1P, 1P+N and 2P circuit breakers are all used for the control and protection of single-phase power circuits. So what is the difference between them and the application effect?

1. Definition of 1P, 1P+N and 2P circuit breakers

• 1P circuit breaker — single-pole circuit breaker, with thermal tripping function, can only control live wire (phase wire), modulus 18mm;
• 1P+N circuit breaker — single-pole +N circuit breaker, which controls the live wire and the neutral wire at the same time, and only the live wire has the thermal trip function; the modulus is 18mm;
• 2P circuit breaker — 2-pole circuit breaker, which controls both the live wire and the neutral wire at the same time, with thermal tripping function, the modulus is 2*18mm=36mm;

2. Application of 1P, 1P+N and 2P circuit breakers

• Application of 1P circuit breaker: From the perspective of total economic cost, if the upper-level circuit breaker has a leakage trip function, and at least the incoming line (or the upper level of the outgoing line) is equipped with a leakage circuit breaker, the 1P circuit breaker can be selected, but Note that the superior power supply must be cut off during maintenance to prevent accidents caused by disordered live and neutral wires.
• Application of 1P+N (ie DPN) circuit breaker: To avoid the problems encountered by 1P circuit breakers during maintenance.
• Application of 2P circuit breaker: For the 1P and 1P+N circuit breakers with the same modulus of 18mm, because of the important influence of the space size, the "limit breaking capacity" of the former must be higher than the latter under the condition of short circuit accident . For the same reason, for some more important occasions, such as frequent maintenance and operation or power circuits that are prone to failure, it is better to use 2P circuit breakers (higher cost)