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Batteries have a circuit which looks like this :

enter image description here

The electrons go around the circuit and then return through the battery where they get charged again and flow around.

My issue is, what about alternating current? For example main power, simply it looks like this (pretend the globe is in your house)

enter image description here

Do the electrons return or go to the Earth? And how does it work when there is a short-circuit? Why does it go to the Earth instead of the neutral? Is it because of the lower electronegativitiy?

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"My issue is, what about on the grid?" I have slight problems to understand what you are talking about. Could you put your question in a simpler terminology leaving out your speculations? –  Robert Filter Oct 22 '13 at 7:18
    
Simplified it :) –  Blake Nic Oct 22 '13 at 10:00
    
It is difficult to understand what you are asking. What is this "globe" thing? In any case, AC looks like DC at any one point in time, it's just that the values change over time. –  Olin Lathrop Oct 22 '13 at 12:03
    
Pretend the active wire is the one coming into your house. A appliance is being used (doesn't need to be a light globe) and then the electrons exit through the neutral wire. Now where do those electrons go do they go back to the station or go to the earth wire. –  Blake Nic Oct 22 '13 at 13:29
    
@BlakeNic: your local power station doesn't produce electrons, it just recycles them. It's not like the water company where there's a one way flow and water ends up going down the drain. The local power station takes in electrons, adds potential energy to them and spits them back out again. You're just consuming the potential energy not the electrons. –  John Rennie Oct 22 '13 at 18:40
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In the UK (I'm not sure about other countries) the neutral isn't connected to the earth. The earth is just a safety measure. Basically it acts as a giant capacitor and soaks up any charge diverted to it, hopefully stopping that charge flowing through you!

In any case, remember that mains current is AC not DC so there is no net flow of electrons. The electrons just move to and fro at 50Hz (60Hz in the US).

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