i never considered earth to be an especially conductive. It"s just dirt, after ~ all.

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However, I"ve seen "earth ground" conductive comb driven into the ground in order for power to it is in grounded, due to the fact that it will uncover its means down there.

However, it never made feeling to me why planet would even carry out such one effect: why electricity would stroked nerves to flow to dirt the end of all the conductive goodness inside the circuit?

What features of earth/electricity renders the current flow right right into the ground?


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In a nutshell

Electricity is not claimed to flow through ground stakes in common conditions. The doesn"t median its resistance is high, it"s in reality surprisingly small. The branch the the circuit is simply not closed normally.

In details

A ground is a referral point. You can litterally take any net in her circuit i beg your pardon is supposed to continue to be at a secure voltage and also call the ground. After every voltage sources produce a difference of potential (called a voltage) between two nets, regardless of what your potentials room - if they"re both addressed externally, there will certainly be a conflict and also bad things, but if among them is solved the other potential will adjust accordingly. Usually the ground is bring away such that we work with hopeful supplies predominantly, e.g. Floor on the - terminal that a rectifier bridge. The doesn"t average all the current flow through that, it"s only a reference.

The earth has mainly a person protection role.

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No current is claimed to flow in the Earth due to the fact that the actual supply circuit is isolated indigenous the Earth, however what if this isolation is endangered (wires eaten by rabbits, kids shoving their fingers in sockets...)? anyone is indirectly associated to planet (no isolation is perfect), which way that the circuit will now be closed and the only thing that will limit the existing going through everything is closing the circuit (e.g. People) is its interior resistance. Depending upon the environment, the resistance deserve to be sufficiently short to death someone; refer to this thread about what voltages are considered safe. To stop that, every enclosure is connected to planet (a Earth-R-Earth circuit has a near-0A current), and the electrical supply has a residual current device that compare the current going in and out, and cuts off the it is provided if over there is a leak (through Earth).

The planet is offered for one equipotential supply The electricity provider needs to defend its human being too, therefore the upstream supply is also referenced come Earth. Just like everywhere else. For this reason what wake up if the planet is not a an excellent conductor and its potential is not homogeneous? Users can be in contact with 2 different Earths, which deserve to be a high difference of potential (=voltage). Thankfully, moist in dirt and also water job are great conductors, but over all the equivalent cross ar of this fictive conductor is massive. Other than during quick upsets such as lightning, it has fantastic homogeneity in potential. Why use another conductor for ground which will certainly use much more copper and actually be less effective if we deserve to use what"s under ours feet?

The earth is likewise useful as a protection versus lightning: lightning is simply like any kind of dielectric/isolator breakdown, the occurs where the resistance between the charged cloud and the earth is minimal (see this amazing GIF). High trees, towers etc., and we can"t hazard relying on lucky alone so very conductive spikes are used to lure lightning, and also the planet is used to dissipate the energy. Loosely said. Generally lightning has enough existing flowing to create through planet and across human legs a voltage high enough to death them, so it is spread out much more evenly.