No, there is also a neutral line to the house and no current actually flows through the ground.

Bob

 

I don´t catch this

 

Ahhhh, now I understand, I wass missing the conections of the transformer to ground. Thank you very much Tonyr1084

So this diagram is correct? I didn´t imagine that the soil conducts the electricity so well.

BobTPH, YESSSSSSSSS

That diagram is not exactly correct. I can only speak to the United States electrical grid. It's common wiring for 240 VAC to be delivered to homes with two wires (Line 1 and Line 2). Each line is referenced to a center tapped transformer creating 120 VAC from Line1 to Neutral and another 120 VAC from Line 2 to Neutral. At the pole neutral is also connected to ground via a number of means (again, this is US wiring). Between Line 1 and Line 2 is where a home can get 240 VAC single phase.

At the home, the meter should be grounded and neutral should also be grounded at the house. Electrical outlets within the house should be connected to ground via the ground pin. Neutral typically (as far as I know it) goes to ground inside the breaker box where a separate line is provided for the ground wires. I'm not the best to explain it, but your drawing needs one more line from the transformer to the house. Line 1, Line 2 and Neutral. Again, neutral is grounded at the pole and at the meter. Typical house grounding is done to the cold water plumbing system - PROVIDED THAT it's some sort of metal pipe. PEX is not an acceptable ground. For one, there's no way to connect ground to a plastic pipe. Since my home is all PEX, I've had to run separate ground lines for all the grounded outlets. Grounded to the mast and grounded to a 9 foot steel with copper plating rod driven into the ground 8 feet deep.

The reason for all the grounding is because you can never be too safe. Not safe enough can result in injury or death.

 

Thank you very much. I have been reading about three phase current and now I think understand everything