Earth Resistance

Now-a-days variety of chemical available. Second dig a parallel earth pit. Third is pour some salt water in to the pit.

It basically boils down to decreasing the soil resistance and increasing the surface area between grounding rods and the soil.

Earth electrode resistance

When you find that your earth electrode resistance is not low enough, there are several ways you can improve it:

1. Lengthen the earth electrode in the earth
2. Use multiple rods
3. Treat the soil

http://electrical-engineering-portal.com/improve-earth-electrode-resistance

Have you tried pissing on it?

That's what Signal Corps soldiers do.

I thought that is what Germans did to the MG-42 after a lengthy demonstration.

More information is needed regarding the site and what the ground it is built on consists of.

Also, where is the site as climate and other things like annual rainfall can make a difference as to which solution will work best.

Such a high resistance seems to indicate a very low moisture content ground soil or rock, and/or possibly a poor or non-compliant earth connection or joint (perhaps builder error). Have you checked these?

Is the existing earthing compliant or is it the soil that is the problem? Best to narrow it down as adding earthing pits (etc) may not help if the site earthing is not up to code.

Afterthoughts can be such a pity.

When the foundation concrete's poured it is a bit late.

If I remember correctly I think we had a similar question on CR4 previously and in the end they had to dig up the concrete to access the steel rebar to properly earth it.

Earthing Posts:

2007

http://cr4.globalspec.com/thread/14308/Earthing

2007

http://cr4.globalspec.com/thread/35453/Earth-Pit-Calculation

2007

http://cr4.globalspec.com/thread/13486/Electronic-Earth-Pit

2008

http://cr4.globalspec.com/thread/21385/earthing-pit-to-pit-rsistance

2008

http://cr4.globalspec.com/thread/30275

2009

http://cr4.globalspec.com/thread/43636/Earthing-Types

2009

http://cr4.globalspec.com/thread/43353/Building-an-Earth-Pit

2009

http://cr4.globalspec.com/thread/35453/Earth-Pit-Calculation

2009

http://cr4.globalspec.com/thread/45653/Earth-Resistance-Doubt

2011

http://cr4.globalspec.com/thread/68464/Testing-Earth-Resistance-Of-Earth-Existing-Pit

2011

http://cr4.globalspec.com/thread/73447/Elctrical-Grounding-Earthing

2012

http://cr4.globalspec.com/thread/77212/Neutral-to-Earth-is-Aprox-4-Volt

2013

http://cr4.globalspec.com/thread/86573

2016

http://cr4.globalspec.com/thread/107269/Earth-Pit

That's just the highlights from the first of ten pages of 'hits' to the search term "earthing pit". I discarded the threads with little useful information or responses.

That makes this thread a duplicate.

Tip a tanker-full of seawater onto it.

In the absence of seawater, try bovine urine.

Might also consider a counterpoise.

As opposed to an Avoirdupois?

_{Further-to Spades "GA" (Post2)}

... Looking thru BSR's links, I did not come-across an old post of my own-doing...that I would have expected to be "in-the-list".

So, I did a site-search myself (for a "KeyWord"), and found it :

^{. . . . . . ? ... only *2* posts .... Since January "08...?}

At "Corrosion Doctors.org" a good/succinct-and-to-the-point distinction is made between bentonite-based backfills and carbonaceous-type backfills.

As has been alluded-to, backfilling for earthing-type-electrodes (or instruments) is a science-unto-itself... thus, not fully understood by most (self included!).

One paper that I found quite eye-opening can still be found, here.

{..._{The more you know, the more you grow}...}

Motorola R-56...my grounding bible.

Welcome to the forum! GREAT resource that you reference... LOTS of expounding on every aspect, therein!

Not ONLY are the illustrations "varied-and-detailed"...

... but the VOLUMINOUS text is well thought-out and comprehensive, to say the least.

Though intended to be referencing the "structure-foundation" aspect (of installations"), the comment on pg 2-14:

"A soils engineer shall determine if the onsite excavated materials are adequate or suitable for use as backfill material. If the material is not suitable, then engineered soils shall be determined by the soils engineer" should be taken as "overall_gospel".

"Grounding electrode encasement materials (also known as backfill) shall be environmentally safe and approved by the environmental authority having jurisdiction." [See below]

4.4.1.4 GROUND PLATE ELECTRODES on Pg 4-19 reads as "Textbook" material... with Pg 4-20 adding:

"A grounding electrode encasement material should be used to backfill around the ground plate to help insure effective contact with the earth..."

and then, 4.4.1.5 CONCRETE-ENCASED ELECTRODES offers a consideration:

"Though concrete-encased electrodes (also known as Ufer electrodes, named after Herbert G. Ufer, or foundation earth electrodes) are not required by this standard, they should be used in new construction as a method of supplementing the grounding (earthing) electrode system (IEC 61024-1-2, section 3.3.5)."

"Concrete-encased electrodes (Figure 4-17) enhance the effectiveness of the grounding electrode system in two ways: the concrete absorbs and retains moisture from the surrounding soil, and the concrete provides a much larger surface area in direct contact with the surrounding soil."

Further, 4.4.1.9 GROUNDING (EARTHING) ELECTRODE ENCASEMENT MATERIALS on page 4-27 thru 4-28 "nails it", identifying the wide variety of materials available for backfilling... with the final "Shall Not" being a "Key" :

"Grounding electrode encasement material shall not have a corrosive effect on the grounding electrode system components."

What-a-biXch to go through a lot of major excavating and laying-out of a superlative grounding array ((though, I continue to wonder VIJIL, exactly *WHAT* is it for?!))... only to have "REDOX" render it useless.......................................

Thanks NDT...although I've been on CR4 for awhile...under another email/company. Luckily, I was able to keep my old CR4 name. I did a facility on Cape Cod where I went from 800+ ohm resistance to 4.95 ohm resistance. Yes, a lot of excavation, but great results.

Amen, the choir is now singing the chorus in unison. Very well done, indeed.

"Aye".... well .... we can ONLY *hope* that VIJIL can find his way back to the thread, here, and "Start-to-Begin" to...

"Help_US_help_him", by filling-in some more details.

My days of ranting about :

"poor posts"/"poorly-worded-questions"/"insufficient_info" etc. are "done".

To 'date', the sum-total of the OP's CR4 posting is this:

"we have to reduce the earth resistance to below 1 OHM. Now the reading is 18OHM. How can i optimise t below 1 Ohm?."

Perhaps he might at LEAST tell us where he is, or WHAT the purpose of his "need" is...

If you use iron bar completely seal the feed wire connection (made twice) using a bolted clamping plate because any rust or corrosion will increase the resistance. Ideally use a copper, or copper plated steel bar with earthing clamps.

Chose a wet area of low lying ground, e.g. near a down spout, or water outlet, overflow, etc. Ensure the bottom of the bar is at least 4 feet deep in to the ground. Splay the base if possible. Back fill with a mixture of soil and moisture retaining material, such as plaster, lime, etc. known to retain dampness. Ram down the back fill well.

Avoid using any free-draining materials, stone, gravel, sand, etc. all the way up from the base of the bar. These are best used for the last six inches of infill up to the surface, ground level.

Finally shield the immediate surrounding surface area against wind and direct sunlight while allowing exposure to rain water. Good job done.

I did my own like this and no resistance could be registered on the meter. None at all.
(official electric board meter.)

Hope this helps. jt.

An archaeologist discovered a mummified body deep in the sand and which was
about 2000 years old - but it looked strangely sad and miserable?
Excited by the find they carefully unwrapped the body and found it was in fact
the most miserable looking mummy they had ever seen!
The face was strained and looked so sad; with fists clenched in rage.
Carefully prising the fingers open they saw a slip of parchment and written on it
was, 200 on Goliath to win.