Completed panel change out recently and the inspector left a note requiring that I show the ufer's resistance at 25 OHMS. What is he looking for? How would one test this resistance? Aparently he wants grounds rods if this can not be done. I've never had such a request in five years, some these guys these days seem to be doing what ever they can to justify their jobs. Existing ufers were always excepted before.
Ufer needs 25 OHMS?
- Thread starter Aledrell
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Twoskinsoneman
Senior Member
- Location
- West Virginia, USA NEC: 2020
- Occupation
- Facility Senior Electrician
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Never heard of it for a Ufer
Never heard of it for a Ufer
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I doubt he inspected the ufer before concrete was poured. The house is 25 plus years old the panel was changed using existing ufer. I'm sure an inspector back in the day inspected the ufer, otherwise panel would have never been energized.
It will be much easier and cheaper to drive the two rods and be done with it.
To prove a ufer will really require a 3-point fall of potential test which requires a field of 6 times the length of the foundation.
Or if he will accpet a ground loop tester reading, then all you have to do is rent or borrow one, otherwise they cost over $1000. All you do with them is clamp the grounded circuit conductor and use the utility ground as a reference.
:grin: Well I am old, but to be honest I do not know if a CCE was accepted that long ago?
radiopet
Senior Member
- Location
- Spotsylvania, VA
I do not believe the 25 OHMS comes into play as far as the NEC is concerned regarding the CEE. It appears the issue is only with the following:
250.56 Resistance of Rod, Pipe, and Plate Electrodes. A
single electrode consisting of a rod, pipe, or plate that does
not have a resistance to ground of 25 ohms or less shall be
augmented by one additional electrode of any of the types
specified by 250.52(A)(4) through (A)(8). Where multiple
rod, pipe, or plate electrodes are installed to meet the requirements
of this section, they shall not be less than 1.8 m
(6 ft) apart.
heck to be honest, you could have 1000 OHMS and drive a second rod and reduce it down to lets say 100 OHMS and basically you are done. Before I would worry about testing the CEE, I would ask him if driving (2) rods would make him happy and be done with it.
250.56 Resistance of Rod, Pipe, and Plate Electrodes. A
single electrode consisting of a rod, pipe, or plate that does
not have a resistance to ground of 25 ohms or less shall be
augmented by one additional electrode of any of the types
specified by 250.52(A)(4) through (A)(8). Where multiple
rod, pipe, or plate electrodes are installed to meet the requirements
of this section, they shall not be less than 1.8 m
(6 ft) apart.
heck to be honest, you could have 1000 OHMS and drive a second rod and reduce it down to lets say 100 OHMS and basically you are done. Before I would worry about testing the CEE, I would ask him if driving (2) rods would make him happy and be done with it.
radiopet
Senior Member
- Location
- Spotsylvania, VA
Dang I am a show typer....lol
bphgravity
Senior Member
- Location
- Florida
It's time we all start deleting the value of 25-ohms from our thoughts and memories, especially inspectors...
brian john
Senior Member
- Location
- Leesburg, VA
Update your profile please WITH YOUR HOME LOCATION.
http://www.aemc.com/techinfo/techworkbooks/ground_resistance_testers/950-WKBK-GROUND-WEB.pdf
If you really need to do this test sub it out.
But as noted drive two and walk away.
Or argue (convince) with the inspector, which is what I would do.
http://www.aemc.com/techinfo/techworkbooks/ground_resistance_testers/950-WKBK-GROUND-WEB.pdf
If you really need to do this test sub it out.
But as noted drive two and walk away.
Or argue (convince) with the inspector, which is what I would do.
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