Ufer ground

[jwelectric]

Re: Ufer ground

I was just debating weather the rebar is required over the #4 copper.

I don?t see any wording that would make me believe that if both were present that the rebar would take precedence over the #4.

It is clear by the wording that either OR would constitute the concrete encased electrode.

 

[jwelectric]

Re: Ufer ground

Originally posted by Volt102
Why not just put 20' of copper in the footing. You need to use the concrete encased electrode because you have rebar in the footing. If you put the 20' of copper in the concrete it would satisfy 250.52(A)(3) wouldn't it?

Jim

Originally posted by don_resqcapt19
I don't think so. The rebar is still in the footing and is still a required grounding electrode. It is my opinion that if you put 20' of #4 copper in the footing, that the rebar must be bonded to the #4.
Don

Originally posted by Roger
note the first two words in 250.52(A)(3) "An electrode" which is singular.

After you have bonded to one you have satisfied the code.

I would also point out that 250.52(A)(5)and(6)
are plural, and if numerous Concrete-Encased Electrodes were intended to be used if available, (3) should have been written to reflect plural.

Roger

Here I must agree with Roger that 250.52 (A)(3) is asking for a singular electrode and it would be to the choosing of the installer to which is chosen the rebar or the #4 cooper.


Edited to get the quote and bold codes entered correctly
I love it when I learn new things


[ August 11, 2005, 08:18 AM: Message edited by: jwelectric ]

 

[georgeswe]

Re: Ufer ground

a lil off the subject what does "UFER" stand for ??

 

[petersonra]

Re: Ufer ground

Originally posted by georgeswe:
a lil off the subject what does "UFER" stand for ??

I think it was someone's last name that did some reseacrh in this area a number of years ago.

 

[don_resqcapt19]

Re: Ufer ground

I'm going to stick to my opinion that if you add the #4 copper, you still have to bond to the rebar.

250.50 Grounding Electrode System.
If available on the premises at each building or structure served, each item in 250.52(A)(1) through (A)(6) shall be bonded together to form the grounding electrode system. Where none of these electrodes are available, one or more of the electrodes specified in 250.52(A)(4) through (A)(7) shall be installed and used.

The rebar is an "item" and the #4 copper is a different "item".
Don

 

[jwelectric]

Re: Ufer ground

Originally posted by don_resqcapt19:
I'm going to stick to my opinion that if you add the #4 copper, you still have to bond to the rebar.

250.50 Grounding Electrode System.
If available on the premises at each building or structure served, each item in 250.52(A)(1) through (A)(6) shall be bonded together to form the grounding electrode system. Where none of these electrodes are available, one or more of the electrodes specified in 250.52(A)(4) through (A)(7) shall be installed and used.

The rebar is an "item" and the #4 copper is a different "item".
Don

I also agree that each item in 250.52(A)(1) through (A)(6) shall be bonded But I question just what is (A)(3).

Why do you believe that the rebar is required to be used and the #4 is not? Where do you find wording to substantiate that only the rebar is required?

Here is the wording found in (A)(3)

(3) Concrete-Encased Electrode. An electrode encased by at least 50 mm (2 in.) of concrete, located within and near the bottom of a concrete foundation or footing that is in direct contact with the earth, consisting of at least 6.0 m (20 ft) of one or more bare or zinc galvanized or other electrically conductive coated steel reinforcing bars or rods of not less than 13 mm (? in.) in diameter , or consisting of at least 6.0 m (20 ft) of bare copper conductor not smaller than 4 AWG. Reinforcing bars shall be permitted to be bonded together by the usual steel tie wires or other effective means.

Notice the comma and the word OR that I have highlighted in bold, the comma stops one thought and begins another. The word OR give a choice between the two thoughts.
(A)(3) is titled Concrete-Encased Electrode not concrete-encased rebar. Either one of the two is a Concrete-Encased Electrode and one is as good as the other.


[ August 11, 2005, 01:55 PM: Message edited by: jwelectric ]

 

[eprice]

Re: Ufer ground

I am with Don on this one. Does the rebar meet the definition of a concrete encased electrode? Is it present (2005 language) at the building? If the answer to both of these questions is yes, then 250.50 requires it to be used as an electrode. If you add 20 feet of copper in the footing, then the copper meets the definition of a concrete encased electrode and must be used also. Since you have to use both of these electrodes, the easiest way to do so with one GEC is to bond the two together.

 

[jwelectric]

Re: Ufer ground

Originally posted by eprice:
I am with Don on this one. Does the rebar meet the definition of a concrete encased electrode? Is it present (2005 language) at the building? If the answer to both of these questions is yes, then 250.50 requires it to be used as an electrode. If you add 20 feet of copper in the footing, then the copper meets the definition of a concrete encased electrode and must be used also. Since you have to use both of these electrodes, the easiest way to do so with one GEC is to bond the two together.

So what you are saying is that if no other electrode is present then I am required to install a rod and a pipe electrode as outlined in 250.52 (A)(5) Rod and Pipe Electrodes

The same thing is being said in (A)(3) that is being said in (A)(5) either or not both.

Read 250.52 (A)(3) and see if the word OR is not present.

 

[eprice]

Re: Ufer ground

Originally posted by jwelectric:
So what you are saying is that if no other electrode is present then I am required to install a rod and a pipe electrode as outlined in 250.52 (A)(5) Rod and Pipe Electrodes

The same thing is being said in (A)(3) that is being said in (A)(5) either or not both.

Read 250.52 (A)(3) and see if the word OR is not present.

No, you are not required to install more than one electrode. If the rebar were not present in the footing (and in some parts of the country this may happen) you could install a copper wire in the footing and use just that one electrode. Or you could drive a ground rod and use that electrode. But if the rebar is present, you must use it. You can't install the copper wire and ignore the presence of the rebar any more than you could install the copper wire and ignore the presence of a metal underground water pipe that was also present at the building.

 

[roger]

Re: Ufer ground

A Concrete-Encased Electrode is one item period. Which type is irrelevant as long as a Concrete-Encased Electrode as defined in 250.52(A)(3) is used if it is available.

JW's explanation of the punctuation used is cut and dry unless we change the rules of writing, and how I know we try to at times )

Roger

 

[volt102]

Re: Ufer ground

I understand that most of us in here would bond the rebar. Why not? It can only help right? The word UFER comes from Herb Ufer, an Army consultant from the 50's.

It is in my opion that the rebar should get bonded, but as an inspector, I would have to pass the installation as the book is worded if someone just installs the 20 feet of copper.

Maybe someone can put a change in for clarification?

Jim

 

[don_resqcapt19]

Re: Ufer ground

jw,

Why do you believe that the rebar is required to be used and the #4 is not? Where do you find wording to substantiate that only the rebar is required?

Because of these words from 250.50..."If available on the premises". The #4 copper is not available unless the EC installs it. There is no requirement to provide these electrodes. If there are no electrodes available, then the EC must provide one of the ones listed in 250.52(A)4 through (A)7.

 

[physis]

Re: Ufer ground

It is in my opion that the rebar should get bonded, but as an inspector, I would have to pass the installation as the book is worded if someone just installs the 20 feet of copper.

I've only looked in on this one from time to time. If I'm just repeating something already said I apologise.

What is important in my mind is first:

If the footing qualifies it be used.

Second, in response to the above quote:

I don't see any importance to bonding the rebar. What is important is that if the footing does have to be used that however it is connected needs to meet the requirements in 250.52(A)(3).

In other words, the rebar being there might cause the footing to be required as an electrode. But the rebar doesn't have to be used if something else is used in it's place so that the footing still qualifies.

And I think that is what is intended.

 

[roger]

Re: Ufer ground

For sake of conversation, let's say the design specifically calls for the EC to provide the #4 for the Concrete-Encased Electrode, (probably because the EE is lurking and has a twisted sense of humor) when we bond to this we have met the requirement.

For the record, IMO, The rod requirement for 25 ohms or add another rod is simply wasted resources and energy, however, with the other GE's, I think the more you can bond together, the better.

This doesn't change my opinion of the NEC requirement though.

Edited to correct some twisted spelling

Roger

[ August 11, 2005, 08:02 PM: Message edited by: roger ]

 

[jwelectric]

Re: Ufer ground

Well the first thing that needs to be addressed here is which cycle that is being quoted. I don?t think that we are to take part of one cycle and part of another cycle and make our own code.

2002
250.50 Grounding Electrode System.
If available on the premises at each building or structure served, each item in 250.52(A)(1) through (A)(6) shall be bonded together to form the grounding electrode system. Where none of these electrodes are available, one or more of the electrodes specified in 250.52(A)(4) through (A)(7) shall be installed and used.

2005
250.50 Grounding Electrode System.
All grounding electrodes as described in 250.52(A)(1) through (A)(6) that are present at each building or structure served shall be bonded together to form the grounding electrode system. Where none of these grounding electrodes exist, one or more of the grounding electrodes specified in 250.52(A)(4) through (A)(7) shall be installed and used.

In the 2002 cycle we didn?t need to do anything and there was no questions about the rebar due to the first two words, ?If available?
If the rebar was already covered by the concrete when the electrician got to the job then the rebar would not be available.

In the 2005 cycle the words was changed to, ?All grounding electrodes as described in 250.52(A)(1) through (A)(6) that are present?
Here a lot of people jumped the gun and said that the rebar was now required to be part of the electrode system.
This is not what is said, what that is said is the electrodes SPECIFIED in (A)(1) through (A)(6) that are present.
Now when I look at (A)(3) I see Concrete-Encased Electrode and it tells me that 20 foot of #4 will fulfill this requirement.

I am not required to bond the rebar if I install 20 feet of #4 bare copper. This bare copper will fulfill the requirement of the Concrete-Encased Electrode outlined in 250.52 (A)(3)

Don with due respect the words that you have quoted ?If available on the premises" are from the wrong code cycle.

 

[don_resqcapt19]

Re: Ufer ground

jw,
I don't have an electronic version of the 2005 code and I am not going to type code quotes. The wording change between 2002 and 2005 has no effect on my opinion of what the section says. 250.50 (2005)says that we have to use all that are present, as opposed to available(2002). The only reason for this change was to require the use of the rebar in a footing as a grounding electrode for new construction. 250.52 tells us what an electrode is, it does not give us a choice on using it if it is present. The "or" in 250.53(A)(3) only tells us that there are two types of concrete encased electrodes. This has no effect on the requirement in 250.50 that says you must bond all electrodes that are present.
I find it very interesting that 250.50 says that where none of the electrodes listed in 250.52(A)(1) through (A)(6) are present, that you must provide one or more of the types listed in (A)(4) through (A)(7). The concrete encased electrode is not in that list.
Don

 

[physis]

Re: Ufer ground

I find it very interesting that 250.50 says that where none of the electrodes listed in 250.52(A)(1) through (A)(6) are present, that you must provide one or more of the types listed in (A)(4) through (A)(7). The concrete encased electrode is not in that list.

But if I put an encased electrode in , it would be present.

I don't know if this only sounds funny to me right now but I can't stop laghing about it.

 

[jwelectric]

Re: Ufer ground

Originally posted by don_resqcapt19
The only reason for this change was to require the use of the rebar in a footing as a grounding electrode for new construction. 250.52 tells us what an electrode is, it does not give us a choice on using it if it is present. The "or" in 250.53(A)(3) only tells us that there are two types of concrete encased electrodes. This has no effect on the requirement in 250.50 that says you must bond all electrodes that are present.

As outlined above in 250.50 it states that, All grounding electrodes as described in 250.52(A)(1) through (A)(6) that are present

I fail to see any mention of rebar at this point. All I see is the referral to (A)(3) if it is present it shall be bonded together.

When I look at (A)(3) I see the title of, Concrete-Encased Electrode.
As I read through this section I see that there are two types listed as you pointed out above.

I fail to see any where in (A)(3) where I am told that if the rebar is present it MUST be used. All is see is the description of the two types.

250.50 tells me that if (A)(3) (a concrete encased electrode) is present it shall be bonded to the electrode system. After reading both sections I still can not see where I am told that I must bond any rebar of any kind to the electrode system unless I do not have the #4 in the footing and rebar is present.

Please point out where you are finding the words that mandates the rebar must be bonded if present.

I have done a little research on this and here is what I have found.

5-115 Log #1559 NEC-P05 (250-50)
Submitter: Michael J. Johnston, Int?l Assn. of Electrical Inspectors

Comments from the panel

BRETT: This proposal should have been accepted. The concrete encased electrode is proven to be an effective grounding electrode. By deleting "if available" it more clearly states the intention of the section that all electrodes be utilized to form an effective grounding electrode system. Many jurisdictions now amend this section of the NEC by deleting these words. The jurisdiction where I live does require the concrete encased electrode and it does not create an enforcement problem. Changes made by the code committees with less substantiation each code cycle always create some enforcement problems until the installers know the requirements being enforced. This proposal should be accepted.

JOHNSTON: The word available as used in this section is creating inconsistencies in the field relative to which grounding electrodes are required to be used in electrical installations. The concrete encased grounding electrode is a proven effective electrode and is inherent to the construction of most buildings or structures and should be included in the grounding electrode system as such. The NEC style manual recommends not using the word "available" to avoid this very type of inconsistency in application and enforcement Code rules.

Notice how the words concrete encased electrode is mentioned and no where does any one point to mandating that the rebar must be used.

 

[George Stolz]

Re: Ufer ground

Originally posted by don_resqcapt19:
This has no effect on the requirement in 250.50 that says you must bond all electrodes that are present.

My thought: In our hypotheticals, we are assuming the "electrode" is the metal in the concrete.

If the concrete is the electrode, then the rebar may be present in the concrete, but if we have connnected to the concrete in a different compliant manner, who cares about the rebar?

There are not two electrodes present: There is one body of concrete, and it has been connected to. (A)(3) is satisfied.

Side note: Of course, we're ignoring the greater potential advantages of using the rebar for this argument: Connecting remote electrodes, and overall better performance.

 

[iwire]

Re: Ufer ground

Isn't the concrete footing the electrode, not the rebar or the bare copper contained within?

In my mind the electrode is the portion that contacts the earth.

If in fact the concrete footing is the electrode then once it is connected by either the rebar or bare copper our job is complete.