The Importance of Circuit Breakers

Posted on 20 December, 2023 by perrilshy

Circuit breakers are a vital safety feature that helps you avoid electrical fires. They help prevent overloading of the system by ensuring that current can't exceed safe levels.

The basic circuit breaker consists of a switch connected to either an electromagnet or bimetallic strip. When the current climbs to unsafe levels, this causes them to heat up and triggers the switch to open.

What is a circuit breaker?

A circuit breaker interrupts current during fault conditions or overload situations preventing extensive damage to electrical equipment. They come in numerous types and sizes for use in residential, utility and large industrial systems.

The breaker senses current through an electro-magnetic trip unit with a coil and piston that are mounted inside the circuit breakers. When load current reaches unsafe levels the voltage on the piston causes it to move against a spool of metal that moves the switch linkage opening the breaker contacts and breaking the circuit. Modern breakers employ microcomputers to monitor each phase at a very high sampling rate. This allows the shape of a breaker's time current curve to be field programmable to meet the desired performance profile. This offers a level of protection never before possible.

How does a circuit breaker work?

If a circuit overloads, shorts or has an arc fault, the molded breakers will trip and shut off power to that part of the system. This stops the current from causing further damage and keeps you and your family safe.

Standard breakers use an electromagnet to sense changes in electrical current. When there is too much current, the electromagnet pulls two metal contact points apart. This opens the switch and shuts off the electricity. More advanced breakers use a bimetallic strip that’s made of two different metals with differing expansion rates when heated. When the current reaches a dangerous level, the bimetallic strip bends, trips the switch and breaks the circuit. These nifty devices are very important to our safety and should be treated with the utmost care and respect. They save people from injuries and fire hazards at home and work. The most basic breakers are also called molded-case breakers and have all the moving parts, mechanisms and switching devices inside a box of insulating material.

What causes a circuit breaker to trip?

Breakers and fuses are designed to trip or blow when they sense four dangerous situations: an overloaded circuit, a short circuit, a ground fault and an arc fault. An overloaded circuit happens when a breaker or fuse attempts to draw a higher electrical amperage load than what it is intended for. When this happens, the internal sensing mechanism heats up and renders the breaker or fuse inactive.

This is a safety feature that protects your home from an electrical fire. If your breaker keeps tripping, it is a sign that you are asking too much of a particular circuit and need to redistribute appliances and devices to other circuits or upgrade your electrical system. Another common cause of a breaker trip is a short circuit, which occurs when an active wire touches a neutral one, creating excessive current and causing the breaker or fuse to shut off power. You may also notice burning smells or see discoloration around outlets when this is the case.