I'm installing some 110v Mini Split Air conditioners and want them on a separate breaker. The Main Panel only has 2 HOT wires coming in from the Mail Pole. The neutral wire is connected to the Ground Rod. My question is, "the Ac unit has three wires, Hot, neutral and ground. when installing the breaker, i know where the Hot wire goes but do i connect both neutral and ground to the Grounding rod or do just connect the white wire but then where do i connect the green one"? As mentioned, it's an older home but i just want to do this correctly. thanks
At the main panel only , neutral and ground are terminated at the same point or can be on the same buss. It may seam funny but this is how to do it in a main . In a sub panel the ground is isolated from the neutral to prevent a parallel path and or a path for objectionable current in code words. So with only 1 buss in the panel for ground / neutral take them both to that since it is the main. Never put more than 1 white neutral under a screw , but most panels will be listed for 2-3 ground wires under 1 screw , this make sense as the ground is only designed to protect for faults, Rare. But the neutral is the return path so it normally carries current and should not share a screw.
What comes down from the pole is actually 2 hots and a neutral. The power company does not deliver ground; you are expected to supply that yourself from your own ground rods.
We don't want neutral flying up to wild voltages (say: due to a transformer leak or something), so we clamp neutral's voltage to near ground voltage. We do that with a neutral-ground equipotential bond in the main service panel, and ONLY there. Everywhere else, neutral needs to be separate from ground or else bad things will happen.
So, your main panels intakes: Hot1, hot2 and neutral from the power company, plus ground from your Grounding Electrode System. You bond the last two. Then to your appliances you output hot, neutral, and safety ground.