuit breaker means. It then discusses how a circuit breaker works, and why you need a circuit breaker.

Read through to find all hidden secrets you need to know about a circuit breaker.

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How Does a Circuit Breaker Work?: What is Circuit Breaker?

How Does a Circuit Breaker Work?

To understand how circuit breakers work, you have to understand what electricity means. Electricity is characterized by three main attributes:

  1. Voltage
  2. Current
  3. Resistance

Voltage” is the “pressure” that moves the electrical charge.

Current” is the “flow” of the charge—the rate at which the charge moves through the conductor, measured at any particular point.

A certain degree of “resistance” to this flow is given by the conductor. This varies depending on the composition and size of the conductor.

The fuse box/circuit breaker is a switching device that disrupts the irregular or faults current. It is automatically operated to protect the electrical circuit from been damaged – caused by excess current from an overload or short circuit.

This system is a “must-installed” in electrical flow-linked properties. It is also one of the most critical protection measures to put in place.

The circuit breaker is designed primarily for the closing or opening of an electrical circuit. Therefore protects the electrical system from damage.

How Does a Circuit Breaker Work?: Illustration

circuit breaker testing
Image from shutterstock

Your wife is using her hair blower, your daughter is doing some ironing. At the same time, your son decides to start his Xbox and you also want to have a piece of toast.

You push in the bread, press the handle down, and then the uncommon silence comes. Meaning all the power in your home has come to a complete halt.

You may be wondering what happened?, especially when some part of your house still has electricity flow. Check the beakers!!!

Thus, the need to know the working techniques of a circuit breaker.

How Does Circuit Breaker Work?: The Working Technique

Circuit Breaker Work?
Image courtesy:

To know how a circuit breaker work, you need to understate some electrical facts

Firstly, the circuit breaker consists of fixed and moving contacts. These contacts meet one another and, when the circuit is closed, it retains the current under normal conditions.

When the circuit breaker is closed, the current-carrying contacts, called electrodes, connect with one another. under the pressure of the spring.

For switching and maintenance of the system under normal operating conditions, the arms of the circuit breaker can be opened or closed. Opening the circuit breaker is the only pressure needed to be applied to the trigger.

Be informed that, there is a large current flowing into your building from the power station. Therefore when there is any power circuit, it trips off the circuit breaker.

There are two types of wire bringing current into your building. Thus, the live wire and the neutral wire.

The live circuit / hot wire leads to the power plant while the neutral circuit/neutral wire leads to the ground.

Besides, when wiring any building, since the charge flowing through the circuit passes through an appliance that serves as a resistor, the neutral wire, and hot wire never touch directly.

For this reason, electrical resistance in the appliances limits the amount of charge that can flow through the loop. Appliances are well built to keep current at a relatively fresh, low level, all for safety purposes.

If at some point in time, the charge flow through the loop is too high, the wires of the appliances and the wiring of the building would heat up to an unsafe level. This could probably have caused an outbreak of fire.

Thus, the existence of a circuit breaker prevents such occurrence.

How Does a Circuit Breaker Work?: The Need for a Circuit Breaker

Need for a Circuit Breaker
Image via:

How does a circuit breaker work? What is the purpose of this circuit breaker that cuts off the circuit whenever the current rises above a safe level?. Let us see how.

There is a fuse – a thin wire enclosed in a housing that plugs into the circuit. Electric current flows through the fuse wire when the circuit is closed.

Much like every other point in the circuit, the fuse feels the same amount of current and when it heats up to a certain degree that is dangerous, the fuse disintegrates as designed.

When the currents are too strong, the wire burns up, breaking the fuse and opening the connection until the building’s wire is fried by the excess current.

The basic circuit breaker consists of a simple switch that is connected to either an electromagnet or a bimetallic strip. The hot wire in the circuit connects to the two ends of the switch. As soon as the switch is being flipped to the ON position, electricity can flow from the bottom through the electromagnet, up to the moving contact across to the stationary contact, and out to the upper terminal

I hope you found this PowerVersity guide on how does a circuit breaker work helpful?

If you found it helpful, kindly share your thoughts with the “Leave a Reply” form found towards the end of this page.

Finally, to read more guides like this, visit our Electrical Accessories page

Victor Akin-Ojo
Victor Akin-Ojo is the founder and the Lead Editor of Before he started, Victor worked in the IT industry for close to 15 years. He worked mainly as field Engineer on Installation of VSAT, Wimax Technologies, including but not limited to, Power Maintenance Sector for close to 10 years – Designing an electrical installation for Homes, Private and Government Offices and more.
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