# Listed for direct burial?



## macmikeman (Jan 23, 2007)

I got presented with a new take on a method for running gec conductors I have used many times in the past with no problem. Inspector questioned my use of copper thhn-thwn for a gec conductor used to the rebar in a footing. Sometimes I use bare #4 but this time I used stranded copper thhn/thwn. His concern is that the conductor may not be listed for direct burial or concrete encasement. My take is if it was bare there would be no insulation to concern ourselves with when using it for a gec. As I recall from memory, nec 250.62 says its ok to use stranded, solid, insulated, or bare copper for this conductor. What do you think?


----------



## HARRY304E (Sep 15, 2010)

macmikeman said:


> I got presented with a new take on a method for running gec conductors I have used many times in the past with no problem. Inspector questioned my use of copper thhn-thwn for a gec conductor used to the rebar in a footing. Sometimes I use bare #4 but this time I used stranded copper thhn/thwn. His concern is that the conductor may not be listed for direct burial or concrete encasement. My take is if it was bare there would be no insulation to concern ourselves with when using it for a gec. As I recall from memory, nec 250.62 says its ok to use stranded, solid, insulated, or bare copper for this conductor. What do you think?


*I don't think it is a problem.*


*



 
250.62 Grounding Electrode Conductor Material. 

The 
grounding electrode conductor shall be of copper, aluminum,
or copper-clad aluminum. The material selected shall
be resistant to any corrosive condition existing at the installation
or shall be protected against corrosion. The conductor​shall be solid or stranded, insulated, covered, or bare.
​

Click to expand...

..*


----------



## rexowner (Apr 12, 2008)

I dunno, this could be an off-based comment, but the #4 stranded bare 
I have has 7 strands, and the #4 THHN has 19 strands. Not the
same thing.


----------



## don_resqcapt19 (Jul 18, 2010)

rexowner said:


> I dunno, this could be an off-based comment, but the #4 stranded bare
> I have has 7 strands, and the #4 THHN has 19 strands. Not the
> same thing.


The code does not specify the number of strands that can be used in the GEC.


----------



## Shockdoc (Mar 4, 2010)

The inspector needs to put the pipe down, the crack made him paranoid.


----------



## nitro71 (Sep 17, 2009)

Copper is copper.. It's fine.


----------



## Dennis Alwon (May 9, 2009)

I would read 250.62. IMO, stranded wire is not a good mix as corrosion can get in between the strands esp. the finer strands.



> 250.62 Grounding Electrode Conductor Material.
> The grounding electrode conductor shall be of copper, aluminum, or copper-clad aluminum. The material selected shall be resistant to any corrosive condition existing at the installation or shall be suitably protected against corrosion. The conductor shall be solid or stranded, insulated, covered, or bare.


----------



## nitro71 (Sep 17, 2009)

It's normal here to use stranded for ground rods. Of course I'm not talking about fine conductors like in SO.


----------



## Dennis Alwon (May 9, 2009)

nitro71 said:


> It's normal here to use stranded for ground rods. Of course I'm not talking about fine conductors like in SO.


I think many areas allow it but I think it is questionable depending on soil conditions.


----------



## sbrn33 (Mar 15, 2007)

Dennis, sometimes you say stupid ****. Copper is copper. Actually stranded has more surface area. which is a good thing in a GEC.


----------



## Dennis Alwon (May 9, 2009)

sbrn33 said:


> Dennis, sometimes you say stupid ****. Copper is copper. Actually stranded has more surface area. which is a good thing in a GEC.


Thank you-- was that necessary- I read the code section


----------



## Dennis Alwon (May 9, 2009)

sbrn33 said:


> Copper is copper.


That is true but we are talking about underground where corrosive conditions exists. Have you ever looked at copper strands and seen corrosion between the strands when run underground. We are not talking about surface area-- oh and BTW copper stranded has the same ampacity as copper solid inspite of the surface area.


----------



## Rockyd (Apr 22, 2007)

Let me know how that #2 and bigger, solid wire works out for ya....:blink::no::laughing:


----------



## sbrn33 (Mar 15, 2007)

yea, maybe harsh but antbody in the trade understands that section is talking about 
*aluminum*


----------



## Dennis Alwon (May 9, 2009)

Rockyd said:


> Let me know how that #2 and bigger, solid wire works out for ya....:blink::no::laughing:


Well I never install 2 and larger underground although they do make #2 solid. If I did I would protect the ends. Again this is my opinion- stupid or not-- I have seen inspectors turn stranded down when installed in the ground based on this section.


----------



## Dennis Alwon (May 9, 2009)

sbrn33 said:


> yea, maybe harsh but antbody in the trade understands that section is talking about
> *aluminum*


Any body in the trade knows aluminum cannot be in the ground to a rod. :thumbsup: Aluminum can be used as an gec but not to a ground rod. 250.64(A)


----------



## macmikeman (Jan 23, 2007)

Ah, now that I am back to the office, let me say thanks for the reply's and also be a bit more specific- there will be no place where it is buried in soil, the wire is connected to a clamp on the rebar of a footing, and then goes up thru the footing into a 3/4 " pvc conduit strapped to a cmu wall and then thru floor joists over to where the meter is going. Concrete encased at the connection point. That will be the one short spot where there is no corrosion protection is at the clamp, the wire has thhn/thwn insulation on it, and as far as I can tell that would be superior to a bare copper wire in concrete strictly speaking as far as the subject of corrosion on the wire. I always have to fend this one individual off on something or other, to my thinking when he can find no problems, he invents some. Its a drag to be me some days.... I think I did it right, and he is full of beans on this, I can find no place that requires a listed conductor for a gec, and it is not a chapter three issue.


----------



## cabletie (Feb 12, 2011)

*(3) Concrete-Encased Electrode. ..........................​*​​​​ in direct contact with the earth, consisting of at least
 6.0 m (20 ft) of one or more bare or zinc galvanized or other
 electrically conductive coated steel reinforcing bars or rods
 of not less than 13 mm (1⁄2 in.) in diameter, or consisting of
 at least 6.0 m (20 ft) of bare copper conductor not smaller than
 4 AWG. ........................................​The inspector may like the 20' bare cooper better than the re-bar, or along with the rebar. I have had one that did. He did not consider rusty rebar tied together with tywire a good grounding electrode. Most of the time the building inspector checks it here and probably does not have an opinion. That time it was an electrical inspector.


----------



## macmikeman (Jan 23, 2007)

cabletie said:


> *(3) Concrete-Encased Electrode. ..........................​*​​​​ in direct contact with the earth, consisting of at least
> 6.0 m (20 ft) of one or more bare or zinc galvanized or other
> electrically conductive coated steel reinforcing bars or rods
> of not less than 13 mm (1?2 in.) in diameter, or consisting of
> ...


When inspectors " consider" a method that is clearly allowed in the code book to be one which they will not allow, they are abusing their office. Its an ego trip plain and simple. Unless the AHJ writes a code for it specifically. Then he is following orders. I don't care for backstabbing receptacle outlets, but if I was a city inspector I wouldn't be taking my authority too far and not allow the use of that method. There is no difference here. The code calls for at least 20 foot of rebar and "if present" then that or a single 20 foot of #4 bare copper wire in the footing. Not required to be one or the other.


----------



## Dennis Alwon (May 9, 2009)

> The inspector may like the 20' bare cooper better than the re-bar, or along with the rebar.


It doesn't matter what the inspector wants. It is done to code. Personally I do exactly what you stated but that is my decision not an inspectors.


----------



## Dennis Alwon (May 9, 2009)

Mac I am not sure of the effects of concrete on the stranded wire. The NEC does not prohibit it but leaves it open with whether it needs protection. Heck some inspector may say that solid wire needs protection also. I would like to see what it would be like in years to come.

I really don't see an NEC issue with the install just thought I'd throw that section out. Concrete pours are different throughout the country so some may have different chemicals then others. I never liked the idea of the connection in concrete to the rebar so that is why I always use 20' of bare copper also.


----------



## BBQ (Nov 16, 2010)

sbrn33 said:


> Dennis, sometimes you say stupid ****. Copper is copper. Actually stranded has more surface area. which is a good thing in a GEC.


It was not stupid at all.

Finer stranding deteriorates faster.


----------



## BBQ (Nov 16, 2010)

Rockyd said:


> Let me know how that #2 and bigger, solid wire works out for ya....:blink::no::laughing:


No one is saying run 2 solid but 2 AWG THHN has a much finer stranding than bare 2 AWG.


----------



## BBQ (Nov 16, 2010)

macmikeman said:


> I got presented with a new take on a method for running gec conductors I have used many times in the past with no problem. Inspector questioned my use of copper thhn-thwn for a gec conductor used to the rebar in a footing. Sometimes I use bare #4 but this time I used stranded copper thhn/thwn. His concern is that the conductor may not be listed for direct burial or concrete encasement. My take is if it was bare there would be no insulation to concern ourselves with when using it for a gec. As I recall from memory, nec 250.62 says its ok to use stranded, solid, insulated, or bare copper for this conductor. What do you think?


In my personal opinion the inspector could choose to fail the job using 110.3(B).

I am not saying they should, just that I think they could. If you ask the manufacturer if THHN is made for DB they are going to say no.


----------



## Dennis Alwon (May 9, 2009)

BBQ said:


> In my personal opinion the inspector could choose to fail the job using 110.3(B).
> 
> I am not saying they should, just that I think they could. If you ask the manufacturer if THHN is made for DB they are going to say no.


LOL- On a similar note I read that someone got turned down because they used thhn to the ground rod simply because the insulation did not have a "W" in it- thus not wet location rated. Sometimes people need to think a little harder.


----------



## Rockyd (Apr 22, 2007)

Dennis Alwon said:


> Mac I am not sure of the effects of concrete on the stranded wire. The NEC does not prohibit it but leaves it open with whether it needs protection. Heck some inspector may say that solid wire needs protection also. I would like to see what it would be like in years to come.
> 
> I really don't see an NEC issue with the install just thought I'd throw that section out. Concrete pours are different throughout the country so some may have different chemicals then others. I never liked the idea of the connection in concrete to the rebar so that is why I always use 20' of bare copper also.


*THE UFER GROUND*​The term "Ufer" grounding is named after a consultant working for the US Army during World War II. The technique Mr. Ufer came up with was necessary because the site needing grounding had no underground water table and little rainfall. The desert site was a series of bomb storage vaults in the area of Flagstaff, Arizona. 
The principle of the Ufer ground is simple, it is very effective and inexpensive to install during new construction. The Ufer ground takes advantage of concrete’s properties to good advantage. Concrete absorbs moisture quickly and looses moisture very slowly. The mineral properties of concrete (lime and others) and their inherent pH means concrete has a supply of ions to conduct current. The soil around concrete becomes "doped" by the concrete, as a result, the pH of the soil rises and reduces what would normally be 1000 ohm meter soil conditions (hard to get a good ground). The moisture present, (concrete gives up moisture very slowly), in combination with the "doped" soil, make a good conductor for electrical energy or lightning currents.
Ufer techniques are used in building footers, concrete floors, radio and television towers, tower guy wire anchors, light poles, etc. Copper wire does not function well as a "Ufer" ground due to the pH factor of concrete (+7pH is common). The use of steel reinforcement as a "Ufer" ground works well and concrete does not chip or flake as has been found with copper. The use of copper wire tied to the reinforcement rods outside the concrete shows none of these problems. 
The minimum rebar necessary to avoid concrete problems depends on:

The type of concrete, its content, density, resistivity, pH factor, etc. 
Amount of concrete surface area in contact with the soil. 
Soil resistivity and ground water content. 
Size and length of the reinforcement rod, wire, or plate. 
Size of the lighting strike current. 
The following chart shows the conductivity of lightning current per foot of Rebar (reinforcement rod). Only the outside Rebar can be counted. Rebar in the center of the footer or foundation does not count in this calculation. In a trench footer only the rebar in the sides and bottom of the footer can be counted.
Rebar Diameter In Inches​Surge Amperes Per Foot​.375​3400​.500​4500​.625​5500​.750​6400​1.000​8150​ 
Mr. Ufer did not know what he had found until he experimented with various lengths of wire in concrete. Today’s informed engineer benefits from Mr. Ufer’s discovery and will tie in the bars of steel reinforcement in a building or other foundation to the building electrical ground. When bonded to the electrical ground, building steel, etc., the buildings reinforced floor and foundation become part of the building grounding system. The result is a much improved grounding system with a very low overall resistance to earth reference. 
For more information follow this link –
http://www.mikeholt.com/mojonewsarchive/GB-HTML/HTML/UferGroundPsi~20030930.htm​


----------



## Dennis Alwon (May 9, 2009)

I have no doubt that a CEE is by far one of the best electrodes we use. I have done 3 point tests on ground rods and CEE's and have found that 2 rods gave me about 89 ohms while a CEE gave me 13 ohms. All that has nothing to do with the connection point and how well it fairs in concrete. I suspect it does well but have never seen a long term study on it although there may be one out there.


----------



## macmikeman (Jan 23, 2007)

Methinks we got us a version of the wording "direct burial" that doesn't apply. I have a cee that is encased in the footing in concrete, not direct burial. My wire does not need to be listed for direct burial, it never contacts any soil or gravel. If somebody considers the footing a direct burial, then by that thinking a romex run behind sheetrock is directly buried behind the sheetrock and therefore it is not listed for a direct burial use and the method of running romex inside 2/4 walls is not to code......

Now if somebody thinks that the footing is a wet location,or a damp location I am pretty sure that thwn is listed for that. :whistling2:


----------



## cabletie (Feb 12, 2011)

macmikeman said:


> When inspectors " consider" a method that is clearly allowed in the code book to be one which they will not allow, they are abusing their office. Its an ego trip plain and simple. Unless the AHJ writes a code for it specifically. Then he is following orders. I don't care for backstabbing receptacle outlets, but if I was a city inspector I wouldn't be taking my authority too far and not allow the use of that method. There is no difference here. The code calls for at least 20 foot of rebar and "if present" then that or a single 20 foot of #4 bare copper wire in the footing. Not required to be one or the other.


I totally agree with you. In my case he did not like the fact that #4 was connected to a 10' piece of re-bar. In that corner of the building they were all short rebar. He did not care that they were all connected together with tywire and ran around the building. He wanted it on a 20' piece of rebar or run bare for 20'. In this case it was almost the same by the time I got to a 20' piece. Changing it was nothing compared to what it would cost over the length of the job with a pissed off inspector. He came up with some off the wall pet peeves, but none of them were costly.


----------



## Rockyd (Apr 22, 2007)

Some inspectors, just "stuck on stupid.":jester:


----------

