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If I grab hold of a live wire, current will flow through me and into the earth.

If there is an electrical fault in my home, current will flow through the earth wire, out into a ground stake and into the earth.

If enough static electricity builds up in the clouds it will be discharged to the earth through a lightning strike.

What is so special about the earth? Why does current "want" to go there?

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  • $\begingroup$ It doesn't. It wants to flow in loops, and static electricity wants to equalize. $\endgroup$
    – user253751
    Apr 22 at 12:22

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user253751 said, "[electric current] only flows in loops."

That's true, but what that user didn't say is that the electrical grid is connected to Earth in many places. There is a loop from the transformer outside your house, through the "live" wire, through you, through the Earth, through a long metal stake driven in to the ground near the transformer, and back to the transformer.

The grid is grounded like that to prevent atmospheric phenomena (the same that cause lightning) from building up dangerous static charges on overhead wires.

The current to any small appliance in your home is supplied by two wires. One wire sometimes is known as "hot," and the other is known as "neutral." The neutral wire is connected to Earth. If you touch it, then you won't feel anything. The "hot" wire is the one you don't want to touch. The voltage on the hot wire relative to Earth can be anywhere from around 110 V to 240 V depending on where in the world you live.

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    $\begingroup$ Important note: If there is a wiring problem (e.g. broken wire) then the neutral wire can be dangerous to touch. That's why a separate earth/ground wire is used in home wiring. $\endgroup$
    – user253751
    Apr 22 at 18:31
  • $\begingroup$ @user253751 why is that? I knew that this is the case, and the one thing that doesn't 100% make sense to me is how can you get a shock off of neutral if it is tied to ground? $\endgroup$ Apr 22 at 21:24
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    $\begingroup$ @StephenBrown because if the wire breaks then it won't be tied to ground any more. It will be tied to live (with some resistance). Safety standards are written in blood! They do not just think about what happens normally, but also what happens if something gets broken somehow. $\endgroup$
    – user253751
    Apr 23 at 10:22
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The history of how the conductivity of the earth was first used is interesting.

Long-distance electromagnetic telegraph systems from 1820 onward used two or more wires to carry the signal and return currents. It was discovered by German scientist Carl August Steinheil in 1836–1837, that the ground could be used as the return path to complete the circuit, making the return wire unnecessary. Steinheil was not the first to do this, but he was not aware of earlier experimental work, and he was the first to do it on an in-service telegraph, thus making the principle known to telegraph engineers generally.

So using earth as a "ground" is a consequence of the fact, that the mass of earth has a conductivity.

For lightning

Lightning

In the end, a storm cloud becomes polarized with positive charges carried to the upper portions of the clouds and negative portions gravitating towards the bottom of the clouds. The polarization of the clouds has an equally important effect on the surface of the Earth. The cloud's electric field stretches through the space surrounding it and induces movement of electrons upon Earth. Electrons on Earth's outer surface are repelled by the negatively charged cloud's bottom surface. This creates an opposite charge on the Earth's surface.

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As the electrons of the step leader approach the Earth, there is an additional repulsion of electrons downward from Earth's surface. The quantity of positive charge residing on the Earth's surface becomes even greater. This charge begins to migrate upward through buildings, trees and people into the air. This upward rising positive charge - known as a streamer - approaches the step leader in the air above the surface of the Earth. The streamer might meet the leader at an altitude equivalent to the length of a football field. Once contact is made between the streamer and the leader, a complete conducting pathway is mapped out and the lightning begins.

So it is a different path, not a "general attraction" as you seem to think.

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