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  • Irreversible splice+Junction Box

    Hi guys,
    I am new here so bare with me. I had an inspection today for a ground mount PV system. We failed because we did not use An irreversible splice inside the junction box. We have a continuous Bare copper run connecting the modules, rails, the structure and two ground rods located at the array that eventually runs into a junction box. The Bare copper was spliced with a split bolt to THHN and ran into the DC ground port in the inverter. Another ground was run from the AC port in the inverter into the Main service Panel. The MSP has its own ground rod and a uffer. My questions are:
    What code reference mandates an irreversible Splice inside of the junction box if any?
    Does a split bolt meet code requirement for the connection?
    If not, what type, make and model, of splice will work and where can i find them?

    Do the two ground rods at the array in any way merit slack on the rule for the ground to be continous?

    Thank you?

    Extra info-i believe we are covered under 690.47(C) for grounding type. Combined GEC to EGC by UL approved bonding jumper inside inverter.

  • #2
    rule #1 The inspector is ALWAYS right. He may not be correct, but always right.

    rule #2 Ground wires need to be either contiguous, or spliced with irreversible crimp or thermal fusion.
    Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister

    Comment


    • #3
      Originally posted by shocknocka View Post
      What code reference mandates an irreversible Splice inside of the junction box if any?
      That would be 250.64 (C)

      (C) Continuous. Except as provided in 250.30(A)(5) and
      (A)(6), 250.30(B)(1), and 250.68(C), grounding electrode
      conductor(s) shall be installed in one continuous length
      without a splice or joint. If necessary, splices or connections
      shall be made as permitted in (1) through (4):


      (1) Splicing of the wire-type grounding electrode conductor
      shall be permitted only by irreversible compressiontype
      connectors listed as grounding and bonding
      equipment or by the exothermic welding process.


      (2) Sections of busbars shall be permitted to be connected
      together to form a grounding electrode conductor.


      (3) Bolted, riveted, or welded connections of structural
      metal frames of buildings or structures.


      (4) Threaded, welded, brazed, soldered or bolted-flange
      connections of metal water piping.

      Originally posted by shocknocka View Post
      Does a split bolt meet code requirement for the connection?
      No

      Originally posted by shocknocka View Post
      If not, what type, make and model, of splice will work and where can i find them?
      H and C Taps available ate electrical supply warehouses. They require special tooling and training to install

      Originally posted by shocknocka View Post
      Do the two ground rods at the array in any way merit slack on the rule for the ground to be continous?
      No they are part of the Ground Electrode System as one unit
      MSEE, PE

      Comment


      • #4
        Thank you very much.

        Comment


        • #5
          Originally posted by shocknocka View Post
          Hi guys,
          I am new here so bare with me. I had an inspection today for a ground mount PV system. We failed because we did not use An irreversible splice inside the junction box. We have a continuous Bare copper run connecting the modules, rails, the structure and two ground rods located at the array that eventually runs into a junction box. The Bare copper was spliced with a split bolt to THHN and ran into the DC ground port in the inverter. Another ground was run from the AC port in the inverter into the Main service Panel. The MSP has its own ground rod and a uffer. My questions are:
          What code reference mandates an irreversible Splice inside of the junction box if any?
          Does a split bolt meet code requirement for the connection?
          If not, what type, make and model, of splice will work and where can i find them?

          Do the two ground rods at the array in any way merit slack on the rule for the ground to be continous?

          Thank you?

          Extra info-i believe we are covered under 690.47(C) for grounding type. Combined GEC to EGC by UL approved bonding jumper inside inverter.

          The irreversible splice rule is specific to the GEC. The reason they require it to be irreversibly bonded throughout all connections, is to guarantee that the inverter has a reference to derive its grounded DC conductor, no matter what anyone might do with ground bars on intermediate equipment. Irreversible splices are also a lot more resistant to thermal expansion cycles, than anything you assemble with a threaded fastener.

          A split bolt is reversible, a set screw is reversible, an insulation piercing connector is reversible. To make it irreversible, you need connectors that no one can undo with any tool (with the exception of outright breaking it).

          On simple residential systems, the combined EGC/GEC certainly makes sense to do. Gotta run the GEC, which well exceeds the size you need for an EGC.

          On larger systems exceeding 200A, combining them is just asking for trouble, to try and irreversbly crimp hundreds of kcmil. Run a #6 copper GEC irreversibly, and run your appropriately sized EGC in the manner that you would ordinarily route an EGC.i

          Comment


          • #6
            Originally posted by shocknocka View Post
            Do the two ground rods at the array in any way merit slack on the rule for the ground to be continous?
            The only slack you will get is that if you have two ground rods most inspectors and the majority of the code gurus will say that you only have to run continuous or irreversible to one of the two. The wiring joining the two is a bonding jumper which is not required to be continuous.

            Also note that for PV installations there may be rules which require an EGC connecting two points and other rules which require a GEC following the same path. In those cases the same wire can serve both purposes, in which case it has to meet the minimum requirements for both.
            SunnyBoy 3000 US, 18 BP Solar 175B panels.

            Comment


            • #7
              Originally posted by Mike90250 View Post
              rule #1 The inspector is ALWAYS right. He may not be correct, but always right.

              rule #2 Ground wires need to be either contiguous, or spliced with irreversible crimp or thermal fusion.
              rule #3, if the inspector is still wrong, see rule #1.

              Comment


              • #8
                Originally posted by J.P.M. View Post
                rule #3, if the inspector is still wrong, see rule #1.
                Actually I say yours is rule #2 and the contiguous ground wire is rule #3.

                Comment


                • #9
                  I also had to use an irreversible splice in my rooftop junction box between my #6 solid GEC and the THHN run down to the ground. I ended up using a Thomas and Betts 3ML30 c-tap, which I bought from Grainger. For the tool, I got myself a Harbor Freight hydraulic compression tool. It was able to make a nice and clean compression joint that the inspector approved. It has different size inserts for different size connections. The inspector had warned me not to use pliers and leave teeth marks as he would reject that.

                  Shocknoka, if you are in Southern California, I can let you use the hydraulic compression tool.
                  4kW DC solar w/microinverters, Chevy Volt

                  Comment


                  • #10
                    Originally posted by wrlsguy View Post
                    For the tool, I got myself a Harbor Freight hydraulic compression tool. It was able to make a nice and clean compression joint that the inspector approved.
                    Some inspectors will actually want to see the stamped marking left by the compression die that indicates that it was the right die for that particular brand and size compression connector.The Harbor Fright tool will not do that.
                    Luckily your inspector was not that obsessive.
                    SunnyBoy 3000 US, 18 BP Solar 175B panels.

                    Comment


                    • #11
                      Originally posted by inetdog View Post
                      Some inspectors will actually want to see the stamped marking left by the compression die that indicates that it was the right die for that particular brand and size compression connector.The Harbor Fright tool will not do that.
                      Luckily your inspector was not that obsessive.

                      I've got that same tool from Harbor Freight. All the dies are mislabeled, and one needs to use the die for the next larger size wire, if it is ever going to crimp. For #10 wire, I had to use the dies marked "#7". I've never heard of 7 gauge wire. A good way to use that scrap USE-2 wire, that keeps landing in the workshop.

                      It sure beats ratchet crimpers, when you've got two hundred rail splice grounding jumpers to make. Saves a lot of wrist pain, and it is much easier to undo any false starts.

                      I'm surprised that inspectors would have that much attention to detail, that they'd look for crimper die markings.

                      Comment


                      • #12
                        Originally posted by carultch View Post
                        I've got that same tool from Harbor Freight. All the dies are mislabeled, and one needs to use the die for the next larger size wire, if it is ever going to crimp. For #10 wire, I had to use the dies marked "#7". I've never heard of 7 gauge wire. A good way to use that scrap USE-2 wire, that keeps landing in the workshop.

                        It sure beats ratchet crimpers, when you've got two hundred rail splice grounding jumpers to make. Saves a lot of wrist pain, and it is much easier to undo any false starts.

                        I'm surprised that inspectors would have that much attention to detail, that they'd look for crimper die markings.
                        I also had to use a bigger die than marked. But I was able to pick one that fit the c-tap well and it made a great irreversible crimp. The inspector took my practice crimp as an example sample, so I know he liked it. He was very particular about having UL markings on the WEEBs and using a single brand of racking hardware..
                        4kW DC solar w/microinverters, Chevy Volt

                        Comment


                        • #13
                          Originally posted by inetdog View Post
                          Some inspectors will actually want to see the stamped marking left by the compression die that indicates that it was the right die for that particular brand and size compression connector.The Harbor Fright tool will not do that.
                          Luckily your inspector was not that obsessive.
                          I had located an official compression tool and die, but it was going to cost me more to rent for a day than buy the Harbor Freight tool. I was lucky, but the inspector was otherwise quite thorough, and I had more than my fair share of bad luck with the project prior to that point.
                          4kW DC solar w/microinverters, Chevy Volt

                          Comment


                          • #14
                            Originally posted by wrlsguy View Post
                            I also had to use an irreversible splice in my rooftop junction box between my #6 solid GEC and the THHN run down to the ground. I ended up using a Thomas and Betts 3ML30 c-tap, which I bought from Grainger. For the tool, I got myself a Harbor Freight hydraulic compression tool. It was able to make a nice and clean compression joint that the inspector approved. It has different size inserts for different size connections. The inspector had warned me not to use pliers and leave teeth marks as he would reject that.

                            Shocknoka, if you are in Southern California, I can let you use the hydraulic compression tool.
                            What was the exact tool you bought? I see hexagon dies at Harbor Freight.

                            Comment


                            • #15
                              Learn to say "Yes Boss, I does what you sez"
                              BSEE, R11, NABCEP, Chevy BoltEV, >3000kW installed

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