Grounding Under/Below 10 Ohms!

Hai

you can try to install Maintanance free eathing system . because this earthing system consider special material / component to improve the ground value . some body call (or) another name is double earthing system.

Thanks

by Bala

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So how about saturating the ground near the earth pit with a tanker-load of seawater?

Or install a lot of ground rods and a tightly spaced ground grid.

Like the man said. Pee on it.

Hai, For my siggesstion your reading is very high,no more chance to get less than 10Ω,But for my experience,i got some good value of resistance by using bentonite,salt water,Charcole.you also pour some salt water in your auxillary electrode.

hi..use gypsum,bentonite,sodium sulphate mixture ..one of the best way

Dear compressor,

I have the same problem when I installed the 150 kV LSA grounding up the hill.

First of all, I put more grounding rod ( up to eight rods, 2.4 mtr long) at least 6 to 8 mtr apart and then I linked all of them.

Each grounding rod embedded in to a 1 mtr x 1 mtr hole with 2 mtr depth, each hole I filled at leastwith 25 kg of portland cement mix with 10 kg carbon powder.I did it as how the civil contractor usually do for building cement mixing.

The result is quite good, some of them can reach down to 7 Ohms, in certain place can be as low as 4 ohms.

Please try it.

best regards,

Stanyadji

The Methods as Peter T suggested are very good. if you still not able to get the required resistance then do the soil test. if you believe you have a water table below than better you make a hole as deep as possible. i have seen earthing pits upto 12 meters, then a complete filling with bentonite and copper earth rod will do the trick.

All methods can be done but you have an idea about the soil you are using, since you have not mentioned the area or type of soil used its diffiult to say any precise method.

hi

excavate and clear the earth from the earth pit from existing earth fill up with bentonite,salt and charcoal i had excellent results , Bentonite has the property of resistence moisture and reduces the Resistance for flow of current you need to water the earth pits on an on going basis then decide the periodicity of watering good luck

crm

Dear Compressor,

Most of our colleagues on this forum have given you good methods of chemically treating the soil to bring down its resistance. But nobody has given you the method of calculating number of rods to bring down the resistance. I am suggesting the following:

Mathematical expression for Rods arranged in a hollow or solid square is as under:

Resistance of N rods in parallel / Resistance of one rod = (1+kx)/N

where k is a constant and depends upon no. of rods used.

N is the no. of rods in parallel.

x = [L/(ln 48L/a-1)]/d

where

L = Ground Rod length (cms)

a = Ground Rod radius (cms)

d = Distance between two parallel rods

Hollow Square - Solid Square

* * * *****

* * * *****

* * * *****

Values of k/ total no. of rods = 2.7/4;4/8;5/12;6/16;6.5/20;7/24 for hollow sq.

= 6/9;8.5/16/11.5/25;14/36;17/49 for solid sq.

Hope this will help you to arrive at no. of rods required to achieve your target of 10 Ohms.

All the best

BB Raina

Hi Guys!

Please help: I am still working on this grounding thing. The ground reading got down to 17 ohm. I could have drawn something if I new how to make it happen in this site, but any way: As I said I got the reading from one of the grounding (call it A)to the potential (P) and the current(C) as 17 ohm. I have A separated from P as 10m and from P to C as 10m. But when I reduce the distance from C to P as 8,5m I got a reading of 88 ohm! Would someone explain me in a rational way what is happening?

I am using a SEW Standard ST-1520

I also have a SIRIUS 87, but would not read below 50 ohm, I mean when the the ST-1520 is reading below 50 ohm the Sirius 87 would give the following message(for some reason!): Att

Would someone tell me what is wrong with the Sirius 87?

Thanks, Compressor