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Thread: Ufer ground

  1. #11
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    Quote Originally Posted by MRKN View Post
    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.
    Bob

  2. #12
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    Quote Originally Posted by infinity View Post
    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.

  3. #13
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    Quote Originally Posted by infinity View Post
    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.
    Bob

  4. #14
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    Quote Originally Posted by MBLES View Post
    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.
    Bob

  5. #15
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    [QUOTE=petersonra;1918105]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.
    Last edited by MBLES; 05-24-18 at 06:45 PM.

  6. #16
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    Quote Originally Posted by petersonra View Post
    only if it is in the footing.
    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

  7. #17
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    Quote Originally Posted by MBLES View Post
    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
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  8. #18
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    Quote Originally Posted by infinity View Post
    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

  9. #19
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    [QUOTE=MBLES;1918111]
    Quote Originally Posted by petersonra View Post
    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.
    Bob

  10. #20
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    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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