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    Grounding Sonotubes

    I'm installing 12" Sonotubes with a plastic coating wrapped around the outside. I know that the note on NEC 250.52(3) says "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." If the bottom of the Sonotube is not wrapped and is direct contact is that adequate for grounding even though the sides are?

    #2
    I would consider this a design issue. What does your engineer-of-record say?

    As an inspector, working to the NEC, I would say, "not considered to be in 'direct contact' with the earth"

    Critique on a design spec:
    Consider a 1' x 6' sonotube. (no, I don't know the length is 6' - just an example)
    Side area is 18.8 ft^2
    Bottom area is .78 ft^2
    Total area is 19.6 ft^2
    Only 4% of the area is in contact with earth.
    Yep, that design sucks

    So, give us some context. And it would likely help if we knew if you had a dog in the hunt.
    Without data you’re just another person with an opinion – Edwards Deming

    Comment


      #3
      In addition to what ice worm said, note that even without any plastic, that would not be considered a CEE. Further, there is probably no need for an electrode at a pole base. Considering those two thing, what are y'all trying to accomplish exactly?
      Ethan Brush - East West Electric. NY, WA. MA

      "You can't generalize"

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        #4
        That's what I figured, I wasn't sure though.

        We're providing grounding for lightning protection for an overhead cable tray.

        Thanks for the replies!

        Comment


          #5
          Drive a rod inside/under the tube and connect a wire to it before you fill the tube.
          Master Electrician
          Electrical Contractor
          Richmond, VA

          Comment


            #6
            Originally posted by calicocal View Post
            I'm installing 12" Sonotubes with a plastic coating wrapped around the outside. I know that the note on NEC 250.52(3) says "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." If the bottom of the Sonotube is not wrapped and is direct contact is that adequate for grounding even though the sides are?
            Sorry, ignorant Brit here.
            Sonotube?

            Comment


              #7
              Originally posted by Besoeker3 View Post
              Sorry, ignorant Brit here.
              Sonotube?
              A pre made form for making round pole bases etc.
              Tom
              TBLO

              Comment


                #8
                Originally posted by ptonsparky View Post
                A pre made form for making round pole bases etc.
                Typically of heavy-duty cardboard, in the classic product. Intended as a temporary form, not for a permanent installation all by its lonesome.

                Comment


                  #9
                  Learn lots here.......

                  Comment


                    #10
                    Originally posted by Besoeker3 View Post
                    Sorry, ignorant Brit here.
                    Sonotube?
                    Imagine the core of a roll of toilet paper or paper towels, blown up to humongous size. Typically anywhere from 6" diameter, up to sizes that can form the pillars of a highway overpass! Lengths for home users are typically in the 6-foot range.

                    Just like the TP cores, the Sonotubes are diagonally-wound; you can still see the diagonal line where the inner layer has imprinted on the concrete.

                    Comment


                      #11
                      I don't think such a tube meets the requirements to be a CEE even if it has enough rebar in it.

                      250.52 Grounding Electrodes.
                      (A) Electrodes Permitted for Grounding.
                      (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.
                      The rebar if any would be vertical in such a tube and so does not meet the requirements of a CEE for vertical rebar in a foundation.
                      Bob

                      Comment


                        #12
                        Originally posted by petersonra View Post
                        ... The rebar if any would be vertical in such a tube and so does not meet the requirements of a CEE for vertical rebar in a foundation.
                        ... or within vertical foundations or structural
                        components or members that are in direct contact with
                        the earth.

                        Vertical components should be okay. Just looking at the physics they should work fine.
                        Without data you’re just another person with an opinion – Edwards Deming

                        Comment


                          #13
                          Originally posted by Besoeker3 View Post
                          Learn lots here.......
                          Google is your friend, search for sonotube returns www.sonotube.com where most of their standard options are detailed.

                          Aside, the manufacturer initially made paper cores, etc, for the US textile industry. As that business declined, they diversified.

                          Comment


                            #14
                            Originally posted by PaulMmn View Post
                            Imagine the core of a roll of toilet paper or paper towels, blown up to humongous size. Typically anywhere from 6" diameter, up to sizes that can form the pillars of a highway overpass! Lengths for home users are typically in the 6-foot range.

                            Just like the TP cores, the Sonotubes are diagonally-wound; you can still see the diagonal line where the inner layer has imprinted on the concrete.
                            Oh Man. After reading that I gotta go!!! Where's the latest Northern Tool catalog, the newspaper, sports section-something!
                            One exit and no waiting

                            Comment


                              #15
                              Where's a Sears catalog when you really need one?

                              Corncobs, anyone?

                              Comment

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