CEE Rebar Stub Out? I don't think so.

[crossman]

If the intent was that the connection be embedded it would not be in a 'permissible' wording in the exception - it would be required in the code.

The way that 250.68 is worded makes perfect sense as it is. In general, the GEC connection to the electrode needs to be accessible. But then in the exception they make it clear that certain types of electrodes will have an encased or buried connection. I don't know how that could be any clearer.

Remember that the NEC is not a design manual....

Correct. 2008 NEC 90.1(C)

 

[mivey]

Now go back and look, there are many who agree with croosman and myself.

I guess I'm one of the kool-aid drinkers. I have already declared iwire the technical winner in post #111. Y'all better recognize.:grin:

Since charlie b was not here to diagram a sentence this time (see #85 of George's link in #131), it is all over.

You just can't get away from crossman's #175.

 

[crossman]

I read the entire thread that George Stolz linked to. That one was back from 2005 when they first changed the "available" to "present". It was an interesting read.

I was surprised that I had to disagree with charlie b's reading of 250.52(A)(1) concerning what a metal underground water pipe electrode consists of. I have been debating starting a new thread on that.

But be careful, Mivey, because that kool-aid that Iwire is so freely giving is laced with PoiSoN!

 

[iwire]

And I do not think I am alone either

I did not mean to imply you where, but you did make it sound like I was out on my own here.

- would you say that the code is subject to interpetation? I can run SEC ~40' into a building, can you?

We all know that section was left intentionally vague for the AHJs to work out.

Because you think you are right does not make it so in this situation, and promoting the idea that you are with your very respected position on this and many other forums will still not make you RIGHT - just opinionated.....

I stand by my highly opinionated opinion. :grin:

thankfully all of them are not drinking the same cool-aid,

Why are you so worried about that?

Lets just say I happen to be right here. (Pretend OK?):smile:


What would that mean, why would that be bad?

Maybe the best answer is a mandatory copper electrode in the footing.

coming here to get poisoned by your opinion that you spout as absolute truth.... :grin:

:grin:

This is the truth

250.62 prohibits using steel as a GEC.

250.52(A)(3) says the concrete encased electrode is encased in concrete.

No one should take my word for it they can read t for themselves.

Still like to here an answer to this :smile:

Okay all you stubber-uppers, answer Iwire's question. How far can you run the stub-up? Give me a code section to support your answer.

Because, if the stub-up is good according to code, then there is nothing to stop me from extending the stub-up with some rebar and tie-wire, for example, 200 feet to the service. Heck, I could even run the rebar up inside a wall, into a ceiling cavity, turn horizontal and run a couple hundred feet with sections of rebar tie-wired together, and then take it to the service.

What code section would stop me?

 

[e57]

The way that 250.68 is worded makes perfect sense as it is. In general, the GEC connection to the electrode needs to be accessible. But then in the exception they make it clear that certain types of electrodes will have an encased or buried connection. I don't know how that could be any clearer.

Change that to "CAN HAVE" and I will agree to that - in fact it has only been recently (year or so.) that clamps rated for concrete encasement from copper to steel have been available here. (Not sure about your location....)

 

[e57]

I did not mean to imply you where, but you did make it sound like I was out on my own here.

No there are many in your camp, and I have not counted those in the camp that I would support.

I stand by my highly opinionated opinion. :grin:

So do I stand by my own

Maybe the best answer is a mandatory copper electrode in the footing.

Maybe it is....:smile:

 

[crossman]

in fact it has only been recently (year or so.) that clamps rated for concrete encasement from copper to steel have been available here.

This has absolutely no bearing on what 250.52(A)(3) literally means. The AHJ can interpret it however they like. But that also has nothing to do with what the section literally means.

 

[paul]

250.52(A)(3) says the concrete encased electrode is encased in concrete.

The code definition of Grounding Electrode, A device that establishes an electrical connection to earth. This bar, also a CEE, extended and bent up and out of the footing does just that, while still being encased for 20' by 2" of concrete. Nowhere does it say that it cannot emerge from the concrete in the definition. Therefore, I dissent from Bob's view on the subject and don't agree that it needs any clarification by the code writers.

 

[e57]

The code definition of Grounding Electrode, A device that establishes an electrical connection to earth. This bar, also a CEE, extended and bent up and out of the footing does just that, while still being encased for 20' by 2" of concrete. Nowhere does it say that it cannot emerge from the concrete in the definition. Therefore, I dissent from Bob's view on the subject and don't agree that it needs any clarification by the code writers.

Well put Paul! But I do think it does need some clarification - otherwise we would not be on page 7 of this topic saying the same thing to persons who are absolutely convinced otherwise.

 

[e57]

This has absolutely no bearing on what 250.52(A)(3) literally means. The AHJ can interpret it however they like. But that also has nothing to do with what the section literally means.

In both camps of thinking on the topic - both are right literally - then on the other hand - one is right figuratively, and the other is (well) wrong because in context of the rest of 250 there are contradictions to the arguments made.

 

[Minuteman]

Well put Paul! But I do think it does need some clarification - otherwise we would not be on page 7 of this topic saying the same thing to persons who are absolutely convinced otherwise.

I agree with e57 and Paul and have stayed out of this debate up to this point as I believe there are those times when the CMP has done their best to make something clear, and it still is worded were it can be misconstrued.

Here is some interesting reading about the Ufer Ground.

 

[e57]

Some reading on Mr. Ufer is in order:
http://www.psihq.com/iread/ufergrnd.htm
http://www.mikeholt.com/files/PDF/Use_of_Conc_Encased_GR_as_GE_Fagan_Lee_1970.pdf
http://www.iaei.org/subscriber/magazine/01_d/johnston.htm

 

[crossman]

There are no semantics are misinterpretations here.

According to 2008 NEC 250.52(A)(3):

A concrete-encased electrode made from rebar has the following requirements. All this is taken directly from the 2008 NEC -- a rebar CEE must meet ALL 6 of the following requirements.

1. must be encased by at least 2 inches of concrete
2. must be located horizontally near the bottom, or veritcially
3. must be within that portion of the foundation or footing that is in direct contact with earth
4. must consist of at least 20 feet of one or more rebars
5. must be bare or zinc galvanized or otherwise conductively coated steel bars
6. must be not less than 1/2 inch diameter

A rebar stub-up does not meet #1 and #3 and therefore is not a part of the electrode according the the National Electrical Code, 2008 edition. This leads to violations of other sections in Article 250 when the stub-up is used as a connection the the CEE.

I just don't know how it can be interpreted any other way.

 

[crossman]

I believe there are those times when the CMP has done their best to make something clear, and it still is worded were it can be misconstrued.

No doubt! There is a certain amount of pleasure in picking apart the literal meaning of the text in the NEC. You may as well join in on the fun. Don't be shy.

 

[crossman]

The code definition of Grounding Electrode, A device that establishes an electrical connection to earth. This bar, also a CEE, extended and bent up and out of the footing does just that, while still being encased for 20' by 2" of concrete. Nowhere does it say that it cannot emerge from the concrete in the definition. Therefore, I dissent from Bob's view on the subject and don't agree that it needs any clarification by the code writers.

Paul, you make a good point here. If I was going solely by the definition in Article 100, it would seem that the rebar stub-up would be okay. The stub-up is part of the device that establishes the connection to earth. But then 250.52(A)(3) confuses the issue by giving a precise set of requirments that a CEE must meet, and a stub-up cannot meet all the requirements as evidenced in a recent post of mine.

Also, the definition of grounding electrode has changed in the 2008 Code.

 

[e57]

Now lets dicuss the merits of the Ufer Ground

Larger surface area as concrete is conductive - and according to that second article I linked to, so is tie wire (I believe they used the word "surpising"), and all of the steel. So all of the rebar in the foundation is conductive path - and so is all of the concrete - thats how this whole thing works.... The whole thing is the electrode - not just the rebar at the bottom - all of it.

Mr. Ufers original tests were done on slabs with cellular footings and grade beams - as all of the mass was conductive he got a really low ohm value in most measurements - and he published studies to that effect. Those were read by people, and eventually made it into the code - and only recently in the broad scope of NEC history.

Ufer also came up with the 20' of #4 copper at the bottom - because he felt it worked best, and it found its way into the code in '68. But engineers who have studied his findings also know that the rebar is part of the whole mass - and that concrete that is the actual connection to earth is difficult to get a reliable connection to - and added that a connection to the rebar would also be suitable in '75. Some others noted that one could do the same in a concrete pier, and the vertical ufer was born in '08. Some more history, and more about that can be found here.

(Duh - found more paper on the topic)

Anyway - my point is that the rebar stub-up is a convienent way to connect to the mass of concrete, steel and earth below - it is not a GEC to some figurative electrode in the concrete - it is a part of the electrode as a whole. Even an achor bolt tie-wired to some of the rebar in the foundation could "electrically" the used as a connection - although not in the code - YET! As for stubbed rebar - Use it or not... But be carefull in what you "teach" others on the concept, as what you say as an opinion can spread like a plague - and become that persons interpetion of the concept as a whole. And what is written in the code as a standard is not the whole concept.

 

[e57]

a rebar CEE must meet ALL 6 of the following requirements.


I just don't know how it can be interpreted any other way.

By not implying that the above is in the code - as it is not, or it would have been written in that manner.... And that #1 on your list is in direct conflict with 250.68 and somehow in your mind - the accessible portion of the electrode does not comply when the same continuous metal at the other end does.

 

[e57]

and a stub-up cannot meet all the requirements as evidenced in a recent post of mine.

You really need to stop using 'yourself' as evidence to the answers here. I love a good debate but need a broader scope of reference for the argument. :roll:

 

[iwire]

The code definition of Grounding Electrode, A device that establishes an electrical connection to earth.

That is like saying the Article 100 definition of 'outlet' means that a receptacle and a lighting outlet are exactly the same.

Electrode is a general term, concrete encased electrode is a specific term describing an electrode installed in a specific way.

 

[iwire]

Here is some interesting reading about the Ufer Ground.

Some reading on Mr. Ufer is in order:
http://www.psihq.com/iread/ufergrnd.htm
http://www.mikeholt.com/files/PDF/Use_of_Conc_Encased_GR_as_GE_Fagan_Lee_1970.pdf
http://www.iaei.org/subscriber/magazine/01_d/johnston.htm

The point here? :smile:

I know I am aware of the history of the Ufer but it is irreverent. :smile: We are talking about what the NEC requires not what we like, not what Mr uffer envisioned, not what Mr Uffer had for breakfast. :smile: