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  • SunEagle
    Super Moderator
    • Oct 2012
    • 15124

    #61
    Originally posted by Sunking
    Steve how are you running the Coax. Underground or over head?

    If underground use a metallic raceway, and use the raceway as your bonding cable. It is permitted to be done that way as it is a pipe, plate, or rod electrode. It will be better than a #6 bare Copper wire. If overhead use the messenger aluminum wire.
    Make sure the underground Conduit is rigid metal and not EMT or PVC.

    Comment

    • Sunking
      Solar Fanatic
      • Feb 2010
      • 23301

      #62
      Originally posted by SunEagle
      Make sure the underground Conduit is rigid metal and not EMT or PVC.
      OK EMT you got me on because I assume they follow code which does not allow EMT underground. PVC well permitted but not metallic
      MSEE, PE

      Comment

      • SunEagle
        Super Moderator
        • Oct 2012
        • 15124

        #63
        Originally posted by Sunking
        OK EMT you got me on because I assume they follow code which does not allow EMT underground. PVC well permitted but not metallic
        You and I understand that EMT is not for U/G installs but some people don't know the code and just think any type of conduit is ok to use. So just saying metallic raceway can be misunderstood by most.

        Comment

        • Sunking
          Solar Fanatic
          • Feb 2010
          • 23301

          #64
          Originally posted by SunEagle
          You and I understand that EMT is not for U/G installs but some people don't know the code and just think any type of conduit is ok to use. So just saying metallic raceway can be misunderstood by most.
          I know, good catch.
          MSEE, PE

          Comment

          • gvl
            Solar Fanatic
            • Mar 2015
            • 288

            #65
            Originally posted by Sunking
            Permitted but not required from a code POV. From a technical POV gains you nothing unless the Sub-Panel is in a different building.
            Understood, right now I'm more concerned if this is just plain wrong and/or dangerous. I think the risk of something bad happening is minimal.

            Originally posted by Sunking
            Can you access the rebar? Is so there is no better earth ground than a concrete encased electrode or UFER ground. Every ammunition bunker in the USA uses a UFER ground. FWIW a UFER ground and NEC Concrete Encased Electrode are not quite the same thing, same principle.
            Thanks, interesting info. No, at least not without breaking of some concrete at one of the rods.

            Comment

            • sdold
              Moderator
              • Jun 2014
              • 1425

              #66
              Originally posted by Sunking
              Steve how are you running the Coax. Underground or over head?

              If underground use a metallic raceway, and use the raceway as your bonding cable. It is permitted to be done that way as it is a pipe, plate, or rod electrode. It will be better than a #6 bare Copper wire. If overhead use the messenger aluminum or steel cable
              It's an existing installation using PVC conduit. #6 bare stranded is run alongside the coax in the same conduit. We are going to be replacing the transmitters, antennas and coax, and there was talk that the #6 wasn't necessary since "the ground at the tower is an RF ground and the ground at the cabinet is an AC ground, and they don't need to be connected together." That seemed like a bad idea to me and I am pushing for keeping that #6. NFPA 780 says to bond them together anyway.

              These are on the AM broadcast band, the ground rod at the tower is one of those chemical grounds, the ones that you set in a hole with bentonite and fill with something that gets good electrolytical action going, I think.

              Comment

              • sdold
                Moderator
                • Jun 2014
                • 1425

                #67
                Originally posted by SunEagle
                Make sure the underground Conduit is rigid metal and not EMT or PVC.
                I wouldn't use EMT, but what's wrong with PVC?

                Comment

                • Sunking
                  Solar Fanatic
                  • Feb 2010
                  • 23301

                  #68
                  Originally posted by gvl
                  Thanks, interesting info. No, at least not without breaking of some concrete at one of the rods.
                  Do you know how to use a Water Auger?
                  MSEE, PE

                  Comment

                  • Sunking
                    Solar Fanatic
                    • Feb 2010
                    • 23301

                    #69
                    Originally posted by sdold
                    I wouldn't use EMT, but what's wrong with PVC?
                    Polly Vinyl Chloride is plastic not metallic. You can use it, but not as a bonding conductor or electrode. Just don't run the bonding conductor inside PVC, run it in dirt.
                    MSEE, PE

                    Comment

                    • sdold
                      Moderator
                      • Jun 2014
                      • 1425

                      #70
                      Originally posted by Sunking
                      Do you know how to use a Water Auger?
                      A few days ago I went to home depot and bought one of those water jet nozzles for the garden hose, the kind that's sort of a poor-man's pressure washer. I put it on the end of a 1/2" PVC pipe with the appropriate fittings. It bored a 1" hole under my 36" sidewalk in about two minutes, I couldn't believe how well it worked. I could have gone under my whole driveway if I had enough pipe.

                      Comment

                      • Sunking
                        Solar Fanatic
                        • Feb 2010
                        • 23301

                        #71
                        Originally posted by sdold
                        A few days ago I went to home depot and bought one of those water jet nozzles for the garden hose, the kind that's sort of a poor-man's pressure washer. I put it on the end of a 1/2" PVC pipe with the appropriate fittings. It bored a 1" hole under my 36" sidewalk in about two minutes, I couldn't believe how well it worked. I could have gone under my whole driveway if I had enough pipe.
                        That is a Water Auger. Works great so long as you do not encounter rocks or roots.
                        MSEE, PE

                        Comment

                        • gvl
                          Solar Fanatic
                          • Mar 2015
                          • 288

                          #72
                          Originally posted by Sunking
                          Do you know how to use a Water Auger?
                          Probably. Can be tricky to find rebar in the concrete I imagine. Wouldn't I need to tie both sides to the rebar that is electrically connected as in metal to metal?

                          EDIT: or did you mean go under concrete to pull a bonding wire?

                          Comment

                          • sdold
                            Moderator
                            • Jun 2014
                            • 1425

                            #73
                            Originally posted by Sunking
                            Polly Vinyl Chloride is plastic not metallic. You can use it, but not as a bonding conductor or electrode. Just don't run the bonding conductor inside PVC, run it in dirt.
                            It's run in the PVC now, should we take it out and run it in dirt instead? Or do you mean just for new installs?

                            Comment

                            • Sunking
                              Solar Fanatic
                              • Feb 2010
                              • 23301

                              #74
                              Originally posted by gvl
                              EDIT: or did you mean go under concrete to pull a bonding wire?
                              Yes using a water Auger.
                              MSEE, PE

                              Comment

                              • Sunking
                                Solar Fanatic
                                • Feb 2010
                                • 23301

                                #75
                                Originally posted by sdold
                                It's run in the PVC now, should we take it out and run it in dirt instead? Or do you mean just for new installs?
                                You ran the bonding wire in PVC? Is it bare or insulated?

                                If bare get it out and run in dirt. You want bare to shunt off lightning current to earth as much as possible. Not to mention it could get warm enough to damage coax. Doubt it but possible.
                                MSEE, PE

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