Wyleisdeisels is correct. That is not a true 5hp. If I recall correctly 1 HP equals about 750 watts, so 5 HP is 3750 watts. At 230 that's 16amps.
So your fine with 12 gauge line and 20 amp connectors even if it was a true 5hp. I always wonder how they come up with HP ratings on motors. Air...