Thread: Aren't Grounds to be Permanantly Bonded?

Just did a "Pre-Drywall" and saw a Ground rod (rebar into the Basement Floor) connected to a #6 copper wire to the Electrical Panel with an Acorn Nut. It was anything but permanent (I could lossen it by hand)

I thought such connections were supposed to be "Permanently Bonded" with either the thermite connection or the mondo crimp thing that uses a tool that looks like an overgrown bolt cutter?

Did they remove that requirement, or is the AHJ just getting lax?

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I suspect you are thinking of the requirement to be continuous and how two conductors can be made to be considered "continuous" and not spliced.

This is how the grounding electrode conductor is allowed to be connected to the grounding electrode (what you are referring to): (bold and underlining are mine)
- 250.70 Methods of Grounding and Bonding Conductor Connection to Electrodes.
- - The grounding or bonding conductor shall be connected to the grounding electrode by exothermic welding, listed lugs, listed pressure connectors, listed clamps, or other listed means. Connections depending on solder shall not be used. Ground clamps shall be listed for the materials of the grounding electrode and the grounding electrode conductor and, where used on pipe, rod, or other buried electrodes, shall also be listed for direct soil burial or concrete encasement. Not more than one conductor shall be connected to the grounding electrode by a single clamp or fitting unless the clamp or fitting is listed for multiple conductors. One of the following methods shall be used:
- - - (1) A pipe fitting, pipe plug, or other approved device screwed into a pipe or pipe fitting
- - - (2) A listed bolted clamp of cast bronze or brass, or plain or malleable iron
- - - (3) For indoor telecommunications purposes only, a listed sheet metal strap-type ground clamp having a rigid metal base that seats on the electrode and having a strap of such material and dimensions that it is not likely to stretch during or after installation
- - - (4) An equally substantial approved means

The conductor to the first rod needs to be continuous. Being permanently connected was not a requirement. Jerrys post list the methods for connections to the electrode.

Are you sure that it was a rod and not a Ufer ground?

Common ground rods are 8' long and should have their entire length in contact with earth.

Originally Posted by Bob Sisson

Just did a "Pre-Drywall" and saw a Ground rod (rebar into the Basement Floor) connected to a #6 copper wire to the Electrical Panel with an Acorn Nut. It was anything but permanent (I could lossen it by hand)

Your post states you saw two different items.
First you say it was a ground rod, then you say its a rebar into the basement floor.

If it was a grround rod then it should have 8 feet in direct contact with the earth, if it was a 10 foot rod then that is not an issue.
If it was a rebar that goes into the floor then we have an issue, but if its a rebar that goes into the footer then we are alright.
The termination to it should be tight.
If that #6 terminates to a rebar the connector must be rated for use on rebar. A standard ground rod clamp will not suffice. The clamp shall have rebar stamped on it

This was a long time ago, but...

It was a piece of Rebar going into the concrete foundation, obviously someones interpretation of a Ufer...although I prefer to see a Solid Copper wire coming out..

Not Permanently connected? I thought that WAS a requirement... if you loose your ground all sorts of strange things can happen, especially if the utility gnd/neutral isn't as good as it should be..

Originally Posted by Bob Sisson

This was a long time ago, but...

It was a piece of Rebar going into the concrete foundation, obviously someones interpretation of a Ufer...although I prefer to see a Solid Copper wire coming out..

Not Permanently connected? I thought that WAS a requirement... if you loose your ground all sorts of strange things can happen, especially if the utility gnd/neutral isn't as good as it should be..

Bob, a GEC is not intended to be, and isn't, a substitute for, a neutral. The grounding electrodes are there to dump high voltage spikes, like lightening or a fallen higher voltage line that made contact, to ground directly so the current doesn't have to "hunt" for a way - like through your TV/internet cable or computer, you, etc. The fact is most failed service neutrals act the same whether or not there is a grounding electrode. There are exceptions of course, and some are dangerous - whole 'nother book.

All that said, I've never been able to figure out what's so hard about tightening an acorn or other type connector like it's supposed to be. I can't believe how many I've found loose.

What you are referring to is poor work, not a code mandate. Probably no electrical inspection - - - yet, so that was most likely not observed by an AHJ. Regardless of what is spoken, installers and inspectors like to minimise trips / inspections. Kudos to someone for doing it / trying it because re-bar makes such a good ground. Shameful that the effort fell short of it's potential. It could be the approved grounding electrode, if inspected and so noted. Even if inspected, precious few inspectors will check the quality of terminations / electrical connections. Not enough time for that. Still, when bonded to the approved grounding electrode, it can only help.

Interesting....

I have seen just about everything used as a "ground"
- Driven rod of unknown length
-Main (metal) water service Pipe
-Rebar coming out of Foundation
-#4 solid copper coming out of foundation
-Heavy Braided copper going to Multiple Driven Rods 6' apart

Sometimes there is a #4 solid going to the panel, sometimes it is a Green Stranded wire.

In medium old homes, the wire that was going to the "ground" was always pretty solidly connected, often with a thermite weld.

More often than not NEW homes have a loose wire in a clamp on the rod, or a loose acorn joining the Ufer wire to the wire going to the panel.

I know how it is SUPPOSED to work, but I often see measurable current in the ground because the utility ground/neutral has a higher resistance than it "should"...In these cases loosing the "ground" creates lots of weird problems, and some dangerous situations when "ground" has a potential on it...

So, when I see a #4 coming out of the foundation (apparently an Ufer) and there is an Acorn Nut joining it to another #4 going to the Panel that is OK? To me, it is neither continuous, nor permanent. I prefer crimps. Exothermic welds, Maybe even multiple clamps, but a single (loose) acorn just isn't right to me....

Originally Posted by Bob Sisson

So, when I see a #4 coming out of the foundation (apparently an Ufer) and there is an Acorn Nut joining it to another #4 going to the Panel that is OK? To me, it is neither continuous, nor permanent. I prefer crimps. Exothermic welds, Maybe even multiple clamps, but a single (loose) acorn just isn't right to me....

The rebar is the electrode. The #4 is the GEC.

The connection is not required to be permanent.

If the GEC were spliced it would need to be Cadwelded or irreversible crimps.

The loose clamp is an issue.

Originally Posted by Robert Meier

What if there is no rebar and the #4 GEC were run over and connected to the CEE which is made from 20' of #4 Cu, in your opinion would a non permanent connection still be compliant?

Connections to concrete encased electrodes are never made with a permanent means (at least not in residential construction, but I've never seen a permanent connection to a concrete enclosed electrode in commercial construction either - okay, that is two "never" I said, and one should "never" says "never").

The above said, though, once the connection is encased in concrete ... it is pretty darn permanent.

However, the "connection" to the concrete encased electrode is not "permanent".

Originally Posted by Robert Meier

What if there is no rebar and the #4 GEC were run over and connected to the CEE which is made from 20' of #4 Cu, in your opinion would a non permanent connection still be compliant?

You are splitting hairs. When inside the concrete the #4 is a UFER ground (CEE). The instant it leaves the concrete, even though it is still technically part of the UFER it becomes the GEC and a non removable approved connector would need to be used. On the other hand, re-bar extending up out of the concrete is still part of the UFER as re-bar is not an approved GEC, so a screw clamp or other removable clamp can be used to attach a GEC.

As used in the NEC, a non removable or permanent connector is one that would have to be destroyed to be removed as opposed to one that can have a bolt loosened. A clamp approved for concrete encasement, and there are some, would be considered permanent if encased as "normal" access to the bolts is removed.

If we're getting picky about "permanent", I can remove any connector by cutting the wire at each end of it.

Originally Posted by Bill Kriegh

You are splitting hairs. When inside the concrete the #4 is a UFER ground (CEE). The instant it leaves the concrete, even though it is still technically part of the UFER it becomes the GEC and a non removable approved connector would need to be used. On the other hand, re-bar extending up out of the concrete is still part of the UFER as re-bar is not an approved GEC, so a screw clamp or other removable clamp can be used to attach a GEC.

Bill,

I asked Mike Holt this very question about the rebar sticking up into hollow block cells or between framing at a seminar recently. Mike's answer was that it is *not* part of the concrete encased electrode as it is *not* encased in concrete.

Mike went on to say that if the contractor wanted this to be part of the concrete encased electrode, then the contractor would need to fill the hollow block cell or encase the rebar sticking up inside the framed wall in concrete.

Mike than added that, although the rebar is not listed as a grounding electrode conductor and is therefore "not code legal', if the rebar works in the footing as a concrete encased electrode, then the rebar *must be* comparable in current carrying capacity and usefulness as any other grounding electrode conductor as it is in the footing encased in concrete and that one must use the code as a guide and not pick at the technicalities which do not matter and do not raise a cause for concern - that it is better to pick at the life safety aspects of the code.

That said, though, one could drive a ground rod, run the GEC to it un-broken and un-spliced, then bond from there to the rebar sticking up with a clamp rated for rebar. If this is not done, then the regular GEC would need to be permanently and irreversibly connected to the rebar if the rebar was not encased in concrete.

At the end of our brief question and answer period on this issue, Mike said that one could solve all of the side issues as to whether it was technically correct to use the rebar as a part of the GEC by encasing it in concrete above ground where it is exposed in the hollow block cell of in the frame wall.

The take-away-answer was that even though Mike did not have a problem with using the rebar as part of the GEC ... encase that rebar in concrete and move on to other issues, i.e., eliminate the technical issue discussions on its acceptability or non-acceptability for use by making it conform to the code by being part of the "concrete encased" electrode.

In other words ... encase that sucker in concrete and move on real problems.

Originally Posted by Jerry Peck

Bill,

I asked Mike Holt this very question about the rebar sticking up into hollow block cells or between framing at a seminar recently. Mike's answer was that it is *not* part of the concrete encased electrode as it is *not* encased in concrete.

Mike went on to say that if the contractor wanted this to be part of the concrete encased electrode, then the contractor would need to fill the hollow block cell or encase the rebar sticking up inside the framed wall in concrete.

Mike than added that, although the rebar is not listed as a grounding electrode conductor and is therefore "not code legal', if the rebar works in the footing as a concrete encased electrode, then the rebar *must be* comparable in current carrying capacity and usefulness as any other grounding electrode conductor as it is in the footing encased in concrete and that one must use the code as a guide and not pick at the technicalities which do not matter and do not raise a cause for concern - that it is better to pick at the life safety aspects of the code.

That said, though, one could drive a ground rod, run the GEC to it un-broken and un-spliced, then bond from there to the rebar sticking up with a clamp rated for rebar. If this is not done, then the regular GEC would need to be permanently and irreversibly connected to the rebar if the rebar was not encased in concrete.

At the end of our brief question and answer period on this issue, Mike said that one could solve all of the side issues as to whether it was technically correct to use the rebar as a part of the GEC by encasing it in concrete above ground where it is exposed in the hollow block cell of in the frame wall.

The take-away-answer was that even though Mike did not have a problem with using the rebar as part of the GEC ... encase that rebar in concrete and move on to other issues, i.e., eliminate the technical issue discussions on its acceptability or non-acceptability for use by making it conform to the code by being part of the "concrete encased" electrode.

In other words ... encase that sucker in concrete and move on real problems.

Don't really care what Mike Holt says about it. What I care about is how various AHJs treat the issue. We've been over this before and I believe I've posted or forwarded the position of several states (that there would be what you call published clarification of their official position on the matter) to you indicating they view things like I described - right, wrong, or indifferent. The exposed re-bar definitely ISN'T the CEE but it darn sure is PART of it and accepted as such by the AHJs I deal with.

Of course, the other thing I'd tell you is that if you believe that you can leave a length of copper wire exposed at a construction site for the time between a concrete pour and framing that encloses it and secure-able doors and windows, I'd probably like to talk to you about a few bridges.......

I got a good one for you! A few years ago, I was on an inspection with a member of one of our local Inspection Agencies. We were looking at the work that was done by a licensed electrician (whose references were verified by the project Architect) who claimed to have had experience with commercial systems (keep this in mind!), the work was on unoccupied units, and consisted of new 150amp panels, services, etc. to 46 apartments. The Electrical engineer and Architect specified a ground rod at the base of each of the panels, (which were in a utility room), which the electrician did, without exception. BUT, Instead of cadwelding the connections (as was originally specified), he chose to wrap each of the 46 ground rods with several lavers of black electricians tape. On top of all of this tape(which he applied VERY neatly), he used a screw clamp to secure the ground electrode to the copper ground wires. When asked what he was thinking about when he did this, he replied that he thought it looked "neater" and "more-professional" the way he did it(!) - that and the money he claimed to "save" by not doing the required cadwelding caused him to be tossed. After getting him tossed off-site, we had another Electrician go over the first guy's work. While we were there, He found several loose wires on panel busbars, as well as a couple of improperly-installed equipment feeds (to AC condenser units) that were accidents waiting to happen (undersized wiring). Needless to say, EVERYTHING was then examined with a fine-tooth comb, and resulting deficiencies were fixed (- just another day on the job)!

Originally Posted by Bill Kriegh

Of course, the other thing I'd tell you is that if you believe that you can leave a length of copper wire exposed at a construction site for the time between a concrete pour and framing that encloses it and secure-able doors and windows, I'd probably like to talk to you about a few bridges.......

I do believe that, and in fact it happens all the time.

And I have some high and dry Everglades acreage to trade for those bridges ...

Originally Posted by Robert Meier

Jerry, are you saying that in Mike's opinion it is not permissible to stub the rebar up out of the footing for connection to the GEC or a bonding jumper?

Mike's opinion was that it was not that big of an issue and to keep on walking, however, when gently pressed for his response as to whether it was code compliant or not ... his opinion was to just encase the dang thing and end the discussion there.

Mike's position was that the GEC and the CEE are all there for that POOF! (his word) of time of a lightning strike. Here comes the lightning ... POOF! ... it is gone. Not a really big deal ... but not code compliant either ... so make it code compliant and move on.

The rebar is required to be encased in at least 2" of concrete all the way around, that is no problem in a hollow block cell - just fill the cell with concrete. In a frame wall with 2x6 studs, no problem to nail a couple of boards together and encase the concrete in at least 2" of concrete all the way around, but, in a 2x4 wall, getting that 2" of concrete all around the rebar is going to be a bit of a problem. It would be easier to make the dang thing such that it actually was part of the CEE than to argue about how to address it.

Originally Posted by Robert Meier

Whether or not the rebar stubs out of the concrete is IMO a non-issue. As long as it accessible then the GEC can connect to it. The CMP commented on a proposal for the 2014 NEC that the rebar is permitted to exit the concrete for connection to the GEC.

That comment by the CMP does not indicate their thinking as to whether or not the rebar exiting the concrete is part of the CEE or part of the GEC as they state: "PANEL STATEMENT: The Code does not prohibit the rebar from exiting the concrete and connecting with the copper conductor outside the concrete avoiding the corrosion potential. This concern is better handled at the local level, by local methods."

*IF* that rebar is considered as 'part of the GEC', then the connection to the rebar would need to be permanent and non-reversible as one would effectively be 'splicing the GEC' at the rebar.

*IF* that rebar is considered as 'part of the CEE', then the GEC connection to the rebar may be made with a clamp listed for use on rebar.

The CMP statement did not address that difference, only that the rebar is not prohibited from exiting the concrete.

Originally Posted by Robert Meier

I agree, and would you that the same thing would apply to a short piece of the #4 Cu CEE stubbed up as well, providing at least 20' of the conductor were concrete encased?

Yes, but the part which is missing is that the rebar *is not an approved GEC*, while the #4 copper is.

20 ft of 1/2" rebar in concrete that is stubbed up in a protected manner for connection as the GE meets the intent as I interpret the intent for my jurisdiction.
That is to say, unless the rebar morphed into some other physical property when it exited the crete/block in which the GE system would refuse to acknowledge it and look for other paths.

Likewise, a ten foot made electrode, such as a driven rod, 8 feet in earth, with 2 ft in a protected area from mechanical damage, would serve the intent and I would personally call the entire ten feet a ground rod and pass the installation. Now for the important part; listed, wrench-tite, protected, accessible where required, materials for the environment, etc.

By the way, GEC's can be spliced other than permanent and irreversible as long as they are 'tap conductors' to the main GEC that is not spliced (other than permanent and irreversible).
Let the semantics begin

Originally Posted by bob smit

By the way, GEC's can be spliced other than permanent and irreversible as long as they are 'tap conductors' to the main GEC that is not spliced (other than permanent and irreversible).
Let the semantics begin

Correct ... but ...

... but the concrete encased electrode is typically the first, if not the only, electrode used, in which case the GEC is not allowed to be spliced (other than by permanent and irreversible means).

Originally Posted by Jerry Peck

*IF* that rebar is considered as 'part of the CEE', then the GEC connection to the rebar may be made with a clamp listed for use on rebar.

This is how I would consider the rebar. I disagree somewhat with Mike H that is would need to be encased in concrete to be a CEE. I see it as an extension of the CEE. Again it is a matter of semantics.

Agreed J.P..
Ot oh, someone just mentioned semantics again

Originally Posted by Jerry Peck

*IF* that rebar is considered as 'part of the CEE', then the GEC connection to the rebar may be made with a clamp listed for use on rebar.

Originally Posted by Jim Port

This is how I would consider the rebar. I disagree somewhat with Mike H that is would need to be encased in concrete to be a CEE. I see it as an extension of the CEE. Again it is a matter of semantics.

Jim,

How do you explain this, then? (bold and underlining are mine)
- 250.52 Grounding Electrodes.
- - (A) Electrodes Permitted for Grounding.
- - - (3) Concrete-Encased Electrode. An electrode encased by at least 50 mm (2 in.) 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 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 (½ in.) in diameter, or consisting of at least 6.0 m (20 ft) of bare copper conductor not smaller than 4 AWG. Reinforcing bars shall be permitted to be bonded together by the usual steel tie wires or other effective means. Where multiple concrete-encased electrodes are present at a building or structure, it shall be permissible to bond only one into the grounding electrode system.

Here is a scenario for you based on what you are saying:
- All the footing steel is tied together, there are multiple columns with 4' pad footings with steel both ways on 12" centers and with two vertical dowels for the vertical steel, all also tied together and to the footing steel. After the footing and slab is poured, the columns are continued up to the 3rd floor roof with 2-#5 bars vertically in each column, all tied together and all tied to the vertical dowels which are tied to the footing steel.
- At the 3rd floor the electrical service GEC is tied to the column steel.

I know of no AHJ which would pass that connection point of the GEC to the footing steel. Would you pass it? If not, why not?

How is that different that what you are saying, other than the steel being 'just a little longer' above the footing? Heck, in the above scenario, the steel is all encased on concrete too.

Please explain your position.

I think I understand your example Jerry. I am envisioning the Ufer in direct contact with the soil as required, but also tied to other steel bar that extends up to the third floor where it stubs out into a room as the first available point for connection. If this is the case, I don't see how you could turn this down from a grounding standpoint. How you this be any different than 100' of rebar tied together in a horizontal footing where you could connect to a stub sticking out of the footer in a more typical installation. Now if by some chance you only had 19'-6" of steel in contact with the earth before going vertical in your example you would not have a Ufer and could not use it as your grounding means.

If this would be easier by phone, PM me and we can talk.

Originally Posted by Jim Port

If this is the case, I don't see how you could turn this down from a grounding standpoint. How you this be any different than 100' of rebar tied together in a horizontal footing where you could connect to a stub sticking out of the footer in a more typical installation.

Jim,

Neither would be allowed because of what the code states:

Originally Posted by Jerry Peck

- 250.52 Grounding Electrodes.
- - (A) Electrodes Permitted for Grounding.
- - - (3) Concrete-Encased Electrode. An electrode encased by at least 50 mm (2 in.) 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 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 (½ in.) in diameter, or consisting of at least 6.0 m (20 ft) of bare copper conductor not smaller than 4 AWG. Reinforcing bars shall be permitted to be bonded together by the usual steel tie wires or other effective means. Where multiple concrete-encased electrodes are present at a building or structure, it shall be permissible to bond only one into the grounding electrode system.

By definition of what that section is defining as a concrete-encased electrode, the electrode must be:
- 1) encased in concrete
- 2) located horizontally near the bottom of the footing
- 3) or located vertically within that foundation or footing
- 4) which is in direct contact with the earth

Once the rebar leaves that concrete-encased electrode, the rebar is no longer part of the concrete-encased electrode, that rebar becomes the grounding electrode conductor, or part of it if the rebar does not go all the way to the service equipment and terminate there (which would be a bit difficult to do).

The rebar does not meet any of the requirements of a grounding electrode conductor.

Jim, if we hashed this out over the phone, everyone else would be left in the dark as to what was discussed and lead to the end result.

I have not seen any code posted which supports, in any way, that the rebar can be used as the GEC, nor any code which supports, in any way, that the CEE can extend up out of the concrete and not be in contact with the earth.