Single Grounding Electrode

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Where only one grounding electrode is used.

250.52 lists the electrodes permitted for grounding. I have noticed that some inspectors are saying that the electrician has to use a concrete encased electrode.

1. They site 250.50. Doesn't that only pertain to to bonding where there is more than one grounding electrode?

2. If a concrete encased electrode is require to be used in all cases where it possible to install one why is it just listed with the other grounding electrodes permitted in 250.52?

250.30(A)(7) states that you must use a water pipe or structural metal but if they aren't there you can use one of the others.

3. Why doesn't the code state that a concrete encased electode is required and if not possible you can use the others that are permitted?

4. If all of the different types of grounding electrodes are acceptable why can't the electrician decide which one they use?

It is clear as mud but it covers the ground and the confusion make my head go round.

Hope this isn't too much for my first post and question.

Thanks for your help in advance.
 
If the electrodes are 'present' you must use them.

When the cement guys formed the footing if they used more then 20' of connected 1/2" or larger re-bar then the concrete encased electrode is present and the electrician must use it.

This is no different then a metal water pipe.

If the plumber installs a metal under ground water pipe that is in contact with the earth for more then 10' the water pipe electrode is present and the electrician must use it.

If the plumber installs a plastic main the electrician does not have to worry about.

Likewise if the cement guys don't use any re-bar the electrician does not have to worry about it.
 
There are likely any of three electrode that are usually present. The water pipe, the CEE and building steel. If any of these exist you must use them. If none of them exist you can make one of the others on the list in 250.52, the ground ring, rod or pipe, plate or other local metal underground system or structure.
 
Friendly said:
Where only one grounding electrode is used.

250.52 lists the electrodes permitted for grounding. I have noticed that some inspectors are saying that the electrician has to use a concrete encased electrode.

1. They site 250.50. Doesn't that only pertain to to bonding where there is more than one grounding electrode?

2. If a concrete encased electrode is require to be used in all cases where it possible to install one why is it just listed with the other grounding electrodes permitted in 250.52?

250.30(A)(7) states that you must use a water pipe or structural metal but if they aren't there you can use one of the others.

3. Why doesn't the code state that a concrete encased electode is required and if not possible you can use the others that are permitted?

4. If all of the different types of grounding electrodes are acceptable why can't the electrician decide which one they use?

It is clear as mud but it covers the ground and the confusion make my head go round.

Hope this isn't too much for my first post and question.

Thanks for your help in advance.
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Greetings,
In item (2) I think you meant to say 250.52(A)(7), but your point is well taken. I don't think that the code requires what the inspector is asking for, if no concrete encased electrode is present. Even if it is present and the other conditions for it are not met (rebars and their size, tie wire, etc.), I think it is still a moot point as far as the code is concerned. . e/m.
 
Energy-Miser said:
Greetings,
In item (2) I think you meant to say 250.52(A)(7), but your point is well taken. I don't think that the code requires what the inspector is asking for, if no concrete encased electrode is present. Even if it is present and the other conditions for it are not met (rebars and their size, tie wire, etc.), I think it is still a moot point as far as the code is concerned. . e/m.
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Well e/m, It might not be moot if the incoming water supply uses plastic pipe. Then the UFER is required prior to foundation pour unless the local authority says otherwise. The question arises, what water pipe is going to be installed, copper or pex?
I would not wait to find out, its cheaper and easier to stub up from a wire tied footer rebar rather than get blind-sided with being required to furnish two grounding rods, clamps, and extra lengths of copper GEC awg. rbj
 
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gndrod said:
Well e/m, It might not be moot if the incoming water supply uses plastic pipe. Then the UFER is required prior to foundation pour unless the local authority says otherwise. rbj
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The NEC does not require that either of these be installed.
 
iwire said:
If the plumber installs a plastic main the electrician does not have to worry about.
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I would just like to clarify that there must still be a bond to the water pipes if they are metallic even if the underground main is plastic.
 
Dennis Alwon said:
I would just like to clarify that there must still be a bond to the water pipes if they are metallic even if the underground main is plastic.
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Agreed, but the real issue in residential is, what electrode is available for connecting the GEC? The point being, it is much cheaper and less time consuming to hook-up a rebar UFER rather than pounding rods.
 
gndrod said:
Agreed, but the real issue in residential is, what electrode is available for connecting the GEC? The point being, it is much cheaper and less time consuming to hook-up a rebar UFER rather than pounding rods.
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That may be true but you are suppose to use the CEE. There should be no choice between pounding ground rods and the CEE. If the CEE is present then case closed-- you must use it. If you want to drive rods also you can but you don't have to.

Basically new building must use the CEE-- fact is most inspectors still think you can do either the CEE or the rods. That is not the case by NEC rule.
 
Dennis Alwon said:
Basically new building must use the CEE-- fact is most inspectors still think you can do either the CEE or the rods. That is not the case by NEC rule.
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That answer assumes there is qualifying steel in the footer.

No all areas have that steel in the footing. :smile:
 
gndrod said:
Bob, You're right, so what would you do in a residential install?
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Assuming there was no steel I would probably pound two rods and move on.

Assuming there is no steel the EC would likely not have even been chosen while the footing is being done.

That said, if there was steel in the footing I would not get a choice but the GC had better have brought an EC in for installation and inspection of the electrode before the pour.
 
iwire said:
That answer assumes there is qualifying steel in the footer.

No all areas have that steel in the footing. :smile:
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I realize that but I thought that was understood from your post. I started typing that and was trying to keep it short and be clear--- I did neither.
 
iwire said:
That answer assumes there is qualifying steel in the footer.

No all areas have that steel in the footing. :smile:
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Bob, It could be a pole house, but I am interested in what you would do on a resi project.
 
Dennis Alwon said:
If there is no steel you could still put 20 feet of #4 copper in the footer in lieu of ground rods.
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Of course, no one has said otherwise.

Heck you can wrap the house with a 4/0 bare ground ring if you want. :)

But we are not required to do either.

If no electrodes 'are present' then add two rods and walk away.
 
iwire said:
Of course, no one has said otherwise.

Heck you can wrap the house with a 4/0 bare ground ring if you want. :)

But we are not required to do either.

If no electrodes 'are present' then add two rods and walk away.
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I guess I missed your answer on post 14. Good answer.
 
Single Grounding Electrode

Dennis Alwon said:
That may be true but you are suppose to use the CEE. There should be no choice between pounding ground rods and the CEE. If the CEE is present then case closed-- you must use it. If you want to drive rods also you can but you don't have to.

Basically new building must use the CEE-- fact is most inspectors still think you can do either the CEE or the rods. That is not the case by NEC rule.
Click to expand...

I totally agree, if present the cee must be used.
 
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