I just purchased a 4hp, 3kW, 3phase motor for my table saw as an upgrade. The plate on the motor says it pulls 4.8-5.3Amps (~415V). My electrician reckons I need a 20Amp DOL switch with overload protection with a range of 4.5-6.5Amps.

But when I went to source a switch with these specks from the NHP range, I was informed that the overload protection specified seemed very low for such a large (i.e. 20 Amp) switch. They questioned whether I really needed a 20 Amper...? I was also told that such a switch is quite costly ($300 range).

What is the go here? Do I really need a 20Amp switch? And how do I tell what size switch I do need. I suspect that my electrician errs on the side of "overkill" which suits my personality. But I don't want to be ridiculous and spend money unnecessarily.

Any help is greatly appreciated! Regards, Luckyduck