Miniature Circuit Breaker

A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by excess current from an overload or short circuit. Its basic function is to interrupt current flow after a fault is detected. Unlike a fuse, which operates once and then must be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation. A miniature circuit breaker (MCB) automatically switches off the electrical circuit during abnormal network conditions, such as overload or fault conditions. Nowadays, we use MCBs in low-voltage electrical networks instead of fuses. A fuse may not detect such issues, but a miniature circuit breaker does so in a more reliable manner. MCBs are much more sensitive to overcurrent than fuses. Handling an MCB is electrically safer than handling a fuse. While restoring power after a fuse trip requires rewiring or replacing the fuse, power can be easily restored with an MCB by simply switching it back on. How does a miniature circuit breaker work? The Working Principle of MCB Whenever continuous overcurrent flows through an MCB, the bimetallic strip heats up and deflects by bending. This deflection releases a mechanical latch, which is connected to the operating mechanism, causing the MCB contacts to open. The MCB then turns off, stopping current flow in the circuit. To restart the current flow, the MCB must be manually turned on. This mechanism protects against faults caused by overcurrent or overload. During a short circuit, however, the current rises suddenly, causing electromechanical displacement of a plunger associated with a tripping coil or solenoid. The plunger strikes the trip lever, immediately releasing the latch mechanism and opening the circuit breaker contacts. This is a simple explanation of how a miniature circuit breaker works. An MCB is very simple, easy to use, and generally not repaired—instead, it is easier to replace. The trip unit is the main component responsible for its proper operation, with two main types of trip mechanisms: a bimetal strip provides protection against overload current, and an electromagnet provides protection against short-circuit current.If you have related product needs, please contact us at any time!
E-mail: sales@zcebox.com