I have developed bad intuition and a lot of misunderstanding about how grounding works. For example, in this thread: Will a battery connected to the Earth eventually deplete?, the accepted answer is not what I expected. Like the person who originally asked the question, I thought that current will flow between the battery terminal and ground, because at least one of the terminals must have a different potential compared to ground (at least one, because the two terminals have a different potential compared to each other). It seems that this is not the case, moreover the other answer asserts that the battery doesn't "care" about the ground and that being connected to earth carries no special significance.
I still can't understand the explanation from the link, but thinking about this led me to a host of other questions such as:
- If I touch a two-terminal voltage source not connected to mains power (for example a battery or a stun gun) does that mean that current will only flow between the two terminals that I'm touching, and not also through my feet to the ground below? Is this true even if the source is an ideal voltage source?
- Is ground only "special" in respect to mains power, because in power distribution networks one of the wires is connected to the earth? Is a small amount of current passing through the ground at all time (because ground and the neutral wire are like two parallel wires)? Does that mean that during a ground fault event a large amount of current passes through the ground, so while walking on it we are not unlike birds standing on a power line? Is this safe in all cases?
- If the ground is not "special" in any way why ESD wrist straps work at all - it seems that the charge on a person's body will go to the earth, if a suitable path exists.
- The same question but in relation to lightning - if the earth is not "special" why lightning prefers to hit the earth, and not something else?
- I have noticed, that after getting charged with static, the discharge is very painful if I touch a metal object that is connected to the ground. The discharge is not painful if I touch the ground itself. This doesn't make sense to me - if the discharge is going to the ground, and the metal pole is highly conductive and "in series" with the ground, the current should be the same.
- Why birds standing on a wire don't get shocked when they land on the ground, that is, why they don't act as a capacitor that charges (on the wire) and discharges (on the ground)?
- Sometimes the earth is described as a "bad conductor" - but the earth is very large, so even if it has a high specific resistance, that resistance should be lowered by the fact that it is so large (the same way a thick wire has less resistance than a thin one). Why is this not so?
- I recently read that I should just think about the earth as a "reservoir" of electrons, where I can pull or push as much charge as I want - this explanation confuses me. If there are already a lot of electrons that I can 'pull', then 'pushing' them should be much harder. I can't understand if the earth behaves as something positive, negative or neutral, or all three at the same time?
Anyway, instead of polluting the site with such questions (I can think of more, lol), I want to ask - can you provide me with the fundamental knowledge on how ground (earth) works, so I can answer them myself? References to specific books/literature are welcome.