Can a four-pole switch be used for the maintenance power supply?

Places where a 4-pole switch is required are generally the main incoming lines of a single unit and those for dual-power switching. The main purposes are as follows: 1. To disconnect the N wire at the incoming line connection, thereby preventing the N wire from being exposed to fault voltages that could cause harm to people, especially during power disconnection or when performing maintenance on the incoming lines； 2. At the dual-power supply switching point, it is primarily to prevent multiple grounding of the N wires of standby power sources such as transformers and generators, which could result in stray currents that interfere with the equipment. For a power supply that is used purely as a maintenance circuit, I don’t think it’s necessary to use a 4-pole switch. In Mr. Ren’s words, a 4-pole switch isn’t a good option; it’s better to use them as little as possible. The N wire carries less current than the L wire, so it has a weaker ability to remove dust from the contacts, which increases the likelihood of malfunctions. If a problem occurs, it may result in a power outage in mild cases, or even damage to the equipment or wiring in more severe cases. Those upstairs said it’s needed – please indicate the source and basis, and what is the purpose?

Can you guarantee that a three-pole setup will work as long as the potential at point N is equalized? Why must it be four poles or five poles?

It’s not necessary, right? What project’s maintenance power supply should use four-pole leakage protection?； Don’t even mention using electricity temporarily