Ufer vs ground rod

[Bnymbill]

In new construction, given that an Ufer or concrete-encased electrode is required by the IRC, would there be any reason to also install a ground rod?

 

[infinity]

No, a ground rod is not required.

Welcome to the Forum.

Please update your occupation to the type of contractor.

 

[Bnymbill]

No, a ground rod is not required.

Welcome to the Forum.

Please update your occupation to the type of contractor.

Thanks, just figured out how to do that and add some details!

I am working on a new construction house and they installed the ground rod in front of the egress window (obvious tripping hazard). My first thought was that they shouldn’t need a ground rod because it should be an Ufer ground. My second thought is, now that they had to grind the ground rod off at the slab and drive a new ground rod, there’s no way to bond to the footer. A calamity of errors that somehow passed inspection!

 

[infinity]

I am working on a new construction house and they installed the ground rod in front of the egress window (obvious tripping hazard). My first thought was that they shouldn’t need a ground rod because it should be an Ufer ground. My second thought is, now that they had to grind the ground rod off at the slab and drive a new ground rod, there’s no way to bond to the footer. A calamity of errors that somehow passed inspection!

You can still use a ground rod if there is a CEE but it is not required. If a standard 8' rod is installed it must be installed so that entire 8' is in contact with the earth so if it's sticking up then it is not installed properly. If you have a CEE and a rod not installed 8' into the earth you can just cut the rod and abandon it.

 

[zbang]

now that they had to grind the ground rod off at the slab and drive a new ground rod, there’s no way to bond to the footer.

The nest question is whether there is actually a compliant CEE, there should be a wire coming up out of the concrete (and it should have been inspected), if there isn't a wire, it may not qualify or someone is chipping out concrete to attach one to the rebar.

Metal components shall be encased by at least 50 mm (2 in.) of concrete and shall be located horizontally within that portion of a concrete foundation or footing that is in direct contact with the earth or within vertical foundations or structural components or members that are in direct contact with the earth. If multiple concrete-encased electrodes are present at a building or structure, it shall be permissible to bond only one into the grounding electrode system

Many people do not consider the slab itself to quality, only footings/foundations that extend downward (but I don't have a citation for that).

 

[Bnymbill]

The nest question is whether there is actually a compliant CEE, there should be a wire coming up out of the concrete (and it should have been inspected), if there isn't a wire, it may not qualify or someone is chipping out concrete to attach one to the rebar.


Many people do not consider the slab itself to quality, only footings/foundations that extend downward (but I don't have a citation for that).

I believe you hit the nail on the head, there’s no ground wire coming out of the footer that would indicate a CEE was properly bonded.

When I first saw it, I figured they must’ve run the ground wire from the footer to the rod, then to the panel. Even though a rod is not required, this shouldn’t be an issue as long as they used the same gauge of wire.

So, they could just cut a 2’x2’ square out of the slab and chip into the footer to clamp the ground wire to a small section of rebar? Is there a minimum length the ground wire has to run with the rebar? I’m trying to find it in the code and will keep reading.

 

[zbang]

When I first saw it, I figured they must’ve run the ground wire from the footer to the rod, then to the panel. Even though a rod is not required, this shouldn’t be an issue as long as they used the same gauge of wire.

Yes, it would be a problem. If the CEE is the primary electrode, the lead from there must go directly (unbroken) to the system bond and the rod would be considered a supplemental electrode.

See 250.52(A)(3) and it's friends, but if the footers weren't inspected you don't know whether they're in direct contact with the dirt without digging down to see. If if they're not, the don't qualify.

You can also read a discussion of this at https://eepower.com/technical-artic...de-2023-basics-grounding-and-bonding-part-11/

(I'm sure there are some nuances that I'm leaving out, equally sure that someone will correct me .)

 

[infinity]

So, they could just cut a 2’x2’ square out of the slab and chip into the footer to clamp the ground wire to a small section of rebar? Is there a minimum length the ground wire has to run with the rebar? I’m trying to find it in the code and will keep reading.

Let's start with what size is the rebar?

 

[Bnymbill]

Thanks for the reference to 250.52, once I read it there, it jumped off the page in the IRC.

I at least have the permit drawings to confirm (as best I can) that there’s no vapor barrier under the footers.

So, it appears that even if the CEE is present, it should not have been “jumped” to the panel by clamping it to the ground rod (this would be under slab so I can’t confirm), then clamping a separate ground wire near the top of the ground rod and running it to the panel. The compliant method would’ve been to go straight from the CEE to the panel without breaking the ground wire at any point.

 

[Bnymbill]

Let's start with what size is the rebar?

two #6 rebar (3/4”) throughout the footers, no vapor barrier indicated on drawings

 

[wwhitney]

I'm unclear on some of the specifics of the OP's installation, but suppose it was this:

- Compliant CEE installed, along with an extra (unnecessary but fine) ground rod.
- GEC from service disconnect to ground rod, sized to the greater of what the ground rod and the CEE individually require.
- Bonding jumper from ground rod to CEE.
- Unnecessary ground rod cut down so it no longer qualifies as an electrode, but the GEC and bonding jumper connections to it are intact.

Then the problem is that the compliant CEE is not connected to the service disconnect with a compliant GEC; the two separate wires, joined to a piece of ground rod that is no longer a proper grounding electrode, do not work as a GEC. In this scenario the solutions that would continue to use the CEE (which is required, as it is present) would include:

- run a new unspliced GEC from the service disconnect to the CEE or
- bypass the defunct ground rod with an irreversible connection between the GEC and bonding jumper, making a new longer GEC.
- bypass the defunct ground rod with a reversible connection, turning the original GEC into a bonding jumper, and install a new electrode (e.g. ground rod) elsewhere with a new unspliced GEC from the service disconnect to the new electrode.

This of course assumes that the bonding jumper to the CEE is accessible at one end or the other. If not, concrete will need to be chipped out, either to make another connection to the CEE, or to find the bonding jumper going to the CEE.

Cheers, Wayne

 

[infinity]

two #6 rebar (3/4”) throughout the footers, no vapor barrier indicated on drawings

So then the rebar qualifies as the CEE and if the place was constructed according to the NEC then the CEE must be used as part of the GES (grounding electrode system).

The CEE can be one of two options you are not required to use both:
1) Connection of a GEC or bonding jumper to the rebar
2) Laying 20' or more of #4 or larger bare copper conductor in the footing.

 

[wwhitney]

So, it appears that even if the CEE is present, it should not have been “jumped” to the panel by clamping it to the ground rod (this would be under slab so I can’t confirm), then clamping a separate ground wire near the top of the ground rod and running it to the panel.

No, that's compliant, as long as the GEC from the service disconnect to the ground rod is properly sized. Only one electrode needs an unspliced GEC connected to it; the other electrodes can be interconnected with bonding jumpers. The problem arose when the ground rod was destroyed as an electrode; now you have no unspliced GEC, and the partial rod is not a compliant way to connect bonding jumpers.

Cheers< Wayne

 

[ActionDave]

Yes, it would be a problem. If the CEE is the primary electrode, the lead from there must go directly (unbroken) to the system bond and the rod would be considered a supplemental electrode.

See 250.52(A)(3) and it's friends, but if the footers weren't inspected you don't know whether they're in direct contact with the dirt without digging down to see. If if they're not, the don't qualify.

You can also read a discussion of this at https://eepower.com/technical-artic...de-2023-basics-grounding-and-bonding-part-11/

(I'm sure there are some nuances that I'm leaving out, equally sure that someone will correct me .)

If needed the grounding electrode conductor can be spliced using irreversible crimps.

 

[Jaybone812]

You can still use a ground rod if there is a CEE but it is not required. If a standard 8' rod is installed it must be installed so that entire 8' is in contact with the earth so if it's sticking up then it is not installed properly. If you have a CEE and a rod not installed 8' into the earth you can just cut the rod and abandon it.

Yessir as long as he has a gec making a connection to a CEE if you wanna slam a rod feel free but its unnecessary but if you do and hit a rock 4’ in , cut it and run without worrying about the inspector finding out lol

 

[Bnymbill]

I'm unclear on some of the specifics of the OP's installation, but suppose it was this:

- Compliant CEE installed, along with an extra (unnecessary but fine) ground rod.
- GEC from service disconnect to ground rod, sized to the greater of what the ground rod and the CEE individually require.
- Bonding jumper from ground rod to CEE.
- Unnecessary ground rod cut down so it no longer qualifies as an electrode, but the GEC and bonding jumper connections to it are intact.

Then the problem is that the compliant CEE is not connected to the service disconnect with a compliant GEC; the two separate wires, joined to a piece of ground rod that is no longer a proper grounding electrode, do not work as a GEC. In this scenario the solutions that would continue to use the CEE (which is required, as it is present) would include:

- run a new unspliced GEC from the service disconnect to the CEE or
- bypass the defunct ground rod with an irreversible connection between the GEC and bonding jumper, making a new longer GEC.
- bypass the defunct ground rod with a reversible connection, turning the original GEC into a bonding jumper, and install a new electrode (e.g. ground rod) elsewhere with a new unspliced GEC from the service disconnect to the new electrode.

This of course assumes that the bonding jumper to the CEE is accessible at one end or the other. If not, concrete will need to be chipped out, either to make another connection to the CEE, or to find the bonding jumper going to the CEE.

Cheers, Wayne

Great write up, can’t believe you were able to nail all of that! I believe what they did (again some is buried so I can’t be 100%) was install a new ground rod next to the footer with a GEC to the CEE. Then, running the GEC from the new rod to the panel. The new ground rod is 4” above the slab, plus 4” slab over 4” stone, so it’s really only about 7’ of soil contact. Wish I had pics or had seen this “fix” in person to verify its bonded to the CEE. I guess it’s possible they used a longer ground rod but don’t see how they could drive it in with joists 8’ above.

 

[Jaybone812]

I'm unclear on some of the specifics of the OP's installation, but suppose it was this:

- Compliant CEE installed, along with an extra (unnecessary but fine) ground rod.
- GEC from service disconnect to ground rod, sized to the greater of what the ground rod and the CEE individually require.
- Bonding jumper from ground rod to CEE.
- Unnecessary ground rod cut down so it no longer qualifies as an electrode, but the GEC and bonding jumper connections to it are intact.

Then the problem is that the compliant CEE is not connected to the service disconnect with a compliant GEC; the two separate wires, joined to a piece of ground rod that is no longer a proper grounding electrode, do not work as a GEC. In this scenario the solutions that would continue to use the CEE (which is required, as it is present) would include:

- run a new unspliced GEC from the service disconnect to the CEE or
- bypass the defunct ground rod with an irreversible connection between the GEC and bonding jumper, making a new longer GEC.
- bypass the defunct ground rod with a reversible connection, turning the original GEC into a bonding jumper, and install a new electrode (e.g. ground rod) elsewhere with a new unspliced GEC from the service disconnect to the new electrode.

This of course assumes that the bonding jumper to the CEE is accessible at one end or the other. If not, concrete will need to be chipped out, either to make another connection to the CEE, or to find the bonding jumper going to the CEE.

Cheers, Wayne

Great breakdown !! My thinking was the CEE and rod type electrode would each have a sole connection !

 

[wwhitney]

Great write up, can’t believe you were able to nail all of that! I believe what they did (again some is buried so I can’t be 100%) was install a new ground rod next to the footer with a GEC to the CEE. Then, running the GEC from the new rod to the panel.

In your descriptions, it is worth distinguishing being a bonding jumper and being a GEC. All following must be interconnected with wires of the proper size: every grounding electrode, and the grounded service conductor, in any order or pattern you like. But one of those wires must have no reversible splices and must connect the grounded service conductor to one of the electrodes. That special wire is the GEC (there may be more than one wire that meets the requirements); the others are called bonding jumpers (and may have reversible splices).

The new ground rod is 4” above the slab, plus 4” slab over 4” stone, so it’s really only about 7’ of soil contact.

So it is not actually a compliant grounding electrode. If the CEE connection is accessible, the simplest solution is to run a new unspliced GEC from the service disconnect to the CEE. The non-compliant rods and their connections can stay in place.

Cheers, Wayne

 

[Bnymbill]

In your descriptions, it is worth distinguishing being a bonding jumper and being a GEC. All following must be interconnected with wires of the proper size: every grounding electrode, and the grounded service conductor, in any order or pattern you like. But one of those wires must have no reversible splices and must connect the grounded service conductor to one of the electrodes. That special wire is the GEC (there may be more than one wire that meets the requirements); the others are called bonding jumpers (and may have reversible splices).


So it is not actually a compliant grounding electrode. If the CEE connection is accessible, the simplest solution is to run a new unspliced GEC from the service disconnect to the CEE. The non-compliant rods and their connections can stay in place.

Cheers, Wayne

Thanks for the distinction between GEC and bonding jumpers, will definitely help me understand the code as I continue reading!