An MCB (Miniature Circuit Breaker) and Bimetal Overload Relays Test Kit, with models Type SI/MCB-100 and SI/MCB-200, is specialized test equipment designed for the calibration and testing of miniature circuit breakers and bimetal overload relays. These components are crucial for the protection of electrical circuits and equipment by detecting overcurrent conditions and disconnecting the circuit when necessary.

Bimetal overload relays test kit and bimetal relays test kit are electro-mechanical protective devices that protect electric motors and transformers from overcurrent and overheating damage. They work by having two metal strips bonded together with different thermal expansion coefficients. When too much current flows through and overheats the relay, the bimetal strips bend and activate a trip mechanism to open the circuit.