LA-Frame Circuit Breaker

There are two different types of technologies that are commonly used in circuit breakers. 

Magnetic Breakers are designed to react to short circuits or sharp spikes in voltage and current. The more current that passes through the breaker’s electromagnet, the stronger the magnet becomes. When the current exceeds the rating for that particular breaker, the magnetic force becomes strong enough that it will pull the contact back and disconnect it from the other contact, disconnecting power from the device.
Thermal Protection Breakers protect against a sustained overcurrent, or a higher current, for a longer period of time. Thermal protection uses a Bimetal strip that will bend the contacts away from each other to disconnect power.

Thermal Magnetic Breakers are the most common type of circuit breakers. They combine magnetic technology to protect against short circuits or sharp spikes and thermal technology that protects against sustained overcurrent for a long period of time.