Roof Junction box

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System
System Posts: 2,511 admin
in PV Installers Forum - NEC, Wiring, Installation #1
All all, New here, 1rst post. I'm looking at installing a 5kw Enphase system with 230w REC panels on my roof. I think I have most of it planned out well but I really don't know how to run the conduit up through the roof into a j box. I would like to have the roof penetration directly underneath the j box. Any products or pictures out there that would help me? Also, since I have to run 2 branches, how is it done? Is there a double disconnects out there that I should use or do I need to have 2 separate runs of conduit into 2 disconnects? Any help would be greatly appreciated!!!


Thanks!!

John
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  • n3qik
    n3qik Solar Expert Posts: 741 ✭✭
    #2
    Re: Roof Junction box

    Look at this:

    http://www.rstcenterprises.com/pdf/soladeck_brochure.pdf
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  • System2
    System2 Posts: 6,290 admin
    #3
    Re: Roof Junction box

    Thanks Ken, Exactly what I was looking for!

    John
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  • n3qik
    n3qik Solar Expert Posts: 741 ✭✭
    #4
    Re: Roof Junction box

    Glad to help.

    .............................
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  • jimwilks
    jimwilks Registered Users Posts: 7 ✭
    #5
    Re: Roof Junction box

    In the picture which Ken provided the link to, there are small cord grips for each of the outgoing PV wires. Regular cord grips from any electrical supplier are much larger than this.

    Where do I get these small cord grips?

    Jim
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  • n3qik
    n3qik Solar Expert Posts: 741 ✭✭
    #6
    Re: Roof Junction box

    Look at Newark.com, 601 found.

    http://www.newark.com/conduit-fittings?isRedirect=true
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  • dwh
    dwh Solar Expert Posts: 1,341 ✭✭✭
    #7
    Re: Roof Junction box

    Any electrical supply shop will have them in various sizes and types.
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  • jimwilks
    jimwilks Registered Users Posts: 7 ✭
    #8
    Re: Roof Junction box

    Thanks very much!

    Jim
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  • CVN-71
    CVN-71 Solar Expert Posts: 54 ✭✭
    #9
    Re: Roof Junction box

    I used the Soladeck for my installation and it's excellent, easy to put in, easy to wire.
    I didn't use it as a combiner though, rather just as a pass-thru to the combiner directly beneath it in the attic.
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  • pbartko
    pbartko Solar Expert Posts: 37 ✭✭
    #10
    Re: Roof Junction box

    I'll second the recommendation for the SolaDeck. I used it on my progect, and it worked great. Very easy to install and has an integral flashing.

    Pete B
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  • SolarJoe67
    SolarJoe67 Registered Users Posts: 3 ✭
    #11
    I agree, for shingled roof, soladeck can't be beat. BUT, you will also require TWO branch circuits, each going to a 20A 2 pole breaker for your 5KW system, since each "String" (in this case RUN of TRUNK CABLE) can be no more than 16 of the M250 inverters. That means two runs of romex from the breaker box to the roof. There's enough room in the soladeck box for TWO sets of transition wiring from trunk cable to romex. Be sure to order an extra "drop" on each trunk cable to make sure you get the extra LENGTH you need to get to the jbox from each trunk cable end point!! Sometimes they cut the trunk cable as short as 12 inches!!  With TWO trunk cables, you have to END each of the 2 cables close enough to the Jbox to get in and have some length left to do the terminations!!
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  • SolarJoe67
    SolarJoe67 Registered Users Posts: 3 ✭
    #12
    Also, don't forget, when you are running that romex through the attic, you MUST keep it at least 10 inches below the roof surface and support it every 36 inches (or closer).
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #13
    And keep the wire gauge large enough you don't get voltage differential that over-volts the micros.  [ 260V on the roof, 240V at the meter because 12ga was "safe" ]
    Powerfab top of pole PV mount | 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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