Miniature circuit breaker or MCB.
It is an Electrical switch designed to protect an electrical circuit from damage caused by (Overcurrent)/(overload) or (short circuit). Its basic function is to interrupt current flow after Protective relays detect faults condition. Unlike a fuse, which operates once and then must ben replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation.
Handling MCB is more electrically safe than fuse.
Because of to many advantages of MCB over fuse units, in modern low voltage electrical network, miniature circuit breaker is mostly used instead of backdated fuse unit.
The disadvantage is that,it's a bit costlier than the fuse or fuse wire.