Powering a 230v air compressor
I believe you also need a magnetic starter switch, if not the compressor will drag everything in the house down when it starts
Magnetic starters have nothing to do with "dragging everything down."
(You are probably thinking of a "soft starter" or other terminology)
A magnetic starter is simply a relay or other term, contactor. "In the box" these starters normally also include motor overload protection, IE in addition to fuses or breakers. As motors (compressors) get larger, the pressure switch has to carry more and more load. A motor starter allows the pressure switch to operate a contactor instead of switching the motor directly.
Very very large HP motors, larger than anything most of us will ever see in our private shops, do use reduced current starting methods, of several means, including reduced starting voltage, reactive components, and resistance in field controls Depends on the application.
But a soft starter of some sort would only normally be found on something like 12--15HP single phase, or more than 20-25 HP three phase systems.