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
sorry, there are some attempts to describe grounding, each one good to some degree, in the end too complex, missing the ELI5 point.
I’m neither physicist nor electrician (nor native english speaker), let me have an attempt, please downvote if wrong!
(i’m gonna repeat things that others said because they are correct)
The Earth works like a big dumpster for charge. It has basically zero charge, and because it is so big and massive, you can put basically endless charge into the earth, without changing the “zero charge” noticeably.
(probably not true from an advanced physicist’s pov, i’d be interested to learn more. But enough to explain our earthly problems.)
So the Earth is a massive Zero charge ball.
Electricity works in a way, that if there is higher charge at any point and lower charge at any other point, and if there is a connection between those two points, the higher charge immediately flows towards the lower charge point until they both are equal.
If you touch a power cable (the positive, charged line of a power cable), and you stand with your feet on the ground, you become the connection between the point of high charge (cable) and low charge (earth, massive zero charge ball), therefore the electricity will flow through you to the earth.
(the following is probably not true for other electrical proportions, but in our example of a massive power grid with huge powerplants vs. a human touching cable and earth:)
without any security measures (fuses and such) the source of power (the power plant) does not care, if the power that flows, comes back to it or if the power flows into the earth. it is like an open water pipe, it doesn’t care if you hit the bucket or if you spill everything on the floor, it just keeps pushing.
(this is why an GFCI-switch is important: it notices that the electricity is not flowing back to the source (difference between out and in), but goes somewhere else (the earth) and shuts off!)
And now, finally, what does the grounding do? the grounding is a third path for the electricity. (first path: from power plant to where it is needed (for example washing machine), second path: from where it is needed back home to the power plant)
the third path, the grounding, is a path from the place where electricity is needed (washing machine) to the ground / earth (massive zero charge ball).
Because: if any malfunction happens inside of your washing machine and something inside or the second path back to the power plant is broken, the power plant still pushes electricity into the washing machine (because the power plant doesn’t care), but it cannot flow back, so the electricity waits there.
if you now touch your washing machine (outside metal cover/parts), you become the connection between the high charged point and the earth, so you will be shocked by the washing machine.
the third path – the grounding, connects the metal parts of any device like your washing machine with the ground so that when an malfunction happens, the electricity flows right into the ground and does not wait there until you touch the machine and get shocked.
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