Irreversible connections for ufer

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ActionDave

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That's stunning to me. I would think each piece of rebar should be welded together at a minimum.

Then again I am known for over thinking things and pissing people off in the process đŸ˜‡ ...and not just w/ electrical theory.
I have this uncanny ability to piss off both Democrats and Republicans, but I digress, lol.
Why? What would be the advantage of welding?
With everything that goes into grounding and bonding, I would think steel wire ties would be a no go. Someone must have tested it at some point, or at least I would hope so.
Again, why?
 

Jerramundi

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Chicago
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Why? What would be the advantage of welding?
Nothing about a piece of steel tie wire seems lacking to you compared to a solid weld? You must be of the generation that used to tell me to cut the bare copper conductor off the light fixture because it's unnecessary, lol :LOL: With all due respect, I don't understand how you put those two side by side and not see a difference.

Granted, I admit my understanding, especially as a mostly residential electrician, isn't exactly quantitively scientific. I could speculate that the hold is stronger because you wouldn't use steel wire ties for load bearing structural work, but you would use welding for such. I could also speculate that a weld is going to give a greater surface area of contact.

There's also the rhetoric of the NEC, which I would argue clearly places certain types of welding in a stricter category than steel wire ties.
I mean for me, just visually and rhetorically welding looks and sounds like it would create a more solid connection that a piece of a steel tie wire.

Perhaps there is data out there, I honestly don't know. Would be interesting to see if there is, but I'm not diving into that tonight, lol.
 

infinity

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Nothing about a piece of steel tie wire seems lacking to you compared to a solid weld? You must be of the generation that used to tell me to cut the bare copper conductor off the light fixture because it's unnecessary, lol :LOL: With all due respect, I don't understand how you put those two side by side and not see a difference.

Granted, I admit my understanding, especially as a mostly residential electrician, isn't exactly quantitively scientific. I could speculate that the hold is stronger because you wouldn't use steel wire ties for load bearing structural work, but you would use welding for such. I could also speculate that a weld is going to give a greater surface area of contact.

There's also the rhetoric of the NEC, which I would argue clearly places certain types of welding in a stricter category than steel wire ties.
I mean for me, just visually and rhetorically welding looks and sounds like it would create a more solid connection that a piece of a steel tie wire.

Perhaps there is data out there, I honestly don't know. Would be interesting to see if there is, but I'm not diving into that tonight, lol.
If you feel that the rebar tied together isn't good enough you could always skip connecting to the rebar and install your own 20' piece of bare #4 copper as the CEE.
 

Hv&Lv

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-
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With everything that goes into grounding and bonding, I would think steel wire ties would be a no go. Someone must have tested it at some point, or at least I would hope so.

I know the answer here, this is a thinking question...
Why is the steel in the concrete in the first place?
is it for electrical grounding purposes or concrete tension and shear strength?
If it’s purpose is electrical, your argument is valid.
 

ActionDave

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Nothing about a piece of steel tie wire seems lacking to you compared to a solid weld? You must be of the generation that used to tell me to cut the bare copper conductor off the light fixture because it's unnecessary, lol :LOL: With all due respect, I don't understand how you put those two side by side and not see a difference.

Granted, I admit my understanding, especially as a mostly residential electrician, isn't exactly quantitively scientific. I could speculate that the hold is stronger because you wouldn't use steel wire ties for load bearing structural work, but you would use welding for such. I could also speculate that a weld is going to give a greater surface area of contact.

There's also the rhetoric of the NEC, which I would argue clearly places certain types of welding in a stricter category than steel wire ties.
I mean for me, just visually and rhetorically welding looks and sounds like it would create a more solid connection that a piece of a steel tie wire.

Perhaps there is data out there, I honestly don't know. Would be interesting to see if there is, but I'm not diving into that tonight, lol.
I know of no rhetoric in the NEC clearly placing certain types of welding in a stricter category than steel wire ties. I do know in 250.52 a continuous length of steel is considered equal to multiple pieces connected together by the usual steel tie wires. I also know you can place 20' of #4 copper wire in the foundation footing, not connect it to the rebar at all, and in the eyes of the NEC you are at an equivalent level of compliance and therefore safety as attaching a #4 copper wire to a 20' continuous piece of rebar or multiple pieces connected together by the usual steel tie wires.

I didn't ask how a welded joint is different than a piece of tie wire, I asked what is the advantage of one over the other in the context of grounding electrodes.
 

Jerramundi

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Chicago
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Licensed Residential Electrician
If you feel that the rebar tied together isn't good enough you could always skip connecting to the rebar and install your own 20' piece of bare #4 copper as the CEE.
Very true. There are other options. And on that note, that one could just "move on" and employ a different methodology... I just want to clarify that my criticisms of the steel wire tie methodology is not a personal attack on anyone who feels that methodology is sufficient. I try to remain mindful of the fact that many of you are more experienced than I am, but simultaneously try to not to be so meek as to not contribute at all to the ideas of civil discourse and debate.

It's tough, because like everyone, I get personally invested in certain methodologies.. simply put, they become part of my ego or the sense of who I am, more specifically, who I am as an electrician.. and when those methodologies are challenged, it feels like a personal attack. This happens to all of us. The key is to recognize that these methodologies are NOT who we are, but just ideas that our egos have latched onto.

I'm not trying to crucify proponents of the steel wire tie methodology, but merely explore, discuss, and debate it.
 

Jerramundi

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Chicago
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I know the answer here, this is a thinking question...
Why is the steel in the concrete in the first place?
is it for electrical grounding purposes or concrete tension and shear strength?
If it’s purpose is electrical, your argument is valid.
The primary purpose of the rebar is for concrete shear strength as far as I'm aware.. it serving as a grounding electrode would be a secondary purpose. But I don't see how this would serve to support or negate the effectiveness of steel wire ties as a grounding electrode connection method...
 

Jerramundi

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Location
Chicago
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Licensed Residential Electrician
I know the answer here, this is a thinking question...
Why is the steel in the concrete in the first place?
is it for electrical grounding purposes or concrete tension and shear strength?
If it’s purpose is electrical, your argument is valid.
I'm not a masonry guy or a structural engineer, so as far as steel wire ties being installed for the purpose of concrete shear strength, I can't really comment... but the intensity and depth of NEC grounding and bonding requirements forces me to question them as a means of a grounding electrode connection method... especially if the means of extending/splicing the GEC are so limited, it would stand to reason that an extension of the GE itself would also be extremely limited and specific... and steel wire ties, to me, just seem like a slapdash solution.

For the portion that serves as the electrode, I would argue steel wire ties are not sufficient, but again, that conclusion is not quantitatively and scientifically based. I'd have to research if anyone has tested them as a means of overall continuity of the electrode. As far as concrete shear strength goes, I have no ground to stand on as to whether they are sufficient or not.
 

Carultch

Senior Member
Location
Massachusetts
The primary purpose of the rebar is for concrete shear strength as far as I'm aware.. it serving as a grounding electrode would be a secondary purpose. But I don't see how this would serve to support or negate the effectiveness of steel wire ties as a grounding electrode connection method...

Structurally, the purpose of rebar in concrete is tensile strength. Raw concrete is strong in compression, but weak in tension. By a ratio of 10 to 1. So typical 4000 psi concrete per its compression test rating can only support 4 psi of tension. Shear strength is a little stronger than its tensile strength, but in typical applications of concrete, shear strength isn't as much of a concern. Shear strength matters in a short length member loaded laterally, like a bolt. Or in other methods of joining components, like welds. However, normal stress matters more in a long member loaded laterally like beams, or loaded axially like columns. Bending stress manifests in both tension and compression, on opposite sides of the neutral axis. A beam with a downward load, is in tension in the bottom, and compression in the top. This is why it is common to strategically locate more rebar on the bottom of downward loaded elements, or any other location where the loads applied will apply tension to the member.

You could assemble the rebar in the form under its own weight alone, and in theory, it would still reinforce the concrete in the direction that matters. The one exception is where two parallel lengths of rebar are joined, where they need to be joined to establish continuity for its tensile strength. The mechanical reason you tie the rebar together, is so it remains assembled as concrete is added to the form. Rebar that is just sitting on the layer below, is at risk of being displaced during the pour.
 

Jerramundi

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I'm not denying that your argument DOES HAVE merit. Your argument IS supported by the NEC.
I'm just being a blasphemer and questioning the NEC, lol.
I know of no rhetoric in the NEC clearly placing certain types of welding in a stricter category than steel wire ties.
In the broader context of the grounding electrode system as a whole, that is the GE and the GEC, the NEC specifies very specific and limited methodologies when extending/splicing the GEC. It would stand to reason that the same logic should apply to extending/splicing/bonding various pieces of rebar together to form a single GE, IMO.

When extending/splicing the GEC, the NEC specifies a very specific type of weld (i.e. exothermic) and does not allow for steel wire ties. This places a certain type of weld in a stricter category than steel wire ties for essentially the same purpose.

Do the GE and GEC not essentially serve the same function?
 

Carultch

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Location
Massachusetts
Do the GE and GEC not essentially serve the same function?

They are two links of the same chain, but there is an essential difference. The GE is what is in electrical contact with the Earth. The GEC is the wire you use to connect the above-ground part of the GE, to the electrical system that requires it.
 

sameguy

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New York
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Master Elec./JW retired
AMP corporation made an impact grounding wedge, what happened to it after being bought out?
 

Jerramundi

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Chicago
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Licensed Residential Electrician
They are two links of the same chain, but there is an essential difference. The GE is what is in electrical contact with the Earth. The GEC is the wire you use to connect the above-ground part of the GE, to the electrical system that requires it.
Yes, I am aware of those differences.

But I am talking about the system as a whole from the end point of the Grounding Electrode buried in Earth/Concrete to where the Grounding Electrode Conductor connects to the Neutral Bus. If one portion of that system is required to be connected via a specific and limited methodology, it stands to reason that that should apply to the whole of that system.

At a minimum, I would say the connection methods should be mechanical compression connectors and listed for grounding and bonding purposes. I don't think steel tie wire is listed for such, but I could be wrong.

Steel tie wire just seems like a splapdash solution for grounding and bonding, but again, my comment isn't quantitively or scientifically based.
 

Dennis Alwon

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When we do the ufer we put 20' copper in the footing and attach it to the rebar. I got the best of both world. A few extra buck is worth not having to worry about all this...
 

infinity

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When we do the ufer we put 20' copper in the footing and attach it to the rebar. I got the best of both world. A few extra buck is worth not having to worry about all this...
Your going to spoil your local inspectors then they will want to see that on all jobs even though it's not required. :LOL:
 

Dennis Alwon

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Your going to spoil your local inspectors then they will want to see that on all jobs even though it's not required. :LOL:

Funny you should say that... I got a call from an inspector 2 days ago about a temporary pole. He said he spent 10 minutes in his vehicle trying to see if he was missing something before he turned me down. He thought maybe I was testing him with the sloppy non-compliant install. I laughed and said that wasn't even my job. The builder accidentally had me down as the contractor.. He was relieved he couldn't quite believe we would do a job like that... So I guess we have him somewhat expecting a decent job from us.
 

LarryFine

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Henrico County, VA
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I see the foundation assembly as a whole as the UFER electrode, not specifically the rebar.

And. the NEC can't really tell the foundation guys how to do their work.
 

ActionDave

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I'm not denying that your argument DOES HAVE merit. Your argument IS supported by the NEC.
I'm just being a blasphemer and questioning the NEC,....
You can blaspheme the NEC all you want, you won't hurt my feelings. You can't even get close to ten percent of the disdain and cynicism I feel for it in its current incarnation.

I think most of the requirements for grounding electrodes are based more on historical bias and opinion than they are to do with anything studied or scientific. I also think the mystique that surrounds grounding electrodes and conductors is misplaced. It's the least important thing in making an electrical system safe.
 
With everything that goes into grounding and bonding, I would think steel wire ties would be a no go. Someone must have tested it at some point, or at least I would hope so.
I think most of the requirements for grounding electrodes are based more on historical bias and opinion than they are to do with anything studied or scientific. I also think the mystique that surrounds grounding electrodes and conductors is misplaced. It's the least important thing in making an electrical system safe.
I was going to say something similar. If the resistance and reliability of the grounding electrode was actually super important (like the NEC implies it is with all of it's dumb outdated non fact based requirements) then maybe it would be worth making a "better" UFER. It really doesn't matter. I have seen countless installations with one rod or no rods at all and they have been fine for 70 years. If you are served with an MGN distribution system the MGN will have far lower resistance than you will ever achieve (granted there may be some arguments for a "local" electrode). Seems like a more sensical thing to hand-wring over would be the NEC's lack of scientific based grounding requirements.
 
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