The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Calling all Non-US members!! (Non-US only)
by aussie240
Yesterday at 02:39 AM
Photo Upload Tutorial
by DanK
12/06/16 11:35 PM
Sprinklered equipment 26-008
by bigpapa
12/02/16 04:24 PM
On Delay Relay with Auto Reset
by Potseal
12/01/16 09:59 AM
Wow, that was close!
by jraef
11/28/16 07:06 PM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 13
HotLine1 9
Texas_Ranger 8
sparkyinak 7
Trumpy 6
Who's Online
0 registered (), 196 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Page 1 of 3 1 2 3 >
Topic Options
Rate This Topic
#168736 - 09/13/07 12:06 PM Re-Bar as part of the Grounding Electrode System
George Little Offline
Member

Registered: 01/18/04
Posts: 1492
Loc: Michigan USA
Based on the '05 NEC the wording in 250.50 states that "if present" all of the listed electrodes will be included in the GES. In some areas the re-bar os the foundation and or basement walls consist of numerous pieces of re-bar that are not tied together. If the bars are not 20 feet and => 1/2 in in diametr then they don't qualify as an electrode and would not be included in the GES. It's only the larger projects where engineering spec out the re-bar and the tying together that we are fased with using the re-bar as an electrode. Since the State of Michigan is just now adopting the '05 NEC I wonder what the rest of the areas are doing? Is there any wording in the building codes that would have the builders tying the re-bar together to form an electrode?
_________________________
George Little

Top
2014 / 2011 NEC & Related Books and Study Guides
#168737 - 09/13/07 01:06 PM Re: Re-Bar as part of the Grounding Electrode System [Re: George Little]
renosteinke Offline
Cat Servant
Member

Registered: 01/22/05
Posts: 5305
Loc: Blue Collar Country
I'm a bit confused; I don't think I have ever seen rebar or even mesh that was not tied together. A simple piece of tie wire holding the pieces in alignment counts ... there's no need for anything fancier.

I have seen isolated bits used when a repair or change was made to an existing pour .... and I've never seen those connected to the existing bar.

I don't think you HAVE to tie the rebar to the GEC, unless that rebar is accessible. For a Ufer, a length of copper wire will suffice - and it need not be in contact with th rebar. The rebar spec only applies, as I understand it, if you wish the rebare alone to be the "Ufer," without any copper wire.

Maybe I'm just confused ...

Top
#168741 - 09/13/07 05:10 PM Re: Re-Bar as part of the Grounding Electrode System [Re: renosteinke]
wire_twister Offline
Member

Registered: 07/25/07
Posts: 265
Loc: Georgia USA
In my part of the world as of jan. 2007 all new construction must have a piece of the rebar brought above grade, it must be tied to the bar in the footing/slab,and must be bonded to the GEC or the electrode itself with no smaller than a 6 awg solid copper wire by approved clamp or CAD weld. I have to do one tomorrow for a garage addition on the opposite end of house from service, 85 feet away. Homeowner will not be happy!!
_________________________
Jimmy

Life is tough, Life is tougher when you are stupid

Top
#168742 - 09/13/07 05:17 PM Re: Re-Bar as part of the Grounding Electrode System [Re: renosteinke]
George Little Offline
Member

Registered: 01/18/04
Posts: 1492
Loc: Michigan USA
Reno- The '02 NEC said "if available" and the feeling was that if it was not exposed it was not available. The '05 NEC says "if present" so this makes it mandatory to include it as an electrode and include it with any other electrodes that are present as the Ground Electrode system. My question had to do with the fact that if they weren't loug enough did we need to tie them together?

250.50 and 252.52(C)


Edited by George Little (09/13/07 05:18 PM)
_________________________
George Little

Top
#168744 - 09/13/07 05:59 PM Re: Re-Bar as part of the Grounding Electrode System [Re: George Little]
HotLine1 Offline

Member

Registered: 04/03/02
Posts: 6804
Loc: Brick, NJ USA
George:
Here in NJ:
Ufer ground is installed on the majority of new construction, resi & comm. 20' of rebar; 1 piece or tied, with #4 cu connected to it by an approved clamp or exothermic welding (Cadweld) It is inspected by the building inspector when footing is inspected. (Per NJ UCC)

Now...who installs the #4 & clamp...probably the mason.

If & when it's on the opposite side of building from service location..the EC extends it to the main disco or main panel; again with Cadweld or a crimp barrel.

I get to 'see' it on service inspection.

As to the actual rebar emerging from the concrete....thats a "NO-NO" opinion from the State DCA. Opinion is basically that the rebar will rust as it is exposed; as opposed to being encased in concrete.

Ufer ground and water pipe (when it's copper)and the grounding is done.

BTW, more and more resi is going with plastic piping throughout.

Stay safe
_________________________
John

Top
#168749 - 09/13/07 07:07 PM Re: Re-Bar as part of the Grounding Electrode System [Re: HotLine1]
leland Offline
Member

Registered: 08/20/07
Posts: 856
Loc: Lowell area, Ma. USA
So Wich one is supplemental? Ground rods or rebar?

My situation. My plan.

PSNH (utility) Requires the GEC to go to the meter can.

So I'm gonna' put 2 rods in and bond at the meter.
Then the rebar is going to go to the panel (inside right above the panel now)
All Plastic water. (PEX and well)

I see no problems, Do any of you?

Top
#168754 - 09/13/07 08:47 PM Re: Re-Bar as part of the Grounding Electrode System [Re: leland]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9045
Loc: Estero,Fl,usa
The Ufer has been part of the footer inspection in Florida for years.
This is an old picture (back when they were building houses) of the general practice.

http://members.aol.com/gfretwell/ufer.jpg
_________________________
Greg Fretwell

Top
#168762 - 09/14/07 06:35 AM Re: Re-Bar as part of the Grounding Electrode System [Re: gfretwell]
Jim M Offline
Member

Registered: 08/10/01
Posts: 453
Loc: Chestertown, MD, USA
I was under the impression that if a Ufer ground was used there was no need for any other grounds.

Can anyone confirm this?

Top
#168763 - 09/14/07 06:47 AM Re: Re-Bar as part of the Grounding Electrode System [Re: Jim M]
renosteinke Offline
Cat Servant
Member

Registered: 01/22/05
Posts: 5305
Loc: Blue Collar Country
You are more or less correct, Jim. You certainly do not need a ground rod, plate, etc.

You still need to bond the plumbing, though. The NEC, notorious for poor grammar, continues to refer to the water bond as a grounding electrode. It's pure semantics .... with a Ufer we're not relying on the plumbing as a GEC, but are instead concerned with clearing a fault to the plumbing.

Top
#168774 - 09/14/07 03:09 PM Re: Re-Bar as part of the Grounding Electrode System [Re: renosteinke]
Alan Nadon Offline
Member

Registered: 03/10/05
Posts: 398
Loc: Elkhart, IN. USA
George,
We had this problem until we explained to the building inspectors that they were approving foundations that were not being built to the Building Code.
All the rebar is to be installed on blocks or chairs and tied together before the pour.
Dumping rebar into the foundation during the pour or having it stick out of the concrete into the earth is not the correct way to install the rebar.
On residential we have convinced most of the contractors to use 3/8 rod when they feel they must have rebar.
Those that use 1/2 must install it correctly and either bring it up inside in a dry space or have the copper connected before the pour.
This is definately a topic that needs to be covered at all Chapter and Section meetings of the Inspectors.
Even after I thought I knew it all I found out I didn't know it a lot.
On commercial jobs it is OK to go from the rebar to the building steel and building steel to the service. It does not have to go all the way to the service from the rebar.
The connection to the steel must be accessable.
The Code does not require a ground rod if the Concrete encased electrode is used However, the utility Co. usually will require Grd rods because the cannot see or confirm the Ufer ground.
If it was easy anyone could do it, and you couldn't charge $75 a hour. \:\)
_________________________
Alan--
If it was easy, anyone could do it.

Top
Page 1 of 3 1 2 3 >



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals