As a kind of over current protection device, miniature circuit breakers can be used to switching indoor wiring with current control switching, can effectively protect the important components of the electrical, mainly used for short circuit protection and prevent serious overloading, motor load protection on industrial machines will also specify the use of miniature circuit breakers is one of the protective device.

When the handle is pulled up by hand, the starting current will be executed. When the circuit is overloaded or short circuited, it will automatically jump off. After the cause of the accident has been removed, it will be pulled down again and pulled up again, otherwise the closed circuit can not be reached again.

Different from ordinary power switching, spring and arc suppression device are added for miniature circuit breakers. In the spring break or closed in the process of operation, pre storage spring force to the critical point, the moment bounce off and fast on or off contact, so the operation speed is not affected by the speed of operation of the hand. The arc suppression device is an arc chamber that eliminates the sparks produced by the internal contacts on the operation. Any contact opens the load current and produces an arc (i.e., spark). Because the arc is conductive air column free into the extremely high temperature, it is by ampere right-hand rule, form a strong magnetic field in an arc chamber between the Fleming's right hand rule, the air conductor fast and elongated arc bending arc, the spark extinguished more quickly. If the load is motor, the normal start will have a high current, so it should choose 1.5 times ~2 times the rated current breaker.