Can you use both long and short side panel mounting points on the same panel?

HX_Guy
HX_Guy Solar Expert Posts: 296 ✭✭✭✭✭✭
in Solar Beginners Corner #1
Segway from my other thread and trying to possibly still use the racking that's been installed, it seems I would be able to keep the original layout and respect the fire code setback if I can use both the long side and short side to clamp down the panel. Per Canadian Solar's installs sheet, it says you can run railing parallel or perpendicular to the short or long side and the panel can be clamped between 7" - 10" from the edge on the short side and 13" - 22" on the long side.

panelmounting.jpg
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  • HX_Guy
    HX_Guy Solar Expert Posts: 296 ✭✭✭✭✭✭
    #2
    Re: Can you use both long and short side panel mounting points on the same panel?

    Additionally, can a common rail be used between two rows of panels?

    For example, can rail #2 in this diagram be omitted and that top panel mounted to rail #3? Or is rail #2 needed? Seems like overkill to have two rails with 4 mounting points for just one panel.

    panelmounting2.jpg
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #3
    Re: Can you use both long and short side panel mounting points on the same panel?

    Your first question: no reason why that would not work.

    Your second question: this would increase the loading on the rail mounts and may exceed ratings.
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  • HX_Guy
    HX_Guy Solar Expert Posts: 296 ✭✭✭✭✭✭
    #4
    Re: Can you use both long and short side panel mounting points on the same panel?
    Cariboocoot wrote: »
    Your first question: no reason why that would not work.

    Your second question: this would increase the loading on the rail mounts and may exceed ratings.

    Thanks Cariboocoot.
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  • HX_Guy
    HX_Guy Solar Expert Posts: 296 ✭✭✭✭✭✭
    #5
    Re: Can you use both long and short side panel mounting points on the same panel?

    Hmm, Canadian Solar apparently doesn't agree here. They said "We require modules to be fastened at a minimum of 4 points on two opposite sides. So mounting as you have proposed is not approved."

    Odd, I don't see why that wouldn't work but I actually can mount it on opposite sides like they specify so it's not a big deal.

    panelmounting3.jpg
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  • ramloui
    ramloui Solar Expert Posts: 109 ✭✭
    #6
    Re: Can you use both long and short side panel mounting points on the same panel?

    If you are located in an area where snow load is an issue, then I would definitely install per the manufacturer's recommendations because of the potential deflection stress it might put on the panel. High winds could also be an issue. Otherwise, I would not be worried.
    Off-grid cabin in northern Quebec: 6 x 250 W Conergy panels, FM80, 4 x 6V CR430 in series (24V nominal), Magnum MS4024-PAE
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  • HX_Guy
    HX_Guy Solar Expert Posts: 296 ✭✭✭✭✭✭
    #7
    Re: Can you use both long and short side panel mounting points on the same panel?
    ramloui wrote: »
    If you are located in an area where snow load is an issue, then I would definitely install per the manufacturer's recommendations because of the potential deflection stress it might put on the panel. High winds could also be an issue. Otherwise, I would not be worried.

    I'm the Phoenix area, so snow is not an issue. We do get some strong winds in the summer though, gusts of 40-50 MPH are not uncommon.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #8
    Re: Can you use both long and short side panel mounting points on the same panel?

    Because Canadian Solar has to cover themselves in respect to what load testing has actually been done in the lab. I doubt they ever tried this arrangement as it is unlikely to be necessary for a normal installation (yours is in a mess). So they can't legally say it will work if they've never tested it.

    It may also not pass inspection as it isn't to plan. Which they don't seem to care about except when collecting their massive fees and then coming along after the fact and disallowing whatever so they can collect more fees. Then they wonder why so many people skip the permits? :roll:

    So there you are up against the eternal conundrum: what will actually work from an engineering POV and what will pass legally are not always the same. In either direction. Hence the oft repeated advice around here that what matters isn't what works but what the AHJ okays.

    Sounds as though you are going to end up being your own installer. Obviously the original guy is no good, and very few contractors are willing to take on a job someone else started - and messed up.
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  • Organic Farmer
    Organic Farmer Solar Expert Posts: 128 ✭✭
    #9
    Re: Can you use both long and short side panel mounting points on the same panel?
    HX_Guy wrote: »
    Segway from my other thread and trying to possibly still use the racking that's been installed, it seems I would be able to keep the original layout and respect the fire code setback if I can use both the long side and short side to clamp down the panel. ...

    I used mounts on both long-side and short-side.

    I used three on each long side, and two on each short-side.

    It is okay to exceed the minimum. :)
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