HOW FREQUENTLY GROUNDING RESISTANCE NEEDS TO BE INSPECTED ??

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GoldDigger said:
The voltage versus current curve will be linear unless there is a semiconducting surface layer.
But when the rods are within each other's zone of influence the R values you calculate will not correspond to the idealized resistances between each isolated electrode and "the earth". Which also means that you cannot get the resistance of the triad from those results.
If the three electrodes in question are miles apart and not near any conductive elements embedded in the earth your method might work.

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When they are miles apart you have to factor in resistance of your test leads.
 
Quote:

"Measurements made with a dc multimeter are subject to distortion by electrical noise in the soil. A multimeter offers no means of verifying that the resistance displayed represents anything other than an arbitrary measurement between two convenient points. With a multimeter, one can measure the resistance of the soil between a ground electrode and some reference point, such as the water pipe system, but a fault current may encounter a higher resistance. Genuine ground testers are amenable to field-developed standard procedures that have built-in cross-checks that expose insufficient test conditions."

 
Grounding Checks SHOULD take installation environment into consideration

Grounding Checks SHOULD take installation environment into consideration

Anwar Pasha said:
Is there a Code or standard that stipulates a time period, within which the testing of Earth Resistance for an installation must be carried out to see whether the earthing system is working or not??
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Anwar,
Although the other posts may be correct as to the NEC not stipulating when these grounding tests should be done that does not prevent local governments and good common sense dictating otherwise!!!!!!

As my title states: Grounding Checks SHOULD take installation environment into consideration

And I actually think that way!

If the location the ground system has been installed within tends to erode grounding and/or bonding conductors then developing a sensible testing schedule is quite smart.

After all, why wait for a problem to happen in-order to find out what that problem is?

Proactive testing of grounds and/or bonds just makes good engineering sense when you know that the installation environment (whether due to natural or man-made causes) is more likely to cause a premature failure unless proactive steps are taken.

And since I spent the vast majority of my 20+ career years in the Testing industry, I will ALWAYS lean to the 'too much testing' rather than the 'didn't test enough' paradigm!

I would suggest initialing consulting such companies as Megger ("http://www.megger.com/"), APC ("http://www.apc.com/us/en/"), and TrippLite ("https://www.tripplite.com/") via there 'Tech Guides' sections as a start for creating your own Grounding Checks schedule.

Hope this helps!

Anthony

Only a fool asks 'Why bother?'

Soil Ground Characteristics.jpg
 
anthconway said:
Anwar,
Although the other posts may be correct as to the NEC not stipulating when these grounding tests should be done that does not prevent local governments and good common sense dictating otherwise!!!!!!
As my title states: Grounding Checks SHOULD take installation environment into consideration
And I actually think that way!
If the location the ground system has been installed within tends to erode grounding and/or bonding conductors then developing a sensible testing schedule is quite smart.
After all, why wait for a problem to happen in-order to find out what that problem is?
Proactive testing of grounds and/or bonds just makes good engineering sense when you know that the installation environment (whether due to natural or man-made causes) is more likely to cause a premature failure unless proactive steps are taken.
And since I spent the vast majority of my 20+ career years in the Testing industry, I will ALWAYS lean to the 'too much testing' rather than the 'didn't test enough' paradigm!
I would suggest initialing consulting such companies as Megger ("http://www.megger.com/"), APC ("http://www.apc.com/us/en/"), and TrippLite ("https://www.tripplite.com/") via there 'Tech Guides' sections as a start for creating your own Grounding Checks schedule.
Hope this helps!
Anthony
Only a fool asks 'Why bother?'

View attachment 20092
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Not being flippant on most of what is being said, I think that it makes a lot of engineering sense to be able to determine the integrity of the grounding system on an ongoing basis.

However, this is a kind of “pie-in-the-sky” idea that is untenable on most situations.

As I have mentioned earlier in the thread, I asked whether some quantifiable algorithm that can be applied in order to come up with a procedure or system to accomplish this testing on prior installed grounding systems. I never ever got an answer--- instead quite a bit of some glib response.

It is true that environment could have severe impact on the grounding materials installed.

Proactive steps to prevent premature failure sounds to me as an exercise of hindsight. Shouldn't it be more effective or unincumbered if during the planning stage, soil conditions that could affect the serviceability of say certain material that can withstand the corrosive attack of the material used for grounding rod be performed first?

The twenty four grounding poles for the Pacific Intertie, 500 KV DC power distribution that stretches over 800 miles from Oregon to Southern California that ends at the terminus in Sylmar CA., are buried in the ocean floor about 20 miles from the terminus.

These silicon-iron alloy grounding poles are encased in concrete and connected with conductors that are supported about a meter above the ocean floor. The material used have been tested to withstand the highly corrosive sea water.

These systems never (IMO) ever need to be tested except of course in situation where intentional or accidental destruction of the structure.

It would be quite a job-- testing grounding rods while wearing diving equipment while tugging along a Megger.

(Credits for your insight.):thumbsup:
 
myspark said:
Not being flippant on most of what is being said, I think that it makes a lot of engineering sense to be able to determine the integrity of the grounding system on an ongoing basis.
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Why? Unless you are involved with high voltage I don't see any value at all.

Proactive steps to prevent premature failure sounds to me as an exercise of hindsight. Shouldn't it be more effective or unincumbered if during the planning stage, soil conditions that could affect the serviceability of say certain material that can withstand the corrosive attack of the material used for grounding rod be performed first?
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Do you have any idea what you are saying? Nobody else does. You just contradicted yourself at least four times in two sentences.
 
ActionDave said:
Why? Unless you are involved with high voltage I don't see any value at all.


Do you have any idea what you are saying? Nobody else does. You just contradicted yourself at least four times in two sentences.
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Cite exactly where the contradictions are and enumerate where those four occurrences are.
I'm responding to OP and I will continue to respond not to some one-liner statement.
Why don't you allow him to admonish me instead.
 
myspark said:
Proactive steps to prevent premature failure sounds to me as an exercise of hindsight.
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1, 2, 3
Shouldn't it be more effective or unincumbered if during the planning stage,
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4
soil conditions that could affect
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It's effect not affect.

the serviceability of say certain material that can withstand the corrosive attack of the material used for grounding rod be performed first?
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5
 
ActionDave said:
1, 2, 3

4

It's effect not affect.


5
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That did it. How could I be compelled to respond to your post when you can't tell the difference between a verb and an adjective. Perhaps a linguist can chime in to help?

Again tell OP (if he is willing) to rebut my statement.
 
myspark said:
That did it. How could I be compelled to respond to your post when you can't tell the difference between a verb and an adjective. Perhaps a linguist can chime in to help?
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affect- verb

effect- noun
Again tell OP (if he is willing) to rebut my statement.
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How about responding to my question about value of testing the integrity of a grounding system on an ongoing basis outside of a high voltage system.
 
ActionDave said:
affect- verb

effect- noun

How about responding to my question about value of testing the integrity of a grounding system on an ongoing basis outside of a high voltage system.
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I'm referring to your allusion on the usage of effect and effective.

None of the post specifically referred to low voltage but grounding as a whole.

I'll say it again, tell OP to respond. I'm not buying your fishing expedition by going to grammar instead of referring to technical aspects.

By the way, I have an accreditation in English along with my required teaching Math eligibility which I have done briefly when I was overseas.
 
Even with your perceived erroneous use of affect vs effect, the collocation is more sensible with my usage.

Where is the linguist's help to save the day?
 
ActionDave said:
Grounding ie earthing as a whole is overrated.
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So why would it be an issue if grounding applies to both low voltage and high voltage.
What's good for the goose is good for the gander.
In both cases the other ones relevance is relevant to the other and I don't think is overrated.

It just depends on how a person perceive it to be. Grounding is a part of the electrical trade. No overrating as such.
 
myspark said:
So why would it be an issue if grounding applies to both low voltage and high voltage.
What's good for the goose is good for the gander.
In both cases the other ones relevance is relevant to the other and I don't think is overrated.
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Biggest single difference is that at low voltage a ground connection alone will generally not let a line to ground fault trip OCPD, while at medium and high voltage it can and usually does.
 
GoldDigger said:
Biggest single difference is that at low voltage a ground connection alone will generally not let a line to ground fault trip OCPD, while at medium and high voltage it can and usually does.
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The gist of OP's post is about keeping the grounding structure to serve it's purpose and what impact has environment in keeping it fail safe.

How those protective devices would function in medium and high voltage in case of ground fault is irrelevant.

He did not mention it.

I'll say it again, I welcome OP's rebuttal.
 
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