Home > Articles & Tips > Electrical Safety > What Are Thermal Magnetic Circuit Breakers?
Certified by Truste

What Are Thermal Magnetic Circuit Breakers?

thermal magnetic circuit breaker
Credit: Schneider Electric

Pretty much everyone has experienced an electrical overload in his or her home that tripped the circuit breaker and forced him or her to head to the basement to switch the electrical panel back on. This usually happens when too many appliances plugged are in to one outlet or connected to the same electrical circuit. This is when the circuit breaker kicks in to protect you from potential electrical damage.

The Layman’s Understanding of Circuit Breakers

The purpose of an electrical circuit breaker is pretty much what the name implies: It breaks (or discontinues) a circuit of electricity. It does this automatically when it detects an electrical overload or short circuit in order to prevent damage from occurring. Circuit breakers can then be manually or automatically set to restart the flow of electricity once the potentially dangerous burst of electricity is gone. Circuit breakers come in varying sizes and types and can be used to protect everything from household appliances to high-voltage circuits that service entire cities.

Thermal Magnetic Circuit Breakers

Most homes have something called thermal magnetic circuit breakers. These circuit breakers utilize two techniques to detect electrical faults. The first includes an electromagnet that is sensitive to large surges in electrical currents. Electrical surges can cause short-circuiting, which is bad for all electrical appliances. The electromagnet responds instantly to such dangerous situations by shutting off the flow of electricity so that your appliances are protected. The second technique used in these common household circuit breakers is a thermal bimetallic strip that responds to prolonged low-level electrical surges or overloads of electricalcurrents. Excessive electrical currents will heat the bimetallic strip enough to bend it towards a trip bar that turns the circuit off.

Thermal magnetic circuit breakers are popular because they can quickly limit short circuiting and then restart the flow of electricity when the surge has passed. However, it is important to remember that thermal magnetic circuit breakers are sensitive to temperature, which is important for homeowners in places with extreme temperature changes, like Chicago, and must be set according to the manufacturer’s directions forproper functioning. Additionally, you can limit your own electrical usage to prevent stressing your electrical circuits. Try to keep heavy-consumption electrical devices, such as lamps, heaters, irons and hair dryers, on different circuits and always turn off appliances when they are not in use.


Author Sirena Rubinoff is a writer based in California. She specializes in budget decorating solutions. Ask Sirena how to decorate for less.

Get Up to 4 Free Quotes From Qualified Electricians

Fill in your details and be contacted within minutes

Certified by Truste



Some of our Cities: