[hemiblas]

All homes in the US and all commerical buildings have the neutral and ground interconnected at the main switchboard or main panel. This is also the only place they are allowed to be connected per the national electric code. Downstream of that if you have distribution panelboards they remain separate with separate ground and neutral busses in each panelboard. 240V single phase motors do not need a neutral to run(regardless of ampacity), generally we provide 2 hots(one from phase A and one from phase B) and a ground. The only reason you might have a neutral to an ac unit is if it had a screen of some sorts and a stepdown transformer from 120V to 12V were required. Then you would need the neutral to get the 120V, otherwise a neutral is not required for a motor.