What element causes the circuit breaker to open at a predetermined calibration temperature?

The thermal sensing element is responsible for causing a circuit breaker to open at a predetermined calibration temperature. This element detects the heat generated by the electrical current flowing through the circuit. When the current exceeds a certain level, which indicates a potential overload or fault condition, the thermal sensing element heats up. As it reaches its predetermined calibration temperature, it triggers a mechanism that opens the circuit, interrupting the flow of electricity and preventing damage to the electrical system.

This functioning is crucial for protecting electrical circuits from excessive current that could lead to overheating and potentially result in equipment failure or fire hazards. The precise calibration of the thermal sensing element ensures that the breaker opens only under specific conditions, providing reliable protection while allowing normal operation under less demanding conditions.