The neutral is used as the return path for the current used by the AC device. The ground is used as a safety wire. If a device should become 'energized' because of an internal failure or some other means, then this energy will be diverted to ground and the device will no longer be energized. This is why you see three connectors in a wall outlet, hot, neutral, and ground. Now if your talking 3 phase power then thats a different story. Hope this helps
It is a current-carrying conductor. In a three-phase system it carries any current due to current differences in the three phase leads. It is also used for line-to neutral loads in a three-phase system, e.g. 277V loads on a 480V system.
It is generally grounded. In a typical (U.S.) single-phase service, you get three wires from the utility - two "hots" and a neutral. The neutral is connected to a center-tap on the secondary of the service transformer (and to ground). You have 120V from either hot leg to neutral and 240V between the hot legs. If your 120V loads are perfectly balanced, you will have no current in the neutral running back to the transformer, but you will still have current in the individual branch circuit neutrals.
