Grounding Rod On New Construction

A.W.Davis

Hopefully some of the new construction guys who do foundations can give me guidance on this. I know the electricians know this one!!

I've got a homeowner who wants me to place a bid on doing all of the electrical on a detached 4 bedroom 1 bath guest house, I am 99% confident on doing all of the electrical, the only thing that is new to me (I mainly remodel) is the bonding..... can I attach a #4 ground wire with a bonding clamp to the rebar before the concrete pour, or do I have the foundation guys just 90 a piece of rebar out of the slab where my service panel is going to be located?

A.W.Davis

........anyone?

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A.W. Davis Construction Co.
http://www.awdavisconstruction.com/
Your friendly remodeling contractor

rabbitgun

Takes A Stab....................

Judging from your question I would need to write a treatise on grounding and bonding per the NEC to properly answer it. For one thing you seem to me to be confusing a concrete encased electrode with a rod electrode. And, metal underground gas pipe is not permitted to be grounded but above ground and in the building needs to be bonded in some cases.

A.W.Davis

Your right....I am confused(for now), grounding and bonding are new to me, and I want to expand my knowledge, and determine if I am capable of taking on this task properly before I place my bid with the homeowner. I just want to do everything right.

Whats the difference between the two (concrete encased electrode, and rod electrod)?

Sounds like my NEC book will have more info on this also.

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A.W. Davis Construction Co.
http://www.awdavisconstruction.com/
Your friendly remodeling contractor

Glasshousebltr

Not real sure, my methods on the matter are a bit controversial, but I think bonding and grounding are issues dealing with wives and kids.

Bob

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Bob

rabbitgun

Ah ha! you have a copy of the NEC. That's good, start at 250.50 and read through 250.104 to get your mind around grounding and bonding. 05 NEC that is.

A.W.Davis

word

__________________
A.W. Davis Construction Co.
http://www.awdavisconstruction.com/
Your friendly remodeling contractor

A.W.Davis

Will do thanks.....time to bury my nose in a book.

__________________
A.W. Davis Construction Co.
http://www.awdavisconstruction.com/
Your friendly remodeling contractor

CE1

This would do just fine.
Extended Reading Requirement:
Attachment 3495

A.W.Davis

Thanks man........more info, much appreciated.

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A.W. Davis Construction Co.
http://www.awdavisconstruction.com/
Your friendly remodeling contractor

Sparky Joe

On a new building the ufer ground is required, so tie your number 4 to the steel and don't rely on the conrete guys to do it for you, chances are they won't and then it's set in stone and you're chipping out concrete. Your water line is the only other thing required after the 'concrete encased electrode' (and bulding steel if there is any), no ground rods.

RobertWilber

Joe
sounds like you do this on occasion
Does that require a Cadweld joint if it is buried in concrete?

mahlere

nope. bridgeport (and other manufacturers) made a nice UL listed bolted clamp for the purpose.

Sparky Joe

No, they make a rebar clamp.

And it only needs to be irreversible if it's exposed, or something like that I don't remember.

A.W.Davis

Great info,thanks guys.!!

One more question for the wise out there.....can I enlarge an existing service panel knockout hole to accept 2" or 2 1/2" conduit....or is that a code violation?

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A.W. Davis Construction Co.
http://www.awdavisconstruction.com/
Your friendly remodeling contractor

CE1

You sure can. Just make sure that you have clearance in the panel to do it. If it is metal conduit make sure you use a grounding bushing. If it PVC pipe there is no need for a grounding bushing(but it looks good if you use a plastic bushing on the conduit connector). Also do not do this when any part on the panel is hot.

Carry On

A.W.Davis

10-4 thanks for the info!

__________________
A.W. Davis Construction Co.
http://www.awdavisconstruction.com/
Your friendly remodeling contractor

RobertWilber

I read that Ufer ground paper.
Really interesting
BTW it says that the conductor connection can NOT be in the concrete if it is a copper conductor

Speedy Petey

There are a few erroneous "facts" in that paper.
He states:
"If Ufer grounding alone was enough, the manufacturers of ground rods would go out of business. But a Ufer ground alone it is not adequate."
This is not so at all. The 2005 NEC is quite clear that a ufer alone is adequate if there is no building steel or metallic water pipe.

Also he states:
"More common today is grounding to national and local electrical codes. This will involve one or more driven ground rods connected (bonded) to the neutral wire of the electrical service entrance. The purpose of this bond is what is known as life safety ground. It is used for many other things but the code required life safety ground is why it is there to begin with."
The installation of ground rods is absolutely NOT for life safety. This issue has been debated many times and the exprets agree.
Mike Holt has several articles on this subject.

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CE1

Note at the bottom of the page that this document was written in 1995 and it was a military discovery. The military just has a different point of view as to what they need a ground for.