Ufer ground for detached garage service panel

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  #1  
Old 02-27-07, 11:07 PM
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Ufer ground for detached garage service panel

Hi all -
I am in Denver Colorado, and I am building a detached garage.
To power the garage, I have installed a sub panel, fed from my home's service panel. I asked the inspector what he wanted to see in this installation, and he told me what he wanted - with one major exception: he mentioned nothing about a Ufer ground.

I poured my pad in Dec - monolithic slab. The garage was framed, and I ran 3 6 gauge THHN (-2) wires through underground conduit to the garage, OCPD is a 50 amp breaker on the service panel, which is on the house. I drove a grounding rod at the garage, which is bonded at the sub panel with #4 solid copper. I called in my rough, and I flunked because he says I need a Ufer ground (he called it Uffer, but I figure that is what he is referring to).

10 weeks ago, I asked this guy specifically what he wanted to see to establish that sub panel, and he never mentioned this requirement. The guy who did my flatwork has been building garages in Denver for 20 years, and says he never heard of this. Denver building department tells me that I should have known, as they sent out a letter in 2003 to this end (to whom, I do not know). I searched their mods to the NEC, and I find no mention of this. I could not get ahold of my inspector to discuss this with him, but another city inspector told me that this is now required, and that the only remedy is a limited demo on the slab to expose a piece of rebar which I need to clamp to. He said pouring a separate foundation, which I will need anyway for a required retaining wall and placing the CEE/Ufer in that would not be acceptable. I really don't want to do this, as I fear what it may do to the integrity of my foundation - I know where the rebar was before the pour, but I don't wish to engage in a destructive hunt for it.

Any other workarounds which I could suggest to my inspector when I get ahold of him?

1 - I don't know how I was supposed to know about this. Every electrician and contractor to whom I have spoken think it is BS and not necessary. If this is not published for me to see, how can they expect me to do this before inspection? I have heard that some municipalities which require Ufers will not pass a foundation inspection without the clamp in place, but Denver, evidently, does not.
2 - I had a specific conversation with the inspector regarding the new panel, and this was never mentioned. Of course, I took him at his word, and had no reason to ask for this in writing. Truth be told, I had no idea what a Ufer ground was at the time.

Do I have any recourse, or does anyone know of an acceptable workaround? Can I, for instance, suggest a second ground rod? Running another ground wire back to the house and bonding to a second ground there? Argue that they should let me put a Ufer in my retaining wall foundation?

Any advice is appreciated.
 
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  #2  
Old 02-28-07, 05:19 AM
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Herbert Ufer had a great idea during WWII to protect bomb storage buildings from static electricity, and it worked. I have seen this installed in milking operations for cows to cut down on the static electricity. Without it the cows will just hop around once you connect them to the milkers.
BUT, for a residence, I think it is overkill, as a standard grounding rod should suffice. You are caught in Catch 22, since you can't prove a conversation took place, and he will certainly deny it.
And worse news....they rule. You may ask for specific referrals in their code requirement that stipulate this is mandatory, or even ask for a review in the absence of such documentation. Good luck with a municipality.
 
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Old 02-28-07, 07:42 AM
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Did you submit written plans when you got your permit? Were these plans approved? I know that approval of plans does not constitute prior approval of the construction, but it might help your case.
 
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Old 02-28-07, 08:01 AM
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Inspectors are not allowed to make up code as they go. Ask him for a code reference. That have to quote a code reference for a violation to be present. If he can site the local code then I don't see how you can get around this unless there is some way to apply for an exception.
 
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Old 02-28-07, 05:50 PM
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Thumbs up Update - resolved

I talked to the inspector this morning, and he believes he made a mistake - I don't need a Ufer on the garage unless I were to feed the house from service on the garage. I don't know if I am more relieved or pissed off that he did not bother to note the location of my service panel at the inspection before he failed me.

C'est la vie.

Thanks to all for your advice.
 
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Old 02-28-07, 07:40 PM
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Glad you were able to get it resolved and still be friends with the inspector. You will need him again. Just don't milk cows in the garage!
 
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