Jerry, I'm curious, how did they prove over torquing? When doing inspections it's easy to find connectors that are under torqued but I haven't heard of a reliable way to check for over torque.
Thanks, Will On Mon, Sep 6, 2021 at 1:34 AM Jerry Shafer <jerrysgarag...@gmail.com> wrote: > 1/4" x 20 is no more the 10 ftlbs (120 inlbs) and a good 1/4" impact > should be able to get you over 30 ftlb. When you overtorq bolts and nuts > you put undue and irreversible stretching and or tearing of the material > not to mention warping or bending of the plates, and rails, loosening and > retorqing is a wait as if damage is done its done, the best solution is to > replace all the stressed hardware. I have seen unirac "T" bolts crack the > the rails with a bad result, so the question is how far do you want to dig > and risk to take. Regarding cracked glass, I have only seen this with > incorrect use of the clamps but over torqing will also crush the frames. I > have inspected arrays after high wind events that resulted in destruction > of the array and the manufacture in all cases used over torq as thier out > so warranty are only as good as the installers. > Jerry > NABCEP PV inspector > > On Sun, Sep 5, 2021, 8:56 PM Corey Shalanski <coreso...@gmail.com> wrote: > >> August, >> >> Thanks for your feedback.The racking model is EcoFoot2+ >> <https://ecolibriumsolar.com/ecofoot2plus/> by Ecolibrium Solar (now >> part of Unirac). These module clamps are also self-grounding with teeth to >> bite into the module frame. I reached out to the manufacturer, who >> confirmed that the clamp material is aluminum extrusion and the hardware is >> stainless steel. >> >> The modules were installed about 2 weeks ago, so not very much time has >> elapsed to be able to observe potential resultant damage. We haven't seen >> any problems so far. >> >> -- >> Corey >> >> >> On Fri, Sep 3, 2021 at 6:35 AM August Goers <aug...@luminalt.com> wrote: >> >>> >>> Hi Corey - >>> >>> For many years we used Pro Solar racking and Unirac Solarmount and >>> tightened the clamps with impact drivers. At some point maybe roughly 8 >>> years ago, Unirac switched its mid clamps to stainless steel self grounding >>> clamps with teeth to bite into the module frame. We continued to use >>> impacts with no issue. Then, starting around 4 years ago, we started to >>> have module glass failures with our SunPower commercial systems and these >>> Unirac clamps. We immediately switched to torque wrenches for tightening >>> the clamps. However, the failures continued. My guess is that the poor >>> design of the Unirac mid clamps in conjunction with thinner “weaker” module >>> frames exasperated the issue. We now have stopped using those mid clamps >>> and continue to hand tighten all clamps. We primarily install SunPower, and >>> their residential module frames have a lip so all the pressure from the >>> clamp doesn’t go to the glass. >>> >>> Getting to your question - what kind of mid clamps do you have? If they >>> are aluminum, there may be less risk than the stainless clamps. I would be >>> worried that the process of loosening and then re-tightening might cause >>> more damage than good if there aren’t any problems that have occurred to >>> date. It’s a good question. >>> >>> August >>> Luminalt >>> >> _______________________________________________ >> List sponsored by Redwood Alliance >> >> Pay optional member dues here: http://re-wrenches.org >> >> List Address: RE-wrenches@lists.re-wrenches.org >> >> Change listserver email address & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> There are two list archives for searching. When one doesn't work, try the >> other: >> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ >> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> >> List rules & etiquette: >> http://www.re-wrenches.org/etiquette.htm >> >> Check out or update participant bios: >> http://www.members.re-wrenches.org >> >> _______________________________________________ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > There are two list archives for searching. When one doesn't work, try the > other: > https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > http://www.members.re-wrenches.org > >
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