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Why Earth Fault Back To Source

01/30/2017 1:29 PM

Why earth fault current flows back to only its unique source from which originated. i mean when fault current enters the soil , how do the electrons know where to go? i mean every source neutral is grounded.so every source neutral appears to be at same 0Volt potential to electrons? i know about conservation of charge but want to know from practical point of view. consider circuit below where load 1 has a fault.then why does not this fault current go to the neutral of source "G2" instead of G1 .G2 may be closer to fault point than G1 and hence electrons will prefer to follow the least resistance path.any idea? (again i know conservation of charge law)

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#1

Re: Why earth fault back to source

01/30/2017 1:42 PM

They use E2E which is electron to electron communications modeled after the automobile industry communications protocol for V2V. Each electron communicates with its neighbor that they are getting too close and to shove off.

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#2

Re: Why earth fault back to source

01/30/2017 2:20 PM

What he said, that if they start piling up in one location it is a day of extremely high potential indeed, and there will be a huge spillover effect in rapid trading down of potential to local users.

The stones in this case do bear witness.

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#3

Re: Why earth fault back to source

01/30/2017 2:31 PM

The renowned physicist, Dave Barry, explains it all...

http://www.comp.leeds.ac.uk/Perl/Misc/electricity.txt

This should answer your questions.

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#4
In reply to #3

Re: Why earth fault back to source

01/30/2017 2:52 PM

Excellent source of electronic information. This is why pearls of wisdom can never be left on a wet floor. - They become slippery when wet. Electrons are even more round and slippery when wet.

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#5
In reply to #3

Re: Why earth fault back to source

01/30/2017 2:56 PM

Excellent, everyman's explanation of electricity.

It is my understanding that Professor Barry studied under and was a protege of the famous poet, scientist and philosopher Brother Dave Gardner.

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#6
In reply to #5

Re: Why earth fault back to source

01/30/2017 3:03 PM

Was Dave Gardner that old boy that used to prank call people, and ask, "How big an old boy are you?" "Do you want me to open a can of whoopas on yoo?"

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#7
In reply to #6

Re: Why earth fault back to source

01/30/2017 3:23 PM

I don't think so.

He was a drummer, singer and comedian. "White Silver Sands" was his, and "The Motorcycle Story".

My brother and I used to listen to him on the radio in the 60's.

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#8
In reply to #7

Re: Why earth fault back to source

01/30/2017 3:39 PM

Either way, I am sure I would have enjoyed, and listened. The older music to me was actual music.

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#9

Re: Why Earth Fault Back To Source

01/30/2017 8:10 PM

In highly-simplified form, this is the "view" your top circuit "sees" before the short:

-----

and during the short:

Does this help?

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#14
In reply to #9

Re: Why Earth Fault Back To Source

01/31/2017 2:33 AM

Unless that circuit contains some sort of overcurrent protection arrangement the life of either the conductors or the power source or any individual in the vicinity during the short is likely to be considerably foreshortened.

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#17
In reply to #14

Re: Why Earth Fault Back To Source

01/31/2017 7:48 AM

G1 is a dud 2V battery.

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#20
In reply to #17

Re: Why Earth Fault Back To Source

01/31/2017 8:23 AM

Ah! That explains everything. Thanks.

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#10

Re: Why Earth Fault Back To Source

01/30/2017 8:12 PM

Electrons go where they want.

It's like herding cats.

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#11
In reply to #10

Re: Why Earth Fault Back To Source

01/30/2017 8:28 PM

Herding cats is easy; you just have to know how to do it: strap a dead fish behind the saddle and ride in front. They'll follow you anywhere - in this case, back to G1.

What coolyaar has either forgotten or doesn't realise, is that there is an electric field - a voltage gradient (the aroma of dead fish, if you will, wafting in the breeze) - which guides the motion of those electrons. That field exists between the short and G1, and doesn't even see the bottom circuit; especially so given that it is grounded at a single point (note to coolyaar: a single point does not a path make). As far as those electrons are concerned, G2 and its load don't exist and never did.

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#12
In reply to #11

Re: Why Earth Fault Back To Source

01/30/2017 8:33 PM

"What coolyaar has either forgotten or doesn't realise" or never knew and was too lazy to discover on his own?

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#13
In reply to #12

Re: Why Earth Fault Back To Source

01/30/2017 8:41 PM

We can only speculate.

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#15

Re: Why Earth Fault Back To Source

01/31/2017 2:48 AM

"(again i know conservation of charge law)" sic

Obviously you don't!!

The law states in essence that the "total charge in a given space is equal to that which is entering minus that which is leaving", it cannot be greater or lesser than that.

So..In your example, charge leaving G1 is accumulating in G2.. Therefore G2 now has an excess of charge and G1 a deficit...Not possible under the law that you apparently know.

Another part of the law called the "continuity equation" states that "the amount of charge at any point can only change by the value of the charge entering or exiting that point", and since the total cannot be more or less than equilibrium, the charge MUST flow back to its source, no matter how far away that is, or what obstacles are in its way.

Geez, I think I'm beginning to look forward to this dill's posts.

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#16

Re: Why Earth Fault Back To Source

01/31/2017 3:44 AM

Is this thread about cast iron bathtub removal, by any chance?

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#18
In reply to #16

Re: Why Earth Fault Back To Source

01/31/2017 8:05 AM

"Over my dud body!"

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#21
In reply to #18

Re: Why Earth Fault Back To Source

01/31/2017 8:24 AM

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#22
In reply to #16

Re: Why Earth Fault Back To Source

01/31/2017 9:37 AM

I think it has to be, since charge accumulation in a Chevy Cavalier results in implosion of everything within 100 meters (100 yards is OK, however, since that is English units).

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#23
In reply to #22

Re: Why Earth Fault Back To Source

01/31/2017 9:47 AM

So are we advised to stay 100m away or 100 yards away? 109 yards or 91.4m? Does charge vary with distance? If so, if I stand further away from the supermarket cashier will I be charged less? If my potatoes accumulate a charge, will they implode or taste the same as mashed? Please advise.

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#25
In reply to #23

Re: Why Earth Fault Back To Source

01/31/2017 1:15 PM

Charged potatoes should explode. You did catch the joke about being within 100 meters when being within 100 yards is OK. Happy for you.

It depends on how hot the cashier is. If normal, then the air will be charged only the usual amount by static.

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#27
In reply to #25

Re: Why Earth Fault Back To Source

01/31/2017 1:22 PM

OH yes, I am on the ball.

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#19

Re: Why Earth Fault Back To Source

01/31/2017 8:21 AM

Electron are quite clever and they have homing instincts like pigeons, they now how to come back.

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#24

Re: Why Earth Fault Back To Source

01/31/2017 10:10 AM

He doesn't give up demonstrating his complete lack of even the simplest electrical knowledge, does he?

I guess he is the modern equivalent of what were called "trolls" on the internet....

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#26
In reply to #24

Re: Why Earth Fault Back To Source

01/31/2017 1:16 PM

Standing in front of a hot pizza oven all day has fried his brain.

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#28

Re: Why Earth Fault Back To Source

02/01/2017 7:24 AM

Coolyaar left out the obvious (as usual). All your 4 earths will be interconnected by conductive paths, which could be represented by resistances for simplicity.

Earth is a very vague concept for making a practical electrical system. Other than where minimum cost is essential, early telegraph & HV systems come to mind, earth is not used as a return conductor.

Where an earth return is beyond control, as in open wire HV systems, much thought is devoted to quick detection & disconnection of earth faults and the making of earth connections where necessary ( even power stations have to be satisfied with about 0.5 ohm earth resistance).

This is because "earth" can vary between a mudflat washed by the salty sea and clean dry sand, basically what good fuses are filled with, so they are open-circuit when the wire has melted.

Taking a typical building as an example, your earth on Load 1 is a protective conductor run back to the PEN & connected where it comes into the building. This is because safety requires that a fuse will blow quickly to isolate a shorted or overloaded circuit and the potential on the conducting case of Load 1 must be limited.

Any real earth return is likely to be such high resistance it will never blow a fuse in an LV system - this is why a damaged hedge-trimmer cable in a shallow outdoor pool of water is lethal and the first target for "domestic earth leakage breaker" use in the history of electrical regulations.

Spend time thinking about that and the substantial Tome of "Wiring Regulations/Electrical Code" before worrying about the fate of the electrons on your comb after you have used it on your hair!

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