Miniature Circuit Breaker Introduction:- MCB (Miniature Circuit Breaker) is mechanical device operate automatic operation designed to connect and disconnect the electrical circuit in the ordinary and extraordinary situation . Suitable for AC and DC voltage. It means main function is to protected equipment Or circuit from over load and short circuit. The size OF MCB is small and usually use for household and domestic. Average fix ampere rating from 6 Amp up to 125 Amp. It can be reset back to the normal condition after trip but cannot adjust ampere rating. It can be found for single phase and three phase Voltage power supply. Parts of Miniature Circuit Breaker : (1) Actuator piker (for trip and reset) (2) Actuator Device mechanism (3) Main contact (flow of current) (4) Terminal Block (5) Bimetallic steel strip (6) Tripping calibration screw (7) Solenoid coil (8)Arc extinguisher Purpose: Miniature Circuit Breakers or MCB are used to replace fuses that pro -tect individua