What is typically the main function of a circuit breaker?

The primary function of a circuit breaker is to protect against overcurrent. This is achieved by interrupting the electrical circuit when it detects a current that exceeds a predetermined limit, which can occur due to faults such as short circuits or overloads. When an overcurrent condition is detected, the circuit breaker automatically opens, breaking the circuit and preventing damage to the electrical system, equipment, and reducing the risk of fire.

By addressing overcurrent conditions promptly, circuit breakers ensure the safety and reliability of electrical systems, hence their critical role in safeguarding electrical infrastructure. This capability differentiates circuit breakers from other components such as fuses, which also provide overcurrent protection but typically do not reset automatically, or devices that regulate current flow, which serve different purposes.