ECN Forum

UFER ground

Posted By: Artifex

UFER ground - 01/31/18 08:42 PM

I am building a 200,00sq ft warehouse in California with a 2000 amp service panel. My electrician failed to get his UFER ground wire tied into the footing rebar before we poured the footings. This is a concrete tilt-up and the pour back at the walls will be another foot with rebar all the way around. The first part of the footing is 1'-6" deep with continuous #4 rebar. There are #4 slab dowels 12" o.c. that are tied to the continuous footing rebar in 3 places. If I added 20' of #4 rebar tied to these and tied #4 AWG to that also and poured these in my closure strip would that work?
Posted By: twh

Re: UFER ground - 01/31/18 09:46 PM

You need to let your electrician take care of this.
Posted By: ghost307

Re: UFER ground - 02/01/18 01:57 PM

No.

Make your electrical contractor do it right.
Posted By: gfretwell

Re: UFER ground - 02/01/18 08:08 PM

Are there any stub ups from the footer steel that are tied "continuous"? (lapped 24" in the case of #4)
If so you can usually tie to that but you need a continuous path to the steel placed "near the bottom or vertically, and within that portion of a concrete foundation or footing that is in direct contact with the earth" (250.52(A)(3) I doubt they will accept a cold joint on top of the footer as being in direct contact with earth.
Florida has made the Ufer one of the check offs on the footer inspection to avoid these problems and it has been that way for a couple decades.
If you can't find a piece of footer steel you may be chipping your way down to one or coming up with another acceptable electrode. YMMV on that one.

If these "slab dowels" are J hooks with the typical 12" lap on the bottom tied to footer steel, you might find an AHJ with a good enough sense of humor to let you cadweld or even acorn a #4 to several of them up top and call it a continuous connection. I believe it would meet the intent.
Posted By: HotLine1

Re: UFER ground - 02/03/18 01:35 AM

Greg:

Up here, we (Electrical Inspectors) cannot require any chipping or ‘demo’ of a footing when a UFER is missing. That is within the UCC, and alternate electrodes must be installed.

The UFER is the inspection responsibility of the Building Inspectors.
Posted By: gfretwell

Re: UFER ground - 02/03/18 06:39 AM

On a service of that size what other made electrode will be acceptable? I am not sure I would be comfortable with 8' rods, no matter how many they drive. If those are hooks tied to the footer steel, I might be OK with several of them bonded to a #4. I think if you get 6 or 8 of them bonded and then pour that second load of concrete I would put that up against anything but a ground ring.
BTW I have heard of them requiring chipping down to footer steel here when the #4 was lost/stolen. That is one reason why most AHJs were OK with the turned up rebar solution with a 20' stick snap tied to the footer steel for 15 feet or so and about 4' of it turned up in the wall but that was usually 1&2 family.

Posted By: HotLine1

Re: UFER ground - 02/03/18 03:22 PM

Greg:

Your solution was 'accepted' a few times, as a remedy for a misfortune, or a 'missed' item on an inspector. I tend to seek solutions within the 'real world' as opposed to 'black on white' IF I can.

I've already seen #4 Cu ran and terminated on plastic water mains, jumpers on H&C at water heaters with Pex/PVC piping throughout the house, and a lot of other dumb solutions.

I have no issue with your solution. Yes, I have a few ground rings, and the occasional ground plate. Those are the solutions when there are no other options.
Posted By: ghost307

Re: UFER ground - 02/04/18 02:09 PM

I have learned the hard way to avoid cutting slack for someone screwing up.
As soon as they find out that there is a way that I will accept something lesser as a result of them doing it the wrong way; the wrong way becomes the right way.

Than I have someone standing in front of me whining that "You accepted a different makeshift method before when this happened...why are you insisting that it be done right this time?????"
Posted By: HotLine1

Re: UFER ground - 02/04/18 04:12 PM

Ghost:

I get your points on 'slack'. As I said there are real world solutions (NEC Compliant) to solve issues. For the OPs issue, he should have the issue addressed by the design professional of record. A triad rod setup, ground plate, ground ring, or chip the footing may be required. A 2k service, and a 200K SF warehouse must have approved plans and specs by the local AHJ office.

Let me ad that I slipped off the sizes of the service and building with my previous comments, not realizing the size of the project. I still believe there are solutions to any issue.
Posted By: sparky

Re: UFER ground - 02/05/18 10:52 AM

From my readings, a UFER is hands down the best earth contact .

Unfortunately, most sparks up my way are contracted after the 'crete is poured.

The state did make a good faith effort to contact most of the 'crete guys , which ended in 'best guess' stub up's where metering and switchgear might end up.

Yet no spark walking into these can prove their viability, so most of us do the whole grounding routine ,and just include the stub in

~S~
Posted By: ghost307

Re: UFER ground - 02/05/18 12:34 PM

Sparky - I agree completely.
I have known of instances where the GC knew that they screwed up and just stuck a short piece of rebar in the slab; claiming that it was properly bonded to the rest of the rebar.
Without demolishing all of the concrete or acquiring X-ray vision there's no way to know unless a qualified EC put their Mark One eyeball on things before the pour.
Posted By: gfretwell

Re: UFER ground - 02/05/18 06:35 PM

That is why Florida added it to the footer inspection. There needs to be a #4 copper coming up or a green painted rebar for the turn up method. There is some question whether a concrete guy is "qualified" to put an acorn on tho.
Most of them seem to figure it out and fortunately it is the only kind of acorn they have so it is usually the one listed for rebar, buried in concrete..
Posted By: sparky

Re: UFER ground - 02/06/18 11:43 AM

I'm still working on that Xray thing here Ghost ,and i should be so lucky as to be privy to such all inclusive inspection process Greg.

When the timing works out, i've made onto the grids before the 'crete is poured, but that is not as often as it should be.

And then there's other considerations. Was it all over some plastic or hard insulation barrier? How much of it all really makes earth contact?

When i'm trying to pass inspection, it there a way to prove it's efficacy , short of one of those expensive Fluke meters?

~S~
Posted By: gfretwell

Re: UFER ground - 02/07/18 04:25 AM

They are saying if visqueen is present on a footer, it only goes up the sides, the bottom of the concrete is directly in the dirt. Typically there is none anyway. On a momoslab, the visqueen stops at the footer portion of the pour.. They only form the perimeter and they leave the forms up for a week or two so the concrete does not dry out before in is mostly cured, then they back fill pretty much right away. I think the Ufer became so important here because it is really the best electrode available and the building officials are really serious about making sure it is available. Rods are really pretty useless unless you can drive to ground water. This got to be a real issue at the trade groups around here about 15 years ago and there was a sort of Ufermania. The feeling was it "shall be made available" instead of just being used if it "is" available.The cost ends up being less than 2 rods and the hardware so the builders were happy. The compression of building departments after the crash of 08-9 left a whole lot of multi discipline inspectors so the structural guy doing the footer inspection also carries an electrical certification. Guys were usually retained based on how many licenses they held. I have been getting away from all of this so I am not sure how it is going now that they are staffing up again. Hopefully they are teaching the structural guys the principles of the Ufer electrode and they are still being as diligent about being sure it is present when sparky comes along.
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