Function of Neutral Block

In the household distribution box, only when 1p circuit breaker is used, neutral block is needed

It has only one set of terminals (one at the top and one at the bottom), and can only connect one wire. Of course, we have to connect the live wire here. As for the neutral line in the circuit controlled by this switch, it is taken from the neutral block.

In other words, only the live wire in this circuit can be controlled on and off. The neutral line can not be controlled by the branch circuit breaker because it is not switched on (the neutral line is in the on state regardless of whether the branch circuit breaker is off or on).

If there is no 1p circuit breaker in the distribution box, there is no need for neutral block, which is the reason why there is no neutral block in many distribution boxes.

In recent two years, 1P + N switch has been used instead of 1p switch in new household distribution box.

It has two sets of terminals blocks, which can be connected to the neutral line and the live line at the same time, so there is no need to use the neutral block. Moreover, the safety of the switch is higher than that of the 1p switch. When the switch is turned off, the neutral line can be disconnected at the same time.

More importantly, the size of 1P + N switch is the same as that of 1p switch, which can perfectly replace 1p switch without increasing the size of distribution box.

Therefore, with the decrease of circuit breaker price, 1p circuit breaker is gradually abandoned by people. In the household distribution box, the total cost of installing neutral block for one or two 1p circuit breaker is similar to that of two 1P + N circuit breaker.