How does grounding work

Question

I know that electricity doesn’t just dissolve in the ground, it must return to the power source. But once the electricity is in the grounding device, how does it find its way back to the substation if it can be relatively far away?

Edit: I know ground isn’t used in normal working mode and where I live there’s no grounding in sockets.

In: 469

Answer 1

In modern power distribution, we use 3 phase power. Even though your house may only have 1 phase, Somewhere back from the power lines its derived from a 3 phase substation.

In 3 phase power, each phase is running alternating current, and they are separated by 120 degrees. This means that the phases “pushing” power (positive part of the sine wave curve) is equal to the phases “pulling” (negative part of the sine wave curve), so that the 3 wires are both simultaneously providing the “hot” and the “neutral”, letting current travel in both directions. That’s not a technically completely accurate explanation of how 3 phase power works, but its an ELI5 explanation.

[This GIF might help](https://gifdb.com/images/high/three-phase-motor-running-electricity-4k2dfqnufs3knhi7.gif).

They still have a ground wire, but its only really to reference the power to ground potential, there is not a significant amount of current that flows in or out of the ground. While the neutral wire in your electrical panel at your house is tied to the ground, the current doesn’t go into the ground, it travels back to the substation through the neutral wire, or if the split phase power is balanced, all the power is transmitted through the 2 “hot” wires.

However you CAN use the ground as a current carrying conductor. This was commonly done 100+ years ago with telegraph systems, but there are pretty serious limitations with it. For example in the American Civil War and WW1, it was common for telegraph crews to run a single wire and then stick an electrode in the ground to communication between field stations. To my knowledge there was never any widespread power distribution system that used ground as a current carrying device.