Ufer ground

MBLES

Senior Member
Is a ufer ground required if a foundation or footing is to be used installed? We are putting a generator on a foundation. The foundation has rebar. IS the rebar required to be bonded as part of the grounding electrode system ? Please provide the address in NEC if yes and or no.
 

infinity

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Location
New Jersey
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Journeyman Electrician
Is it just a slab or does it have a footing? Rebar in a slab does not qualify as a CEE so it wouldn't need to be used.
 

MBLES

Senior Member
Is it just a slab or does it have a footing? Rebar in a slab does not qualify as a CEE so it wouldn't need to be used.

Its a 15' x 10' slab with a 2' footing around the sides. So yes it has a footing. is this required by NEC to be part of ground?
 
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MRKN

Member
Location
California, USA
Is it just a slab or does it have a footing? Rebar in a slab does not qualify as a CEE so it wouldn't need to be used.
My understanding is that if there's 20 linear ft of rebar somehow connected together then it qualifies as a CEE and per 250.50 it must be bonded to the grounding electrode system. Maybe you can educate me as to why a slab would be different.
 

infinity

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Location
New Jersey
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Journeyman Electrician
The NEC is a little fuzzy on this one, IMO it is not required to be connected because you are not touching the service. If the building already has a CEE then the code is clear it is not required to be connected.
 

MRKN

Member
Location
California, USA
The NEC is a little fuzzy on this one, IMO it is not required to be connected because you are not touching the service. If the building already has a CEE then the code is clear it is not required to be connected.
It is quite unfortunate that it is so unclear, because it gives AHJs the ammunition to require it for all new foundation work.
 

infinity

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Location
New Jersey
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Journeyman Electrician
Some generators require an electrode so that ufer would be great for it.
Would that require you to connect it to the building GES too?

It is quite unfortunate that it is so unclear, because it gives AHJs the ammunition to require it for all new foundation work.
The NEC wording says that all qualifying electrodes present must be used so that makes it a somewhat gray area. Like I said if you already have a CEE then you are not required to connect other CEE's that are added in the future.
 

MBLES

Senior Member
The NEC is a little fuzzy on this one, IMO it is not required to be connected because you are not touching the service. If the building already has a CEE then the code is clear it is not required to be connected.

The service is a meter bank about 50' away. we are installing a slab/foundation for a skid. I know I mentioned generator but I am clear not its all inclusive. The telco, panel, and generator all sit on skid. The new skid will tie into existing ground ring. I am concerned that the slab the guys already poured needed to have ufer and or if its even needed since it has steel.
 

MRKN

Member
Location
California, USA
The service is a meter bank about 50' away. we are installing a slab/foundation for a skid. I know I mentioned generator but I am clear not its all inclusive. The telco, panel, and generator all sit on skid. The new skid will tie into existing ground ring. I am concerned that the slab the guys already poured needed to have ufer and or if its even needed since it has steel.
If it's already poured and the AHJ didn't hold them up from pouring you're good to go under 250.50 "that are present". Welp, guess it's no longer present now.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
My understanding is that if there's 20 linear ft of rebar somehow connected together then it qualifies as a CEE and per 250.50 it must be bonded to the grounding electrode system. Maybe you can educate me as to why a slab would be different.
only if it is in the footing.

250.52 Grounding Electrodes
...
(3) Concrete-Encased Electrode. A concrete-encased electrode
shall consist of at least 6.0 m (20 ft) of either (1) or (2):

(1) One or more bare or zinc galvanized or other electrically
conductive coated steel reinforcing bars or rods of not
less than 13 mm (1∕2 in.) in diameter, installed in one
continuous 6.0 m (20 ft) length, or if in multiple pieces
connected together by the usual steel tie wires, exothermic
welding, welding, or other effective means to create a
6.0 m (20 ft) or greater length; or
(2) Bare copper conductor not smaller than 4 AWG

Metallic 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.

Informational Note: Concrete installed with insulation, vapor
barriers, films or similar items separating the concrete from the
earth is not considered to be in “direct contact” with the earth.
 

MBLES

Senior Member
Would that require you to connect it to the building GES too?



The NEC wording says that all qualifying electrodes present must be used so that makes it a somewhat gray area. Like I said if you already have a CEE then you are not required to connect other CEE's that are added in the future.

I take 250.50 to mean if all the electrodes are present you would bond together. Where does steel or rebar in a foundation required to be grounded. 250.50a3 says encased electrode not encased rebar. I guess this is where it vague.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
The NEC is a little fuzzy on this one, IMO it is not required to be connected because you are not touching the service. If the building already has a CEE then the code is clear it is not required to be connected.
This is what it says.

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.
This is a different structure so the CEE from the other building would not have to be bonded anyway. having said that, the EGC coming from the other structure to the new skid would effectively bond tha new skid and whatever GES it has to the existing structures GES.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I take 250.50 to mean if all the electrodes are present you would bond together. Where does steel or rebar in a foundation required to be grounded. 250.50a3 says encased electrode not encased rebar. I guess this is where it vague.
One or more bare or zinc galvanized or other electrically
conductive coated steel reinforcing bars or rods
The steel that is encased in the concrete would be the rebar mentioned in the code.

250.50 says all the GE at a structure have to be bonded together. however you are dealing with a separate structure here. The new skid CEE is not associated with the existing structure.
 

MBLES

Senior Member
The steel that is encased in the concrete would be the rebar mentioned in the code.

250.50 says all the GE at a structure have to be bonded together. however you are dealing with a separate structure here. The new skid CEE is not associated with the existing structure.[/QUOT

In Your opinion I wouldnt need the ufer ground isnt needed? Im not trying to get away with anything. I am trying to understand the why i would need a ufer in the first place. I know of plenty of places where this was never an issue.
 
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infinity

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Location
New Jersey
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Journeyman Electrician
I kinda agree with the fuzziness. 250.50a3(1) not less than 1/2 rebar and continous in 20' length. continuous means one piece not 2-10' pieces but thats me
Several pieces can be tied together to create the 20' length. I wrote a proposal to clarify how you measure the 20' but it was rejected. If you have 2-10' pieces with a 6" overlap for the ties is it still 20' of rebar?

250.52(A)(3) Concrete-Encased Electrode. A concrete-encased elec-
trode shall consist of at least 6.0 m (20 ft) of either (1) or (2):
(1) One or more bare or zinc galvanized or other electri-
cally conductive coated steel reinforcing bars or rods of
not less than 13 mm ( 1 ⁄ 2 in.) in diameter, installed in
one continuous 6.0 m (20 ft) length, or if in multiple
pieces connected together by the usual steel tie wires
,
exothermic welding, welding, or other effective means
to create a 6.0 m (20 ft) or greater length; or
 

MBLES

Senior Member
Several pieces can be tied together to create the 20' length. I wrote a proposal to clarify how you measure the 20' but it was rejected. If you have 2-10' pieces with a 6" overlap for the ties is it still 20' of rebar?

I see that now. Thanks. My whole complaint is why or where does it say I need a CEE ground at all? The code does say if a foundation is being poured with rebar that it needs to be bonded together like in pool 680 where it tells you that basically everything metal needs to be grounded. I dont see that in 250.50. IMO Thanks for replies I will see what happens at least i have a start
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
The steel that is encased in the concrete would be the rebar mentioned in the code.

250.50 says all the GE at a structure have to be bonded together. however you are dealing with a separate structure here. The new skid CEE is not associated with the existing structure.[/QUOT

In Your opinion I wouldnt need the ufer ground isnt needed? Im not trying to get away with anything. I am trying to understand the why i would need a ufer in the first place. I know of plenty of places where this was never an issue.
Not what I said. IF the footer for the skid qualifies as a GE, you have to use it. It may not. For instance it may use wire mesh instead of rebar as the steel reinforcement. If there is no qualifying CEE, you should just pound in two ground rods and use them as your GES.

What I said is you do not have to bond the GES of the new skid to the GES of the existing structure, although the EGC of the feeder or branch circuit going from the existing structure to the new skid will effectively bond the two GES together.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
An electrode does not have to be a ground rod. It can be 20' rebar, galvanized pipe sized 3/4", 20' of metal water pipe in the ground, etc.

So once the rebar is tied together to a length of 20' or more then it is an electrode
 
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