Panel Mounting on roof

bart
bart Solar Expert Posts: 30 ✭
in Solar Beginners Corner #1
I'm trying to plan where the panels and mount will be locate. I have a question regarding mounting at the top of the ridge. Can the panel end protrude past the ridge? Right now I have it plan so that there is only 9" at the bottom of the roof. I was wondering if I could slide the panels up the roof so there is around 30" at the bottom. However this would cause the top panels to protrude 21' past the roof's hip line. I hope I'm clear enough on my explanation - Here's a picture

RoofLayoutLandscape2.JPG.

Thanks, Bart

http://icpage.com/images/RoofLayoutLandscape1.JPG
http://icpage.com/images/RoofLayoutLandscape2.JPG
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Comments

  • n3qik
    n3qik Solar Expert Posts: 741 ✭✭
    #2
    Re: Panel Mounting on roof

    Go with #1 layout. With the panels above the roof line, wind will break the top row.

    Now before you even start, take drawing #1 to your local fire department and see if they have any problems with 90% of the roof covered with panels.

    Some departments like to see 30-40 inches of free space from the top of the roof so they can cut holes to vent the smoke out when there is a fire.
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  • bart
    bart Solar Expert Posts: 30 ✭
    #3
    Re: Panel Mounting on roof

    Thanks for the reply. Plan one it is. I did check with the city inspector about the "3 foot rule". They told it applies in commercial installs, but not residential and that the other side of hip line was open for the FD. I'm going to double check before I drill a ton of holes :)

    Bart
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  • solarix
    solarix Solar Expert Posts: 713 ✭✭
    #4
    Re: Panel Mounting on roof

    If I were you, I'd mount them portrait orientation because the mounting rails are going to be horizontal across your roof trusses right? Much better support for the rails that way. Makes the array 3 modules high which is 16.3 ft
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  • bart
    bart Solar Expert Posts: 30 ✭
    #5
    Re: Panel Mounting on roof

    Ok, trying portrait on paper. The only problem is that 3 need to landscape at bottom. Not sure it solves anything. I have 33 panels.

    Bart

    RoofLayoutPortrait.JPG
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  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    #6
    Re: Panel Mounting on roof

    I would stay with your first plan and share the rails between horizontal rows

    Also, try an get a 1-2" air gap between the panels horizontally, otherwise the lower rows can super heat the air that would have to travel all the way to the peak.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #7
    Re: Panel Mounting on roof

    Now slide the top row over the top of the hip
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #8
    Re: Panel Mounting on roof

    Why place the combiner way at the top, why not at the low end ?

    What about shade ? does your other section of roof shade the array evenly, or the top or bottom row first ? May want to fiddle with how panels are wired so shade only impacts a single string at a time, not all three at once.

    And you basic roof underneath, how old is it - is it worth considering rerofing before you install panels, or at least do the valley and the exposed lower parts before the panels go up.
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  • bart
    bart Solar Expert Posts: 30 ✭
    #9
    Re: Panel Mounting on roof

    I put the combiner at top because it was closet point to inverter. Luckily there is no shading problems. I had the roof inspected, so I we are OK there.

    Thanks for your input

    Bart
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,623 admin
    #10
    Re: Panel Mounting on roof

    Will the inverter get adequate shading and cooling? For every 10C (18F) you reduce operating temperatures, you roughly double the life of the electronics (20X = 2*2=4x longer life).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • bart
    bart Solar Expert Posts: 30 ✭
    #11
    Re: Panel Mounting on roof
    solar_dave wrote: »
    Now slide the top row over the top of the hip

    You think I'd be OK hanging over? I suppose I could secure end with long mounts, however it should be fair rigid mount to the rails

    Is there any code violation extending past the ridge somebody know of?

    Thanks, Bart
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  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    #12
    Re: Panel Mounting on roof

    You won't be able to meet the wind load requirements on the racking with having the panels over the peak. Uplift is bad enough but going over the peak and you have 100% of the wind energy being applied to the panels, for sure can't meet code on that idea
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  • bart
    bart Solar Expert Posts: 30 ✭
    #13
    Re: Panel Mounting on roof
    BB. wrote: »
    Will the inverter get adequate shading and cooling? For every 10C (18F) you reduce operating temperatures, you roughly double the life of the electronics (20X = 2*2=4x longer life).

    -Bill

    I believe so - The inverter is mounting on the north side

    Bart
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