What's the difference between 1P, 2P, 3P and 4P circuit breakers? How to choose?
Let's get to know each other! For miniature circuit breakers, 1P+ N, 1P and 2P are commonly used as single-phase electrical control, but the effect is different.
1p for single open, only broken wire, generally used for light or electricity small electrical equipment
2p for two, two for the line end, the line of fire, zero line, more commonly used.
3P is three open, for control of three phase electricity, three incoming line end and three fire lines, generally three - phase electric bus switch and three-phase electrical equipment application.
4p is the addition of a terminal on the basis of the three opening, which is the N representation of the zero terminal.

1P - single pole circuit breaker, with thermal magnetic tripping function, only control the fire line (phase line), module 18mm.
1P+N - single pole +N circuit breaker, and control the fire line and zero line, but only the hot wire has the function of thermal magnetic tripping. When N line is non-protective pole or open and closed neutral pole, the modulus is 2*18mm= 36mm;
When N lines are not open neutral, the modulus is 18mm. A circuit breaker with residual current protection on a single pole.
2P - single - phase 2 - pole circuit breaker, which also controls the fire line and the zero line, and has the thermal magnetic tripping function.

Selection of circuit breakers
1. In order to reduce project cost in the lighting loop, a 1P circuit breaker is usually chosen. It is important to note that the superior circuit breaker must have the function of leakage and deduction, and the superior power supply must be cut off
2. The power maintenance in order to prevent fire and zero line to meet the said (when wire and zero line after the 1 p disconnection from the zero line and no broken wire), can be used by 1 p + N breaker, which often said DPN circuit breaker.
3. There is a difference between 1P and 1P+N for the shell of the same size of circuit breaker, the former is more than the latter in the state of short circuit accident. Therefore, it is recommended to use 2P circuit breaker for the more important circuit and frequent maintenance and operation loop of the project, but the cost is higher.
In addition, 1P and 2P are used for single phase, 3P and 4P for phase 3.
When protection is zero, only 1P and 3P can be used. When protecting ground, it is better to use 2P and 4P.
1P+ N: only install the protector on the phase line and disconnect the phase line at the same time.