# [b]Earth Farms[/b]

Discussion in 'General Electronics Chat' started by kevinv, Oct 17, 2003.

1. ### kevinvNew Member

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Does anybody know the correct way to calculate the total resistance of a number of earth farms in parallel?
I have read that that it is not the same as the fomula for resistors in parallel ie 1/Rtotal = 1/r1 +1/r2 +........1/rn but have not been able to find the correct formula can anyone help?

2. ### BrocktuneNew Member

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Ummm...what do you mean "Earth Farms"? You want to measure the resistance of parallel patches of land?

3. ### kevinvNew Member

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Earth farms

An earth farm is the term for a collection of earth rods driven in to the ground and coupled together to obtain a low resistance to earth for fault currents , as opposed to a single rod or mat.

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5. ### BrocktuneNew Member

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Re: Earth farms

Oh, I see...never heard the term before

I'm wondering now why it wouldn't be just a parallel combination of each rod's resistance. The rods aren't spaced out very far are they?

I'm willing to bet that the parallel formula, if it doesn't give the exact value in this case, would come pretty close at least.

6. ### NogginMember

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i would guess that the reason the formula doesn't work is because part of the rods are buried in the ground, which kinda puts the earth in paralell with the rod....

I'm kinda talking out of my ass though, I don't know shiznit about why the hell electricity wants to go to the actual ground instead of back to the power plant.

7. ### kevinvNew Member

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Earth Farms

Brocktune I am sure your right aabout the distance between the farms effecting the equation. the rods in any one farm are spaced at approx the driven depth of the first rod (this depth is determined by a test) and the number of rods driven in parallel is determined by the initial test. So for instance dependant on the ground condition you could have 4 rods 3 meters long spaced 3m apart in one farm. However the farms are approx 1Km apart and it is the equation for the farms in parallel that I'm trying to get.
Noggin the neutral of a power plant is connected to earth

8. ### seekerNew Member

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Hi kevinv,
Do you have any URL's that might have some info on earth farms?
Is there another term for earth farms?
I have heard of everything from ant farms to antenna farms to zebra farms but not an earth farm Maybe if some of us could get a bit more information on the term we could be more help to you.

Thanks...Tony

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