i want to wire a single phase 230v 22amp air compressor will # 10 wire work or should i use #8 it is about 120 feet from main panel and what amp breaker should i use?
At 120' if you use #10 you will have a 3.7% voltage drop. The max is 5%, if I was doing this I would bite the bullet and run #8 that way in the future if you needed to replace the compressor with a larger one you will have the capacity. Either way you need to run new wire with a ground so you can ground it properly. Use a 30 amp double pole breaker for this.
This is a 3 phase unit, so you should have a black, red, blue wires from the panel. Black to one connection, red to the next, blue to the last. Connect the ground to the ground terminal in the compressor controller. Maybe you could clarify the about the power panel.
With the distance you are from the power panel, it would not hurt the system to use the larger #8 wire and a #10 ground and the 30 amp breaker. The inrush current will be enough to lug the motor down when starting with a 10 wire. This will damage the motor over the long term.
10 wire should be just fine. Use a 30 amp breaker for this.
