Electronic – Why does the power company provide a neutral line


I understand that power is often transmitted in 3 phases (with no neutral). Then, when we get to a certain substation, the power company basically gives house 1, L1, house 2, L2, house 3 L3, and connects them all to a common neutral line. That is, each house gets one phase of power and a neutral shared between all 3 lines. Then, that neutral is grounded to earth at the substation.

It is also my understanding that in the main panel in my home the neutral is tied to ground. It seems to me, if we are going to do this, why do we need the neutral wire at all. In fact, in any system, if the power company actually grounds the neutral wire at the substation, why can't each individual house simply provide its own neutral (i.e. each house has a single phase and a metal pole or two out in the back in the ground that serves as a neutral (current carrying earth ground) and a ground (for safety)). It seems to me this would save the electric company from having to provide a neutral wire. My point is is that the neutral wire is earth grounded at the substation and in each home, so why is it even necessary to provide it?

In my setup, current would flow from the 1 wire coming into the home from the pole (single phase) and current would flow to an earth ground provided at each home. There is no reason for the power company to provide the neutral.

Can you fix my misconceptions please? I have read many posts and I get conflicting or contradictory information about this.

Best Answer

A voltage is a potential difference between conductors. For instance the difference between the live and the neutral wire.

The power company delivers these two lines to ensure the potential difference to the customers. If it would only supply the live wire and the ground of a local customer is used, it's unknown which voltage the customer receives.

It is because there is no knowledge about the potential difference of neutral between the power facility and your house. It can be higher or lower. And then the resulting voltage on your devices can also be higher or lower.