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  • grounding and anodizing

    I'm a bit confused about something. As I understand it, the frames of solar panels are generally made from anodized aluminum, which does not conduct electricity. Yet it seems that many grounding strategies rely on contact with and between anodized surfaces.

    Take IronRidge, for example. Their rails are anodized, and the anodized panel frames lay against the rails. The "UFO" bolts, which clamp the panels against the rails, are stainless, and it's possible the rail is not anodized inside the groove where the UFO connects; but the UFO still clamps against the anodized panel frame. And this system is considered robust enough that they require only one grounding lug per row of panels.

    Specifically I don't see how an electrical connection is made between the panel and the rail. I must be missing something.

  • #2
    Most of the ground clips, or panel clips have teeth or lock washers that scrape or dig into the panel frame which allows for the ground.

    In the first two images the "teeth" are not that obvious, they are just little nubs on the square washer between the rail and the panel in the first image, and nubs on the round washer in the second image.. They are pretty obvious in the third image. the UFO clamps also have teeth on the UFO and on the frame T nut, last image.

    Weeb_grounding_clip.jpgScreenshot from 2019-11-20 17-33-46.png image_13172.jpg ironridge-universal-fastening-object-ufo-from-altEstore.com.png
    Last edited by Pir8radio; 11-20-2019, 07:47 PM.

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    • #3
      Originally posted by Pir8radio View Post
      Most of the ground clips, or panel clips have teeth or lock washers that scrape or dig into the panel frame which allows for the ground.
      Ok, I guess on the bottom of the clamping washer on the IronRidge UFO, there are teeth of a sort. I didn't think it'd be cool to scratch thru the anodization layer, because of corrosion, but I guess it's still aluminum under there.

      But I'm not actually using IronRidge, gonna go with a more ad-hoc (and cheaper) system using stainless-steel hardware and pressure-treated frame (this is ground-mount). So I guess as long as I have a toothed washer that gets forcefully pushed into the panel frame, I'm good.

      But I'd rather the grounding happens completely separately from the clamping, and I believe the grounding clip mentioned in the Talesun TP660 panels' installation manual
      (https://webosolar.com/store/en/pv-gr...p-1954381.html) accomplishes this. I'm not exactly clear where they intend for it to be installed on the panel frames: this (un)helpful picture doesn't help.

      Screen Shot 2019-11-20 at 6.44.31 PM.png
      Hopefully it can go on the bottom lip, and not on the edges of the panel (since that would get in the way of clamping arrangements). The clip appears to be 20mm wide, and it looks like the li is 35mm minus 11mm wide, so I guess that'll work.

      Screen Shot 2019-11-20 at 6.57.55 PM.png
      Last edited by RShackleford; 11-20-2019, 10:13 PM.

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      • #4
        Originally posted by RShackleford
        All I tried to do was to edit this post to make it clearer. And it's flagged again. This is exasperating.
        its automatic... to keep people from posting inappropriate things. the admins will approve it just wait for that...

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        • #5
          Originally posted by Pir8radio View Post

          its automatic... to keep people from posting inappropriate things. the admins will approve it just wait for that...
          I know, but I'm afraid to put the effort into editing any of my posts to make them clear (and this stuff can get fairly complicated), because it may just get lost.

          Can't people who've been here awhile be deemed "safe" ? If it turns out I'm not, I can be suspended or banned ...

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          • #6
            I went the same route (wood frame), My panels had little pre-drilled ground holes, which I assume most panels do. These holes accept the standard green grounding self taping screws
            shopping.png41D8Eymz43L._SX342_.jpg
            I just used those with the ground lugs and grounded every panel.

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            • #7
              Post approved. If I edit my own posts 2x in a row, they get flagged for moderation (but I can fix that for now)
              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

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              • #8
                Originally posted by Mike90250 View Post
                Post approved. If I edit my own posts 2x in a row, they get flagged for moderation (but I can fix that for now)
                Yea... I do that all the time, I'm click happy... I post, then read my own post, and find a word I misspelled, correct, update, read again find something else...

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                • #9
                  Originally posted by RShackleford View Post

                  I know, but I'm afraid to put the effort into editing any of my posts to make them clear (and this stuff can get fairly complicated), because it may just get lost.

                  Can't people who've been here awhile be deemed "safe" ? If it turns out I'm not, I can be suspended or banned ...
                  You won't get banned. The Anti Spam software will automatically put a post with multiple website links into review. It doesn't matter who makes the post.

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                  • #10
                    Originally posted by Pir8radio View Post
                    Most of the ground clips, or panel clips have teeth or lock washers that scrape or dig into the panel frame which allows for the ground.

                    In the first two images the "teeth" are not that obvious, they are just little nubs on the square washer between the rail and the panel in the first image, and nubs on the round washer in the second image.. They are pretty obvious in the third image. the UFO clamps also have teeth on the UFO and on the frame T nut, last image.

                    image_13172.jpg
                    The "teeth" on that third image DO NOT pierce the anodization of the module frames. That lug is aluminum, and the anodized coating on the frames is actually harder than the aluminum itself. The teeth are only there to make it look more aggressive.

                    If you are mounting directly to wood, you will need to run a wire to each module. Your best bet is to just use a standard lay-in lug. Just make sure it is tin plated and has a stainless steel screw.


                    Originally posted by Pir8radio View Post
                    I went the same route (wood frame), My panels had little pre-drilled ground holes, which I assume most panels do. These holes accept the standard green grounding self taping screws
                    shopping.png41D8Eymz43L._SX342_.jpg
                    I just used those with the ground lugs and grounded every panel.
                    Be advised, that most of those green ground screws are not designed for outdoor use. The green plating is a basic zinc coating that will start to corrode relatively quickly.

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                    • #11
                      The grounding, along with the wood to aluminum issue, are reasons I mounted the panels
                      to an aluminum rail, and bolted the rail to the wood. Here you can just make out the edges
                      of a square linoleum washer between where the aluminum bolts to the wood.

                      The rail was 66 feet long, which took 3 aluminum rail pieces. So the ground wire is run out
                      and connected to each piece. Bruce Roe

                      NSAjig.jpg

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                      • #12
                        Originally posted by emartin00 View Post

                        The "teeth" on that third image DO NOT pierce the anodization of the module frames. That lug is aluminum, and the anodized coating on the frames is actually harder than the aluminum itself. The teeth are only there to make it look more aggressive
                        huh... I didn’t realize some panel manufactures were hard anodizing frames. Plus those beam clamps are 6061-T6 hardened aluminum which should get through any anodizing, they are also rated UL 2703, so I hope they can get through it.

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