What protection are circuit breakers mainly used for in circuits

The main protection functions of circuit breakers in circuits include the following two core functions, and other derived functions (such as grounding protection, remote control, etc.) are extended based on these two core functions:

1. Short circuit protection: When a short circuit occurs in the circuit, the circuit breaker quickly cuts off the current through electromagnetic induction or electronic detection mechanism to prevent equipment from burning out or catching fire. The short-circuit current can usually reach tens of times the normal operating current and needs to respond within milliseconds.

2. Overload protection: When the current continues to exceed the rated value (such as line overheating or equipment abnormalities), the circuit breaker will trip after a delay due to thermal or electromagnetic effects to avoid insulation aging or equipment damage.

Other auxiliary protection functions (some circuit breakers may have):

• Grounding protection (detecting leakage or shell electrification)
• Overvoltage and undervoltage protection (cutting off the circuit in case of abnormal voltage)
• Segmented control and remote management (modern intelligent circuit breakers)

Attention: Although the contactor can break the normal load current, it cannot cut off the short-circuit current and needs to be used in conjunction with a circuit breaker.