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
So firstly, electricity doesn’t need to flow back to its source! It goes from high to low. On a battery, it looks like it flows back to the source, but thats because the battery has a high and a low side. You’ll probably have seen the + and – signs on the side of the battery? That’s what those are. With a substation, its not recycling electricity, the substation is constantly getting new electricity from the power plant.
You can kind of think of electricity as pressure. Typically water pressure is used as the example, but when we talk about grounding I think its easier to use air pressure.
Imagine a battery with just a + side. Its got a certain limited electrical potential, and it needs a – side. In our example its like a balloon, filled with air at a higher pressure than the atmosphere around it, and that air wants to get out.
When we want that battery to power something, we use the difference in the electrical charge to move electrons and generate electricity. With our balloon, we use the air pressure in the balloon to make things happen.
So, what happens if you don’t have any difference? What if the balloon was hooked up to a tank with the same air pressure inside?
Well, nothing happens. There’s no difference, and you need that difference in pressure to make the air move and do work. The same thing is true for electricity. If we have two sources both at the same electrical charge, then no current flows, no work gets done, no lights turn on.
So how do we make sure we always have a difference? The simplest answer is that we attach our balloon to a hose that, after flowing through some machinery to do work, leads to the outside air. We now have a consistent flow from source to outside air regardless of how high (or low) the pressure in the balloon is! The same thing applies to electricity, except instead of using just the atmosphere, we use the whole Earth itself.
Basically, electricity is all about a difference between two electric charges. We can (and do) make these differences ourselves, but thats work that a lot of the time we don’t need to do.
For the electricity that you use in your house, it flows from the power line, through your appliances and lights and computers, and then out into the earth.
So where does it go from there? Well, the earth is a pretty huge reservoir of electric charges. Itd be like taking water from your tap and pouring it into the ocean. Is there more water there than before? Sure, yeah. Does it make a difference to the ocean? No, not really.
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