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    Electrode sizing

    For a 200 amp service, resi., 5/8 by 8' is required. Does a 400amp/320 continuous service require a 3/4 by 10' electrode? I feel like this was something that I had heard about. TIA!

    #2
    Originally posted by C_Hill View Post
    For a 200 amp service, resi., 5/8 by 8' is required. Does a 400amp/320 continuous service require a 3/4 by 10' electrode? I feel like this was something that I had heard about. TIA!

    No, the service can be 6000 amps and the ground rod only needs to be 5/8" x 8' or 1/2" by 8' if listed. BTW, welcome to the forum
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky

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      #3
      Thanking you, Sir.

      Comment


        #4
        How many rods are you installing?
        Rob

        Moderator

        All responses based on the 2017 NEC unless otherwise noted

        Comment


          #5
          Code Reference

          But Where in the NEC does it reference the size and depth of the Ground Rod?

          Comment


            #6
            Originally posted by ManofSteele View Post
            But Where in the NEC does it reference the size and depth of the Ground Rod?

            Here for one

            250.52(A)(5) Rod and Pipe Electrodes. Rod and pipe electrodes shall
            not be less than 2.44 m (8 ft) in length and shall consist of the
            following materials.
            (a) Grounding electrodes of pipe or conduit shall not be
            smaller than metric designator 21 (trade size 3∕4) and, where of
            steel, shall have the outer surface galvanized or otherwise
            metal-coated for corrosion protection.
            (b) Rod-type grounding electrodes of stainless steel and
            copper or zinc coated steel shall be at least 15.87 mm (5∕8 in.) in
            diameter, unless listed.

            Also

            250.53(G) Rod and Pipe Electrodes. The electrode shall be installed
            such that at least 2.44 m (8 ft) of length is in contact with the
            soil. It shall be driven to a depth of not less than 2.44 m (8 ft)
            except that, where rock bottom is encountered, the electrode
            shall be driven at an oblique angle not to exceed 45 degrees
            from the vertical or, where rock bottom is encountered at an
            angle up to 45 degrees, the electrode shall be permitted to be
            buried in a trench that is at least 750 mm (30 in.) deep. The
            upper end of the electrode shall be flush with or below ground
            level unless the aboveground end and the grounding electrode
            conductor attachment are protected against physical damage as
            specified in 250.10.
            They say I shot a man named Gray and took his wife to Italy
            She inherited a million bucks and when she died it came to me
            I can't help it if I'm lucky

            Comment


              #7
              Originally posted by C_Hill View Post
              For a 200 amp service, resi., 5/8 by 8' is required. ...
              Not if the rod is listed.

              Comment


                #8
                Originally posted by jaggedben View Post
                Not if the rod is listed.
                If you want to go one step further you could say that rods are never required.
                Rob

                Moderator

                All responses based on the 2017 NEC unless otherwise noted

                Comment


                  #9
                  Got it, Thanks

                  Comment


                    #10
                    In what situations one might install 3/4 by 10' ground rod instead of 5/8 by 8' ground rod?

                    Comment


                      #11
                      Originally posted by hhsting View Post
                      In what situations one might install 3/4 by 10' ground rod instead of 5/8 by 8' ground rod?
                      To meet some silly job spec.
                      Ethan Brush - East West Electric. NY, WA. MA

                      "You can't generalize"

                      Comment


                        #12
                        Originally posted by hhsting View Post
                        In what situations one might install 3/4 by 10' ground rod instead of 5/8 by 8' ground rod?
                        When I was a helper, our boss (mom'n'pop shop) always had us drive 3/4" RGS as electrodes . . . with a sledge hammer.
                        Master Electrician
                        Electrical Contractor
                        Richmond, VA

                        Comment


                          #13
                          Originally posted by hhsting View Post
                          In what situations one might install 3/4 by 10' ground rod instead of 5/8 by 8' ground rod?
                          The customer has the money and asked for it.
                          Its the only rod you have on the truck.
                          Job specs.
                          You’ve had it in the shop for years and are tired of looking at it because you are reminded of that one and only time you goofed up?
                          Tom
                          TBLO

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