# Connection to Concrete Encased Electrode



## jar546 (Jun 6, 2013)

Why is this bothering me?I know Chris Kennedy is very opinionated about this but what do you see?

View attachment 1801


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## gfretwell (Jun 6, 2013)

There are 2 issues

How is the clamp listed?

Does the Visqueen extend under the "foundation" portion of the slab?

The normal practice I see is they stop the Visqueen where the edge of the slab meets the deeper foundation ring.


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## pwood (Jun 6, 2013)

yeah the plastic is not a good thing in the footing.


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## jar546 (Jun 6, 2013)

gfretwell said:
			
		

> There are 2 issuesHow is the clamp listed?
> 
> Does the Visqueen extend under the "foundation" portion of the slab?
> 
> The normal practice I see is they stop the Visqueen where the edge of the slab meets the deeper foundation ring.


To answer your first question, I am not sure that this clamp is listed for connection to rebar since it is stamped 1/2-3/4 which is a pipe size and rebar is in numbers such as 4-5-6.  Again, not sure, it may be.

Second part.  The photo is in the footer section right against the form which is out of camera frame so the vapor barrier termination point would be under the CMU when installed.

This is a photo from a house in SE Florida currently under construction.


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## steveray (Jun 6, 2013)

DB on that clamp?


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## jar546 (Jun 6, 2013)

To alleviate thread drift, I started another thread about the vapor barrier issue here:  http://www.thebuildingcodeforum.com/forum/residential-foundation-codes/11479-monolithic-slab-pours-vapor-barriers.html#post106192

Is there a DB on it?  I have no idea.  If it was, it was on the other side and I did not have a mirror or tools to loosen it to check.  Some manufacturers use a stainless top screw to make ID easier for DB but not all.  Bryan Holland has posted a list of clamps that were approved for DB and encasement but I can't find it right now.  It was a long time ago.


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## Dennis (Jun 6, 2013)

I have never used that style on a concrete encased electrode.  The acorn that I use is db and suitable for concrete


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## Dennis (Jun 6, 2013)

I also don't think that would qualify as a concrete encased electrode with the plastic


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## BSSTG (Jun 6, 2013)

Greetings,

I personally don't like those clamps in any circumstance as I've seen the screws so tight when I kicked it they broke.  It does look like an ug clamp though. I personally will not pass them without the tag still attached showing me they are listed. Not sure about connected to rebar but probably not a big deal? I too like the Acorns. Can't go wrong there.

BSSTG


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## steveray (Jun 6, 2013)

Dennis......Is there anything that says how much of the footing has to be in contact with the earth? (for CEE) It is on the outside....just to play devils's advocate....I might have a hard time arguing that in court without more information...


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## jar546 (Jun 6, 2013)

steveray said:
			
		

> Dennis......Is there anything that says how much of the footing has to be in contact with the earth? (for CEE) It is on the outside....just to play devils's advocate....I might have a hard time arguing that in court without more information...


There is nothing that specifies exactly how much has to be in direct contact with the earth.  In this particular case, the backfill will be the direct contact with the earth.

The clamp is still in question and I would never do it this way.  I actually put 20-22' of bare copper in the footer trench and attach it to the rebar at 2 points with listed clamps.  Is it overkill?  yes, but it is what I did.

Apparently the Palm Beach County Florida inspectors had no problems with this installation.


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## north star (Jun 6, 2013)

*> > >*





> "If a CEE is possible, it shall be included."


Please cite the applicable code, ...either in Cali. Code Land,or in the IRC that "requires" the CEE !.......Thanks !

*< < <*


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## fatboy (Jun 6, 2013)

E3608.1.2, it is new to the 2012 in the IRC. Been in the last two cycles of the NEC.

And yes, in contact with the earth is a requirement.


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## rogerpa (Jun 6, 2013)

2009 IRC



> E3608.1 Grounding electrode system. All electrodes specified in Sections E3608.1.1, *E3608.1.2*, E3608.1.3, E3608.1.4 E3608.1.5 and E3608.1.6 that are present at each building or structure served shall be bonded together to form the grounding electrode system. Where none of these electrodes are present, one or more of the electrodes specified in Sections E3608.1.3, E3608.1.4, E3608.1.5 and E3608.1.6 shall be installed and used.





> *E3608.1.2 Concrete-encased electrode*. An electrode encased by at least 2 inches (51 mm)of concrete, located horizontally near the bottom or vertically and within that portion of a concrete foundation or footing that is in *direct contact with the earth*, consisting of at least 20 feet (6096 mm) of one or more bare or zinc-galvanized or other electrically conductive coated steel reinforcing bars or rods of not less than 1/2 inch (12.7 mm) diameter, or consisting of at least 20 feet (6096 mm) of bare copper conductor not smaller than 4 AWG shall be considered as a grounding electrode. Reinforcing bars shall be permitted to be bonded together by the usual steel tiewires or other effectivemeans. Where multiple concrete-encased electrodes are present at a building or structure, only one shall be required to be bonded into the grounding electrode system.


Won't the outside of the footing be in direct contact with the earth?

Also see NFPA 70-08, 250.50(A)(3)


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## jar546 (Jun 6, 2013)

rogerpa said:
			
		

> 2009 IRC Won't the outside of the footing be in direct contact with the earth?
> 
> Also see NFPA 70-08, 250.50(A)(3)


Yes it will.


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## Dennis (Jun 6, 2013)

steveray said:
			
		

> Dennis......Is there anything that says how much of the footing has to be in contact with the earth? (for CEE) It is on the outside....just to play devils's advocate....I might have a hard time arguing that in court without more information...


  Steve in my opinion if 20' is in touch with the earth then I would say it's a concrete encased electrode.


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## Dennis (Jun 6, 2013)

rogerpa said:
			
		

> 2009 IRC Won't the outside of the footing be in direct contact with the earth?
> 
> Also see NFPA 70-08, 250.50(A)(3)


It is the bottom of the footer they are interested in esp since the requirement specifies near the bottom of the footer


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## jar546 (Jun 6, 2013)

So does anyone know if that particular clamp based on what we can see is rated for that application?


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## jar546 (Jun 6, 2013)

Near the bottom OR vertically


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## steveray (Jun 6, 2013)

"It is the bottom of the footer they are interested in esp since the requirement specifies near the bottom of the footer "

That language goes away in 2011 I believe....but they do also start to talk about membranes in the FPN's...which are also no longer...

Jeff....no idea on the clamp...never been a sparky...


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## Dennis (Jun 6, 2013)

jar546 said:
			
		

> So does anyone know if that particular clamp based on what we can see is rated for that application?


  I have never seen a db clamp that was galvinized.  They make db that look like that but they are bronze or brass


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## Dennis (Jun 6, 2013)

steveray said:
			
		

> That language goes away in 2011 I believe....


You are correct - I hadn't noticed that.


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## steveray (Jun 6, 2013)

Dennis said:
			
		

> You are correct - I hadn't noticed that.


   We are going from 2005 to 2011 this fall and we are doing classes to try to prepare...I am really not that smart....  ....(And the guy I call when I have questions is pretty sharp) I am curious to get clarification on a % or something else that says 20 feet of "X" size to be in contact....foundation waterproofing would kill the wall and top of footing, but the exterior edge should always be in contact...


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## mjesse (Jun 6, 2013)

Are some suggesting that the poly vapor barrier negates the "ground contact" of the concrete?

How many ohms _R_ through 2" of concrete vs. 2" of concrete + 6 mil poly?? c'mon

mj


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## steveray (Jun 6, 2013)

2011 NEC suggests it....unfortunately I cannot cut and paste NFPA.....



			
				mjesse said:
			
		

> Are some suggesting that the poly vapor barrier negates the "ground contact" of the concrete?How many ohms _R_ through 2" of concrete vs. 2" of concrete + 6 mil poly?? c'mon
> 
> mj


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## mjesse (Jun 6, 2013)

steveray said:
			
		

> 2011 NEC suggests it....unfortunately I cannot cut and paste NFPA.....


Found it - _2011 National Electric Code 250.52(3) - Note: Concrete installed with insulation, vapor barriers, films or similar items separating the concrete from the earth is not considered to be in “direct contact” with the earth._

I don't buy into it. 2" rigid foam, sure. 6 mil poly, skeptical.

mj


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## Dennis (Jun 6, 2013)

I thought I posted the Information note about the vapor barrier.  I guess I didn't hit submit.



> Informational Note: Concrete installed with insulation, vaporbarriers, films or similar items separating the concrete
> 
> from the earth is not considered to be in “direct contact”
> 
> with the earth.


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## north star (Jun 6, 2013)

*= = =*

It has been discussed on the Mike Holt Forum...

but if they roll up that 20 linear feet of the copper

conductor, to let's say, ...something around the

diameter of 2-3 inches and place it in direct

contact with the earth in a 2-3 inch diameter area

within the footing, ...then by the Letter of the

NEC, that would be compliant ?

What say ye Electrical Officianados ?

20 ft. of copper conductor where ? ....Also,

20 "consecutive ft.",  or 40 six inch long pieces

of copper ?  :devil

*= = =*


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## BSSTG (Jun 6, 2013)

mjesse said:
			
		

> Are some suggesting that the poly vapor barrier negates the "ground contact" of the concrete?How many ohms _R_ through 2" of concrete vs. 2" of concrete + 6 mil poly?? c'mon
> 
> mj


I'm with you.

BSSTG


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## raider1 (Jun 6, 2013)

jar546 said:
			
		

> Why is this bothering me?I know Chris Kennedy is very opinionated about this but what do you see?
> 
> View attachment 1669


There are DB rated clamps that look just like this that are listed for re-bar, ground rods and water pipes. I would suggest getting the listing of the clamp.

Not all acorn clamps are listed for re-bar either.

Chris


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## raider1 (Jun 6, 2013)

mjesse said:
			
		

> Found it - _2011 National Electric Code 250.52(3) - Note: Concrete installed with insulation, vapor barriers, films or similar items separating the concrete from the earth is not considered to be in “direct contact” with the earth._I don't buy into it. 2" rigid foam, sure. 6 mil poly, skeptical.
> 
> mj


Why would you be skeptical that a layer of 6 mil poly would render a footing not in direct contact with the earth?

The purpose of the 6 mil poly is to provide a moisture barrier between the concrete and the earth. It is the moisture within the concrete that helps lower the resistance of the CEE. Also poly would have electrical insulation properties.

The purpose of the grounding electrode is to limit the voltage imposed on the electrical system from lightning induced currents. If there is dielectric separating the concrete from the earth then the voltage in the concrete would have to reach a limit to where it will break down the dielectric material to make a connection to the earth.

Chris


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## Dennis (Jun 6, 2013)

north star said:
			
		

> *= = =*It has been discussed on the Mike Holt Forum...
> 
> but if they roll up that 20 linear feet of the copper
> 
> ...


IMO, the 20' of copper must be linear not a circular install.  Those Mike Holt guys are crazy.    The wording says one continuous 20' or sections tied together with steel wire for the rebar.  The fact that the rebar mentions length that makes me think linear-- although part 2) does not specifically say length that is what I would surmise.  Who in their right mind would install a ball of copper.


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## jar546 (Jun 6, 2013)

So aside from the clamp issue.  Does anyone else believe that the 2-3" of direct contact with the sandy soil and the 12"+ of contact  of the side of the footer with the backfill constitutes direct contact?  The entire footer will be below grade.


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## jar546 (Jun 6, 2013)

Maybe I'll sneak in at night and connect the CEE directly to the POCO pad mounted transformer.


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## gfretwell (Jun 7, 2013)

This is the entire 2011 250.52(A)(3)



> (3) Concrete-Encased Electrode. A concrete-encasedelectrode shall consist of at least 6.0 m (20 ft) of either
> 
> (1) or (2):
> 
> ...


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## raider1 (Jun 7, 2013)

Dennis said:
			
		

> IMO, the 20' of copper must be linear not a circular install.  Those Mike Holt guys are crazy.    The wording says one continuous 20' or sections tied together with steel wire for the rebar.  The fact that the rebar mentions length that makes me think linear-- although part 2) does not specifically say length that is what I would surmise.  Who in their right mind would install a ball of copper.


The 20 liner foot is backed up by personal conversations with members of CMP5. It is the belief of CMP5 that the CEE should consist of 20' of liner length of re-bar or #4 AWG copper.

I know that the code does not specifically say that but that is the feeling of CMP5.

Chris


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## raider1 (Jun 7, 2013)

jar546 said:
			
		

> So aside from the clamp issue.  Does anyone else believe that the 2-3" of direct contact with the sandy soil and the 12"+ of contact  of the side of the footer with the backfill constitutes direct contact?  The entire footer will be below grade.


In discussions with CMP5 one of the elements that makes a CEE such a good electrode is the weight of the building pushing down on the footing and making good contact with the earth. The side of the footing will not have the weight of the bui8lding to help make the connection.

With that said, there is nothing in 250.52(A)(3) that says the entire bottom of the footing must be in contact with the earth. I think that it is best if the entire bottom of the footing is in direct contact with the earth.

Chris


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## steveray (Jun 7, 2013)

Maybe CMP6 can clear this one up.....


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## raider1 (Jun 7, 2013)

steveray said:
			
		

> Maybe CMP6 can clear this one up.....


I think you mean CMP5.

Somebody must submit a code change proposal to address the issue.

A CMP will not usually just start changing code sections without a proposal.

Chris


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## steveray (Jun 7, 2013)

That was kind of a joke Chris! I have no idea when they change CMP #'s.....I wait for people that are way smarter than me to make those changes or clarifications....I have enough to learn in the NEC without learning all of the science of it. For now I would have to allow the poly but I will try to make sure it doesn't happen...


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## Uncle Bob (Jun 7, 2013)

Get over the clamp (they could use tie wire if they wanted to) or how the copper is attached to the rebar as long as there is 20' of horizontal copper encased in 2" of concrete.  The rebar is not part of the concrete-incased electrode; it just used to maintain the 2" encasement requirement (hold up the copper conductor).  If you didn't have horizontal rebar in the footing and used another method of maintaining the 2" requirement, the electrode is still good.  E3608.1.2  And, the poly cannot enter  (cover the sides) of the footing!  Uncle Bob


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## Dennis (Jun 7, 2013)

steveray said:
			
		

> That was kind of a joke Chris! I have no idea when they change CMP #'s.....I wait for people that are way smarter than me to make those changes or clarifications....I have enough to learn in the NEC without learning all of the science of it. For now I would have to allow the poly but I will try to make sure it doesn't happen...


I always thought that making changes was for someone else but somehow I convinced myself to give it a try.  I was surprised at my success rate.  Many were accepted in principle and some were actually accepted.  It really doesn't hurt and some of my proposals were written to see what the intent really was.


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## Dennis (Jun 7, 2013)

Uncle Bob said:
			
		

> Get over the clamp or how the copper is attached to the rebar as long as there is 20' of horizontal copper encased in 2" of concrete.  The rebar is not part of the concrete-incased electrode; it just used to maintain the 2" encasement requirement (hold up the copper conductor).  If you didn't have horizontal rebar in the footing and used another method of maintaining the 2" requirement, the electrode is still good.  E3608.1.2


Most ec's don't put 20' of copper and attach to the rebar.  Only one or the other is required, however I do both- 20' copper in the footer and then I attach it to the rebar.


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