1p, 2p, 3P and 4P refer to the number of poles of the miniature circuit breaker, which represents how many lines can be broken. The miniature circuit breaker is mainly the breaking line (L). Secondly, there are 1p + N and 3P + n. n is the zero line. When the miniature circuit breaker breaks the fire line, it also cuts off the zero line.

微型斷路器能夠分斷火線，主要是斷路器設置了脫扣裝置。假設有一個4P、20A的微型斷路器和一個3P+N、20A的微型斷路器，零線電流25A，那種微型斷路器會自動跳閘？

The miniature circuit breaker can disconnect the live wire, mainly because the circuit breaker is equipped with a tripping device. Suppose there is a 4P, 20A miniature circuit breaker and a 3P + N, 20A miniature circuit breaker with a zero line current of 25A, which miniature circuit breaker will trip automatically?

前面提到了微型斷路器的核心裝置，脫扣裝置，此裝置具有熱磁脫扣功能。

The core device of the miniature circuit breaker, tripping device, has the function of thermal magnetic tripping.

脫扣器采用的是磁線圈，當電流足夠大時產生的磁場力克服反力彈簧吸合銜鐵打擊牽引桿從而帶動機構動作切斷電路。

The release adopts a magnetic coil. When the current is large enough, the magnetic field force generated overcomes the reaction spring to attract the armature to strike the traction rod, so as to drive the mechanism to act and cut off the circuit.

例如，短路、過載都會引起電路中有很大的電流。短路不比多說，火零相碰即為短路，意思說電回路中沒有負載，只有導線和電源了，由于電源內阻和導線的線電阻是非常小的，在電壓不變的情況，突然整個電回路電阻變得很小，就有很大很大的電流產生，稱之為短路。過載一般是指用電設備的超負荷工作，工作電流超過了規定的額定電流。

For example, short circuit and overload will cause a large current in the circuit. Short circuit is no more than short circuit. Fire zero collision is short circuit, which means that there is no load in the electrical circuit, only the conductor and power supply. Because the internal resistance of the power supply and the line resistance of the conductor are very small, when the voltage remains unchanged, suddenly the resistance of the whole electrical circuit becomes very small, there is a large current, which is called short circuit. Overload generally refers to the overload operation of electrical equipment, and the working current exceeds the specified rated current.

微型斷路器接火線，必須要經過脫扣器，否則起不到短路、過載保護。例如這個問題，假設有一個4P/20A的微型斷路器和一個3P+N/20A的微型斷路器，零線電流25A，那種微型斷路器會自動跳閘？

The grounding wire of the miniature circuit breaker must pass through the release, otherwise it will not have short circuit and overload protection. For example, in this problem, suppose there is a 4P / 20A miniature circuit breaker and a 3P + n / 20A miniature circuit breaker with a zero line current of 25A, which kind of miniature circuit breaker will trip automatically?

根據上述可知，肯定是4P、20A的微型斷路器跳閘，3P+N、20A斷路器不會跳閘，除非把N線接到了P上面，本應接N的通道接了火線，才可能跳閘。

According to the above, it is certain that the miniature circuit breakers of 4P and 20A trip, and the circuit breakers of 3p + N and 20A will not trip. Unless the N line is connected to P and the channel that should be connected to n is connected to the live line, it can trip.