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Insulation type for typical grounding conductors?

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    Insulation type for typical grounding conductors?

    Does anyone out there know what kind of insulation is used for a typical green, insulated grounding conductor the kind that forms a buried ground loop, such as #4/0 or #2/0? The specification I am looking at calls for XHHW-2 insulation; but this seems like overkill for a simple, single conductor copper grounding conductor intended soley for bonding metal structures, likely to become energized.
    thanks in advance.
    Isaiah

    #2
    Are you talking about a ground wire that's connected to the ground rods &c?

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      #3
      Originally posted by PaulMmn View Post
      Are you talking about a ground wire that's connected to the ground rods &c?
      yes, the so-called grounding loop, i.e. equipotential grid.

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        #4
        AFAIK, the underground portion is naked copper. No insulation!

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          #5
          Originally posted by PaulMmn View Post
          AFAIK, the underground portion is naked copper. No insulation!
          Yes, but this client wants insulated.

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            #6
            I'm confused with the terminology is this a ground ring electrode outlined in 250.52(A)(4)?
            Rob

            Moderator

            All responses based on the 2017 NEC unless otherwise noted

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              #7
              Originally posted by infinity View Post
              I'm confused with the terminology is this a ground ring electrode outlined in 250.52(A)(4)?
              Basically yes

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                #8
                Show the client or whoever wrote the spec this:

                250.52.A.
                Click image for larger version  Name:	Electrical Ground Ring.jpg Views:	0 Size:	8.3 KB ID:	2544305

                It says "bare."

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                  #9
                  A Ufer ground can't use buried insulated conductor. The conductor needs to be in contact with the earth.
                  Ron

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                    #10
                    You want the buried grounding means insulated from the ground?

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                      #11
                      You are talking about two completely separate concepts.
                      Originally posted by Isaiah View Post
                      . . . the kind that forms a buried ground loop, such as #4/0 or #2/0?
                      Here you are talking about the "grounding electrode system." This uses grounding electrodes, such as ground rods or (from your description) ground rings. This requires metal to be in contact with dirt. Any insulation would make the "in contact with dirt" impossible. That is why others have said this wire must be bare copper.
                      Originally posted by Isaiah View Post
                      . . . a simple, single conductor copper grounding conductor intended soley for bonding metal structures, likely to become energized.
                      Here you are talking about bonding conductors, used to connect metal to metal, and not to dirt. It would be internal to the building, and not buried in the ground. Someone will have to check me on this, but I believe these conductors also do not need any insulation system.
                      Charles E. Beck, P.E., Seattle
                      Comments based on 2017 NEC unless otherwise noted.

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                        #12
                        Is there anything about bonding from the main panel to the gas or water piping, running inside, required to be 'green?'

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                          #13
                          Originally posted by PaulMmn View Post
                          Is there anything about bonding from the main panel to the gas or water piping, running inside, required to be 'green?'
                          Nope, it just cannot be one of the colors designated in Article 200 for grounded conductors.
                          Rob

                          Moderator

                          All responses based on the 2017 NEC unless otherwise noted

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                            #14
                            This is a very rare class of dirt worshiper. This type is extremely hard to reason with.
                            Ethan Brush - East West Electric. NY, WA. MA

                            "You can't generalize"

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                              #15
                              Originally posted by charlie b View Post
                              You are talking about two completely separate concepts. Here you are talking about the "grounding electrode system." This uses grounding electrodes, such as ground rods or (from your description) ground rings. This requires metal to be in contact with dirt. Any insulation would make the "in contact with dirt" impossible. That is why others have said this wire must be bare copper.
                              Here you are talking about bonding conductors, used to connect metal to metal, and not to dirt. It would be internal to the building, and not buried in the ground. Someone will have to check me on this, but I believe these conductors also do not need any insulation system.
                              I should clarify: The insulated #4/0 is not really intended to be an electrode, i.e. Ground Ring in the truest sense per 250.52(A)(4).Its really a very large, intricate bonding jumper used to connect grounding electrodes such as ground rods etc installed plant wide. Its also buried only 18" instead of 30". The 'taps' from the #4/0, are #2/0 and #2 insulated. I was simply inquiring as to what was the typical insulation type, such as XHHW-2, THHN/THWN etc, utilized for these conductors.
                              I do however agree, the system would be more effective overall if the conductors were bare instead of insulated - but that is not what the client wants.

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