How to deal with the neutral line of fan fire distribution box?

Fan fire distribution box is applied to the fan. When redesigning the fan fire distribution box, it also needs neutral line design. Some of them have a common neutral line, while others do not. So how do we connect the neutral line?

Although the old fan fire distribution box has been used, with a common neutral row, but now the use of less and less, this kind of neutral line design is not controlled by the switch, is not very safe. Its main switch is connected with a live wire and a neutral wire, this connection is not safe, so we should not learn this. The current neutral line design, is through a live wire and a neutral line, respectively connected to the opening of the air switch and the common neutral row above, can use the air switch for separate control, so their separate design, let the fan fire distribution box use more safe.