The infamous and elusive UFER

[Npstewart]

Good Evening everyone.

(NEC 2017)
For years and years I’ve been getting calls for the occasional “We missed connecting to the UFER, can you write a letter because it’s covered in concrete ?”

I know this happens inadvertently and the fact is once it happened there’s nothing that can be practically done about it.

Again, for years and years the municipality has ALWAYS accepted a letter omitting the requirement for the UFER, have always accepted 2 driven ground rods per 250.52, but for some odd reason, they want the GC to chip up the concrete and find it for connection. Despite me sending a meticulous code path, complete with screen shots, they are still insisting the concrete be chipped up.

Is anyone aware of any existing NFPA interpretations or published code paths that would prevent them from excavating poured concrete?

Any help appreciated - and I mean that.

 

[tom baker]

Ufer has been in NEC for many years, WA AHJ requires exposing rebar to connect if connection not made

 

[Npstewart]

Ufer has been in NEC for many years, WA AHJ requires exposing rebar to connect if connection not made

Out of curiosity, How do they know it’s a suitable grounding electrode unless enough of it was exposed?


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[Carultch]

Out of curiosity, How do they know it’s a suitable grounding electrode unless enough of it was exposed?


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A pre-pour walkthrough, or a review of pre-pour photos.

 

[Npstewart]

A pre-pour walkthrough, or a review of pre-pour photos.

What if that didn’t happen though? What if the slab was poured before inspection and there weren’t photos? That’s generally what happens from
My understanding.


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[curt swartz]

In most if not all jurisdictions around me they will not sign off on the footings unless the UFER is installed. Its all combo inspection so doesn't require a separate electrical inspection.

 

[LarryFine]

Probably because building code requires more than enough rebar to qualify as an electrode.

 

[Npstewart]

In most if not all jurisdictions around me they will not sign off on the footings unless the UFER is installed. Its all combo inspection so doesn't require a separate electrical inspection.

Such a great idea. Just not something they do in my area which obviously causes issues.


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[Npstewart]

Probably because building code requires more than enough rebar to qualify as an electrode.

What if it’s slab on grade with a vapor barrier?


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[infinity]

Out of curiosity, How do they know it’s a suitable grounding electrode unless enough of it was exposed?

Around here it gets inspected by the building inspector prior to the pour. No CEE, no concrete.

 

[hbiss]

...for years and years the municipality has ALWAYS accepted a letter omitting the requirement for the UFER, have always accepted 2 driven ground rods per 250.52, but for some odd reason, they want the GC to chip up the concrete and find it for connection. Despite me sending a meticulous code path, complete with screen shots, they are still insisting the concrete be chipped up.

Probably because you have been given ample time to understand the requirement. If you have to have to chip and break concrete because you didn't do it, you won't forget as easily next time!

-Hal

 

[Npstewart]

Seems like this one has went pretty off topic. Thanks anyway guys.


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[TX+ MASTER#4544]

Good Evening everyone.

(NEC 2017)
For years and years I’ve been getting calls for the occasional “We missed connecting to the UFER, can you write a letter because it’s covered in concrete ?”

I know this happens inadvertently and the fact is once it happened there’s nothing that can be practically done about it.

Again, for years and years the municipality has ALWAYS accepted a letter omitting the requirement for the UFER, have always accepted 2 driven ground rods per 250.52, but for some odd reason, they want the GC to chip up the concrete and find it for connection. Despite me sending a meticulous code path, complete with screen shots, they are still insisting the concrete be chipped up.

Is anyone aware of any existing NFPA interpretations or published code paths that would prevent them from excavating poured concrete?

Any help appreciated - and I mean that.

Hello, Npstewart.

The 2023 NEC and Part III Grounding Electrode System and Grounding Electrode Conductor. Section 250.50 is where you will find your answer about
"missed connecting to the Ufer." Other wise known as the concrete encased electrode [250.52 (A) (3)].

Now back to 250.50 Grounding Electrode System. The second sentence "If (If , that word is new entry in 2023 NEC ) none of these grounding electrodes exist,........one or more as specified in250.52 (A)(4) Thru (A) (8) shall be installed and used".

250.52 (A) (4) Ground Ring. "A ground ring encircling the building......." Go back to 250.50 ".... If none of these........" install one or more of the grounding electrodes specified in 250.52(A) (4) shall be installed and used."

Go back to where we started. Read the Exception. ...."if the rebar is not accessible for use without disturbing the concrete."
If you have a 2023 NEC Handbook, read the commentary following the section 250.50.

"The NEC "does not specify that concrete encased type electrodes have to be installed, only that where they have been installed......"
You don't have to chip out the concrete to get access to the rebar. You may need to install a ground ring or other grounding electrode to satisfy the AHJ or other city official.

My final word in this Code requirement is that you must educate the builder or owner as well as keeping yourself ahead of the concrete contractor.

You may use1/2 inch rebar that's least 20 foot long or several pieces tied together and place it as required by NEC in the footing per 250.52(3) and turn it up above finished pour where your service will be. So you have some options.

Good advice.....stay in touch with the builder and keep your licensed electricians informed so they will know and watch the jobs as they progress.

Thanks for reading.
TX+MASTER#4544

 

[Npstewart]

Hello, Npstewart.

The 2023 NEC and Part III Grounding Electrode System and Grounding Electrode Conductor. Section 250.50 is where you will find your answer about
"missed connecting to the Ufer." Other wise known as the concrete encased electrode [250.52 (A) (3)].

Now back to 250.50 Grounding Electrode System. The second sentence "If (If , that word is new entry in 2023 NEC ) none of these grounding electrodes exist,........one or more as specified in250.52 (A)(4) Thru (A) (8) shall be installed and used".

250.52 (A) (4) Ground Ring. "A ground ring encircling the building......." Go back to 250.50 ".... If none of these........" install one or more of the grounding electrodes specified in 250.52(A) (4) shall be installed and used."

Go back to where we started. Read the Exception. ...."if the rebar is not accessible for use without disturbing the concrete."
If you have a 2023 NEC Handbook, read the commentary following the section 250.50.

"The NEC "does not specify that concrete encased type electrodes have to be installed, only that where they have been installed......"
You don't have to chip out the concrete to get access to the rebar. You may need to install a ground ring or other grounding electrode to satisfy the AHJ or other city official.

My final word in this Code requirement is that you must educate the builder or owner as well as keeping yourself ahead of the concrete contractor.

You may use1/2 inch rebar that's least 20 foot long or several pieces tied together and place it as required by NEC in the footing per 250.52(3) and turn it up above finished pour where your service will be. So you have some options.

Good advice.....stay in touch with the builder and keep your licensed electricians informed so they will know and watch the jobs as they progress.

Thanks for reading.
TX+MASTER#4544

Thanks. This is what I was looking for and your code path is what I concluded as well. Also, I appreciate you mentioning the 2023 NEC.

When I read this section it doesn’t really indicate that you have to create the grounding system and then connect to it. It’s essentially saying if it’s there, then you need to connect to it but it quite literally says not to go excavating the concrete to get to it.


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[tom baker]

Probably because building code requires more than enough rebar to qualify as an electrode.

Correct

 

[Npstewart]

Correct

But what if the rebar is encased in a slab on top of a 10 mil vapor barrier?


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[zbang]

But what if the rebar is encased in a slab on top of a 10 mil vapor barrier?

Then it doesn't qualify as a CEE ("in direct contact with earth"). 250.52(A)(3), The informational note confirms this.

 

[roger]

Thanks. This is what I was looking for and your code path is what I concluded as well. Also, I appreciate you mentioning the 2023 NEC.

What Tex didn't include is that the exception only applies to existing buildings or structures. In a new building it would be mandatory to use it.
NC amended their state code to read "if available" but FL has not.

 

[infinity]

What Tex didn't include is that the exception only applies to existing buildings or structures. In a new building it would be mandatory to use it.

That's correct. So on a new build if you forget to install one out comes the chopping gun.

 

[Npstewart]

That's correct. So on a new build if you forget to install one out comes the chopping gun.

Unless it’s slab on grade with a vapor barrier, in which case it does not qualify anyway. Correct ? So, no chopping gun?


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