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CADWELD & PGE

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    CADWELD & PGE

    I was working on a job in NoCal where we'd be fed 3-ph by PGE.
    They required 2 grounds for the pad-mount transformer.

    Their "Green Book" specified the type of clamp.

    I wanted to CADWELD the wire to the rod. They didn't want to accept that and could not explain why.

    I did "when in Rome" and clamped the wire AND then CADWELDed it too.

    But I still wonder -- why wouldn't they want a welded connection?

    #2
    Depending on the size of the conductor, Cadwelds may have internal voids/pits that can reduce the cross-sectional area of the connection and reduce its effective ampacity. The phenomena can begin around #4 AWG. Truthfully, this isn't generally a serious problem with grounding electrode connections but it can be a big deal with some bonding connections.
    [COLOR=black]"Bob"[/COLOR]
    Robert B. Alexander, P.E.
    Answers based on 2017 NEC unless otherwise noted.

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      #3
      Thanks; I'd never heard of such.

      Comment


        #4
        Originally posted by Open Neutral View Post
        I was working on a job in NoCal where we'd be fed 3-ph by PGE.
        They required 2 grounds for the pad-mount transformer.

        Their "Green Book" specified the type of clamp.

        I wanted to CADWELD the wire to the rod. They didn't want to accept that and could not explain why.

        I did "when in Rome" and clamped the wire AND then CADWELDed it too.

        But I still wonder -- why wouldn't they want a welded connection?
        more and more, i've seen specifications that want a compression connection,
        and they want to be able to see the die number witness on the fitting.

        in other words, burndy 12 ton press, and burndy dies. not universal, which i think
        is a bunch of hooey, but it's 'cause the harbor freight crimpers that are metric, and
        don't get things stuck together well enough.

        it's been almost 10 years since i did a cadweld.
        ~New signature under construction.~
        ~~~~Please excuse the mess.~~~~

        Comment


          #5
          Originally posted by Open Neutral View Post
          ...

          Their "Green Book" specified the type of clamp.

          I wanted to CADWELD the wire to the rod. They didn't want to accept that and could not explain why.
          ...
          Seems obvious that the only explanation they felt was needed was 'it's not in our book'.

          Comment


            #6
            Originally posted by Open Neutral View Post
            Thanks; I'd never heard of such.
            bob always comes up with amazing stuff.
            anywhere in article 500, that is who i'd listen to, if i needed an answer...
            well, one that was correct, that is.
            ~New signature under construction.~
            ~~~~Please excuse the mess.~~~~

            Comment


              #7
              IEEE 142/2007 Green Book
              4.3.3 Connecting to electrodes
              Connections to electrodes are usually made by one of several means: mechanical, fusing,
              or compression. The first of these methods, mechanical fittings, is best suited for making
              connections to ground as the fittings are often easily disconnected, allowing for periodic
              ground-to-earth measurements.

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                #8
                My perspective is the biggest threat to a good ground is a corroded connection, 20 years after the fact. That's why I preferred welded connections.

                I'm puzzled that the standards folks are seemingly unconcerned about that.

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                  #9
                  Are there not also concerns about toxic byproducts resulting from the process of exorthermic processes such as cadwelding?

                  Comment


                    #10
                    Originally posted by Julius Right View Post
                    IEEE 142/2007 Green Book
                    4.3.3 Connecting to electrodes
                    Connections to electrodes are usually made by one of several means: mechanical, fusing,
                    or compression. The first of these methods, mechanical fittings, is best suited for making
                    connections to ground as the fittings are often easily disconnected, allowing for periodic
                    ground-to-earth measurements.
                    Easily disconnected, allowing for periodic
                    ground-to-earth measurements[
                    Comments based on 2017 NEC unless otherwise noted.

                    Comment


                      #11
                      I like it! Thanks for pointing that out.

                      Comment


                        #12
                        I'd rather be able to disconnect/reconnect somewhere above ground [say under the transformer cover] where it is visible and accessible, but OK.

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