The NEC vs. Engineers

[George Stolz]

Re: The NEC vs. Engineers

I think my mental issue is, the NEC states "that portion of the conductor that is the sole connection to the grounding electrode shall not be required to be larger than 6 AWG copper wire or 4 AWG aluminum wire" for a ground rod.

Inherent in that statement, signed into law by the AHJ, is essentially a guarantee to anyone governed by the NEC. That conductor shall not be required to be larger, by the governing auhority. So it leaves me a little confused:
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• <font size="2" face="Verdana, Helvetica, sans-serif">What mechanism exists in law or in code that can allow an AHJ to violate that section?</font>
• <font size="2" face="Verdana, Helvetica, sans-serif">Is there something binding in having plans approved, legally?</font>
• <font size="2" face="Verdana, Helvetica, sans-serif">A statement has been made that it takes an engineer to modify the plans. Plans are paper, ground rods and conductors are steel and copper. I don't change the plans when I ignore them. </font>

<font size="2" face="Verdana, Helvetica, sans-serif">
I agree with many of the statements made here, that the AHJ should inspect to code, and the engineer/customer/GC/private sector should ensure that contractual obligations are met.

The plan review process is confusing to me, and I feel the key is in that mud somewhere.

I appreciate all the replies, my hat's off to all the engineers who threw their view in.

Oh, and Lady: what's a "first" grounding electrode?

 

[physis]

Re: The NEC vs. Engineers

I misread larry's post Bob. I thought it was a different subject.

 

[charlie]

Re: The NEC vs. Engineers

George, if you are going to a ground rod and continue on to the water pipe (I don't have a clue why you would do it that way) then with a 400 ampere service, you would be required to run a 1/0 Cu GEC to the ground rod and then continue the 1/0 GEC to the water pipe. The ground rod is the first grounding electrode. If the water was first, then you would run 1/0 to the water and then #6 to the ground rod from the water. Lady was using first in the manner that the dictionary meant it to be used.

 

[George Stolz]

Re: The NEC vs. Engineers

Charlie, I didn't realize that the code spelled it out about just like she said! I assumed it was a hole in the code, not a prescribed method:

According to :

'02 250.64(F) To Electrode(s). A grounding electrode conductor shall be permitted to be run to any convenient grounding electrode available in the grounding electrode system or to one or more grounding electrode(s) individually. The grounding electrode conductor shall be sized for the largest grounding electrode conductor required among all the electrodes connected to it.

 

[physis]

Re: The NEC vs. Engineers

By Charlie:

Lady was using first in the manner that the dictionary meant it to be used.

Well that's uncalled for. How are you supposed to know what somebody's talking about.

 

[69boss302]

Re: The NEC vs. Engineers

You know, if we overanalize it enough we could come up with a book as big as the NEC just to find out what the dictionary term first really means.

 

[lady sparks lover]

Re: The NEC vs. Engineers

Originally posted by physis:

By Charlie:

Lady was using first in the manner that the dictionary meant it to be used.

 

[eprice]

Re: The NEC vs. Engineers

Originally posted by georgestolz:
I agree with many of the statements made here, that the AHJ should inspect to code, and the engineer/customer/GC/private sector should ensure that contractual obligations are met.

I'm not replying specifically to you George, it's just that your quote was the one I happened to pick

I agree that the idea expressed here is correct in many parts of the country. As an inspector it would make my job much easier if it were the case in Utah. However, to give some perspective to the discussion, here is an excerpt from the Utah Uniform Building Standards Act administrative rules:

R156-56-502. Unprofessional Conduct - Building Inspectors.
"Unprofessional conduct" includes:
.
.
.
(10) approval of work which materially varies from approved documents that have
been stamped by an architect, professional engineer or both unless authorized by the
licensed architect, professional engineer or both; and
.
.
.

In Utah it is unprofessional conduct for me to knowingly approve somthing that fails to meet the project plans or specs, even if it meets code.

 

[rbalex]

Re: The NEC vs. Engineers

On the project I'm currently on, one of the systems has gone well beyond "belt and suspenders" and is now into "bailing wire and duct tape," in my opinion. The engineer of record has failed to justify the design economically to my satisfaction; nevertheless, it is his design. I am also a PE and, in this case, definitely well qualified to comment on it.

I just did.

It goes in the way he designed it - no matter what my opinion is to the contrary.

 

[tomgreen1000]

Re: The NEC vs. Engineers

I am using 1999 NEC references here, not sure what is standard on this forum.

If you are in the City of Sacramento,
1. ground rods not allowed, you must have a ufer
2. see figure 250-26 in 1999 NEC handbook for GEC sizing.

My personal understanding is if the GEC went directly from the ufer to the bussing, then #4 CU would be maximum size, per 250-66(b). But as illustrated in figure 250-26 in handbook, if there is an exothermic weld or irreversible compression connection where multiple GEC are bonded, then the GEC from this bonding point to the bussing must be full sized per 250-66 (maximum of 3/0 copper). Since we have no idea how things will be installed in the field, we always show full size per 250-66 on our plans.

Tom

[ July 21, 2005, 06:34 PM: Message edited by: tomgreen1000 ]

 

[benaround]

Re: The NEC vs. Engineers

That is just Wrong!!

frank

 

[tomgreen1000]

Re: The NEC vs. Engineers

Frank, which are you referring to? The ground rods? Apparently it has been part of the city ordinances for many years. And it is a never ending source of complaint when out of the area contractors do jobs here.

If you are referring to our "oversizing" of the GEC, then please add some clarification. We have worked quite a few projects where remodels, additions, and numerous other things have caused the GEC to not be solely from ufer to bussing. Code is pretty clear that the portion of the GEC to the first grounding electrode must be full size per 250-66. When the inspector starts making you rip up finished work because of this, it only takes once for both contractor and engineer to decide that this "oversizing" can save you a big headache. Or you might be saving the guy in the future who works an expansion from the headache. It seems a small price to pay.

Maybe in your area, the inspectors/AHJ see this differently. But this is how it is done locally. I have seen work from numerous other engineers in this area and all of them are like this.

Tom

Edit to reword without using "continuous"

[ July 21, 2005, 08:29 PM: Message edited by: tomgreen1000 ]

 

[iwire]

Re: The NEC vs. Engineers

Originally posted by tomgreen1000:
Code is pretty clear that if the GEC is not continuous then it must be full size per 250-66.

Tom, what code is that?

 

[physis]

Re: The NEC vs. Engineers

By tomgreen1000:


If you are in the City of Sacramento,
1. ground rods not allowed, you must have a ufer

It could be worse. California government is very pushy. And often irrational. Sacramento being the capitol the AHJ is almost duty bound to add things to code that impose unnecessary burden. Sometimes I think it really is part of their thinking.

Edit: Added quote.

[ July 21, 2005, 07:46 PM: Message edited by: physis ]

 

[tomgreen1000]

Re: The NEC vs. Engineers

250-66 Size of AC GEC
The size of the GEC ... shall not be less than given in Table 250-66, except as permitted in (a) through (c).

250-66(b) Connections to Concrete-Encased Electrodes
Where the GEC is connected to a concrete-encased electrode ... that portion of the conductor that is the sole connection to the grounding electrode shall not be required to be larger than #4 copper wire.

So when the GEC is not soley a connection from ufer, it must be sized per 250-66. Again I refer to figure 250-26 in the 1999 NEC handbook for a perfect example. While this bonding of multiple GEC at a single point is not typical install practice, it has happened to me often enough that I always size the GEC per 250-66.

Tom

[ July 21, 2005, 07:55 PM: Message edited by: tomgreen1000 ]

 

[tomgreen1000]

Re: The NEC vs. Engineers

Physis, it can always be worse can't it?

They City of Folsom, CA does not allow you to use the rebar for the ufer. You must have a continuous length of at least 20 feet of #4 bare copper in the footing/foundation.

Tom

 

[iwire]

Re: The NEC vs. Engineers

Originally posted by tomgreen1000:
So when the GEC is not soley a connection from ufer, it must be sized per 250-66.

That is not the same thing as being continuous.

I can run a full size GEC to the water pipe than drop down to 4 AWG from the water pipe to the uffer, than I could drop down to 6 AWG from the uffer to a rod (if you could use one.)

 

[physis]

Re: The NEC vs. Engineers

They City of Folsom, CA does not allow you to use the rebar for the ufer. You must have a continuous length of at least 20 feet of #4 bare copper in the footing/foundation.

Folsom is very close to ground zero. I'm sure there's plenty of fall out.

 

[tomgreen1000]

Re: The NEC vs. Engineers

Iwire, I agree completely. If anyone proposed your scenario I would absolutely approve it.

You are also correct about my use of the word "continuous". A previous post used the term "first" point of connection which might be more clear. I am not sure how to word the post correctly. I will edit the post, if you can help me reword it. I stand by my contention that there are many cases where the GEC needs to be sized per 250-66. And when you are preparing plans there is no way to know which portions of which GEC will be where. The "oversized" GEC is overkill, but I do not see a simple solution.

Tom

 

[lady sparks lover]

Re: The NEC vs. Engineers

Originally posted by iwire:

Originally posted by tomgreen1000:
So when the GEC is not soley a connection from ufer, it must be sized per 250-66.

That is not the same thing as being continuous.

I can run a full size GEC to the water pipe than drop down to 4 AWG from the water pipe to the uffer, than I could drop down to 6 AWG from the uffer to a rod (if you could use one.)

I was referring to that as well. This is how I understood it to be. For the main connection to the grounding electrode, the size must be by 250-66, all those there after can be (a)-(c). Ok..good, I don't need that straight jacket!