I always thought AC current requires 2 wires to carry the current both ways just like DC. Recently I read a post on this sub saying neutral wires go to ground. What am I missing?

Question

I always thought AC current requires 2 wires to carry the current both ways just like DC. Recently I read a post on this sub saying neutral wires go to ground. What am I missing?

In: 19

Answer 1

Power lines don’t have a neutral wire. They have three wires with current being 120 degrees out of phase between them. So when on one wire the current goes “full forward”, it goes “half back” on both of the other two, and so on. So the current is always going in a circle, but that circle is being continuously shifted around those three wires. This arrangement is highly efficient in terms of conductor usage and is easy to adjust in terms of voltage.

Neutral is required for the single-phase power that we have at home. That neutral goes back to the electrical transformer where it’s usually grounded for stabilization purposes.