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Penetration into roof via junction box?

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  • #16
    > I think if I rotate the JB 45degrees so it's angled downstream of the roof, it'll help it not "catch" water

    That will help, and if your sealing goop is protected from the worst of the weather by a panel, thats good too. Maybe put some anti-size on that panel's mounting hardware so you can get it out easily.
    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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    • #17
      That is a good call and I ALWAYS try to use anti-seize compounds on hardware. Electrical connections often too (although not little splices - more like lugs and stuff) I work in a lot of nasty industrial environments and that stuff has saved my ass more times than I can count. Thank you for the reminder - I'll put it on my packing list to make sure it goes with me for the install.

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      • #18
        Originally posted by Xplode View Post
        It's still a penetration of about the same size....
        Sounds like you have to have a penetration of a ~1.5" conduit.
        It's just how are you going to keep that penetration watertight.
        Is it going to go up into a Jbox? And the jbox has a rubber seal compressed between the jbox and the roof, keeping that penetration waterproof? (along with some caulk that helps keep the jbox tight in place and helps with waterproofing?


        Or is it going to be a 1.5" or 2" conduit going up to a weatherhead? or over to a jbox? or over to gland(s)?
        And the weatherproofing for the roof penetration is standard boot type weatherproofing.
        Then the weatherproofing for the inside of the conduit is handled by the weatherhead/jbox/gland(s).

        I think either approach for weatherproofing the penetration is viable. I'd probably go with the one I think I'd be more comfortable with executing.

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        • #19
          Well I went for it this past few days... Got the system turned on today. Ended up not being able to turn the box diagonally due to the profile of the roof. but with the amount of QuadMAX i used, I feel pretty confident it'll stay watertight for years to come. if it doesn't, I have access to the underside of the penetration through the soffit material below, so I'll be able to see what's going on. The racking/panels are also only 2 feet from the peak of the roof, so minimal water should end up running at the box as well.
          Due to some crappy service and poor stock choices from the local shop in BC here, I ended up with 300Watt Canadian Solar panels instead of the 280W I originally wanted, but the sales guy was kind enough to mark them down considerably for me ($250CDN/panel instead of $300CDN).

          IMG_20180806_145645935.jpg
          I probably could have centered the hole in the box a bit more, but I was thinking about how stiff the #10AWG PVU wire is, and wanted to have it be able to lay down in the box nicely. The two screws on the uphill side actually grab into the roof supports below, so the side that will see water flowing at it is cinched down tight to the roof. I sealed around the hole on the roof, and then again around the end of the box, plus the screws themselves were coated before install, and then around the screws where they are exposed as well.


          IMG_20180808_093423154.jpg
          After much reading and people not being keen on using wire-nuts for the splice (transitioned to teck90 cabling to get to the breaker down with the charge controller), I used some insulated terminal strip, but honestly I think wire nuts are probably more solid... I may go back and change it later. Panels are only capable of up to 9.8A max, so the #10awg should handle it with no heat at the joint. The cables enter the box from the downhill side, and I ended up picking up a 3/8NPT tap and just drill/tap the box instead of using the nuts. Should improve the sealing.

          Normally I'd make the sealant look a little nicer, but in this case you can't see it (panel over top of it) and I just wanted lots of sealant to make sure it holds.

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          • #20
            Is the hardware on the L brackets and rails , Stainless ? I hope so.

            I can't tell, which is the uphill side, but the downhill side should have minimal goop, so any leakage water, can drain away and not be trapped under the L or the box
            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


            • #21
              Originally posted by Mike90250 View Post
              Is the hardware on the L brackets and rails , Stainless ? I hope so.

              I can't tell, which is the uphill side, but the downhill side should have minimal goop, so any leakage water, can drain away and not be trapped under the L or the box
              Yes to all of it. The fastener hardware is all stainless, I've also used anti-oxidation compound on all the fasteners, as well as the grounding connections, and I put a complete ring around the penetration underneath the box, but horseshoe shaped sealant around the outside edges of thebox... ie there isn't a bead across the downhill side of the box (it's the side under the black nylon glands)

              The L Brackets are actually mounted using stainless hanger bolts with a rubber seal. It was what was suggested to me by the suppliers, although I have since found out that Kinetic has some other options. Didn't love the look of the seal and didn't trust it to survive a decade or two of -20C to +40C so I sealed the actual penetration with quadMAX and then coated the whole thing up to the shank of the stainless bolt again. I'm not normally an over-sealer kind of guy, but I really don't want to have this thing leak and make me look like an ass to the family.

              IMG_20180806_125210134.jpgIMG_20180806_125216148.jpg
              Last edited by Xplode; 08-09-2018, 02:49 AM.

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