Tag: circuit breaker

1P, 2P, 1P+N, 3P, 4P, 4P+N, P means that the miniature circuit breaker (MCB) is equipped with a protective pole (knife pole), N means that the neutral conductor is only equipped with knife pole, but no protection modules. Both 2P and 1P+N are called two pole switch, 4P and 3P+N are called 4 pole switch. Neutral conductor of 1P+N and 3P+N don't have protection, so they are much cheaper, the neutral conductor pole acts along with the phase line pole. Some circuit breakers divide 1P+N into two types: one adopts two module width, another adopts one module width (small size). For these poles, how to select a right miniature circuit breaker?

Whether low-voltage circuit breakers are installed properly, which will directly affect its performance and safety. Generally pay attention as follows:

1. Before installation, the technical parameters listed on the nameplate of the low-voltage circuit breaker should be checked for compliance with the requirements.
2. Low voltage circuit breakers should be installed vertically, and the wired in front of the board are allowed to be mounted on metal brackets or metal backplanes, but the low-voltage circuit breakers that are wired behind the board must be mounted on the insulating base plate. The bracket or bottom plate of the fixed low-voltage circuit breaker must be flat to prevent damage to the insulating base when the screws are tightened. In order to prevent accidents caused by arcing, the copper busbar of the low-voltage circuit breaker should be packed with 200mm insulation or phase-interval arc plate from the insulation base.

Circuit breakers and fuses can protect the electric equipment and lines from short circuit. Actually, both have their own characteristics. Circuit breakers are used to switch on and off the load circuit as well as cut off the fault circuit, so as to ensure the safety. The fuse is used as a protector by melting itself when the current is too high or exceeds the load current. It is completely different from the circuit breaker on the breaking current. Its function can be easily understood by the commonly used fuse in our home.