You need a special switch if you want to switch 3 P and N - one where the neutral contact is set back so it closes early and breaks late, relative to the 3 phases.

If you do not do this then during opening and closing, unless loads are in perfect balance so you could cut neutral and walk away with it,  some loads  gets over and undervoltage when the neutral breaks first and there is a tug of war between the 3 load impedances to determine the new centre voltage.

4pole switches for 3 phase use have a clearly marked N terminal.

You may not care on a resistive or motor load that can tolerate up to 400V for a fraction of a second, but things like electronically ballasted lights do not like it at all, and do not work again after the briefest flash of 400v.  Sadly in a load imbalance of lights versus heating or cooking, lights generally come off worst, being the higher impedance.

In a single phase case the balance of risk is different, as even if neutral is not switched offset, the load only sees 230V or nothing.

Mike.

You need a special switch if you want to switch 3 P and N - one where the neutral contact is set back so it closes early and breaks late, relative to the 3 phases.

If you do not do this then during opening and closing, unless loads are in perfect balance so you could cut neutral and walk away with it,  some loads  gets over and undervoltage when the neutral breaks first and there is a tug of war between the 3 load impedances to determine the new centre voltage.

4pole switches for 3 phase use have a clearly marked N terminal.

You may not care on a resistive or motor load that can tolerate up to 400V for a fraction of a second, but things like electronically ballasted lights do not like it at all, and do not work again after the briefest flash of 400v.  Sadly in a load imbalance of lights versus heating or cooking, lights generally come off worst, being the higher impedance.

In a single phase case the balance of risk is different, as even if neutral is not switched offset, the load only sees 230V or nothing.

Mike.