Salt Air Resistant Rooftop Junction/Transition Box

I am doing the system design and installation for a large PV system at a sea-side home in the Caribbean.

Aluminum, galvanized, or powder coated roof-top junction/transition boxes are not acceptable to the roofing contractor. He wants either UV resistant PVC or stainless steel.

The J-Boxes must be low profile, fit under a Unirac SunFrame array using 3" standoffs, and have integrated flashing if possible.

Each J-Box must be big enough to handle 4 PV strings. Internal 6" Din rail mounting is desirable. My initial recommendation was the SolaDeck, which would be acceptable to the roofer if available in PVC or stainless steel.

Any recommendations from other installers?


  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Salt Air Resistant Rooftop Junction/Transition Box

    3" clearance above the roof is sort of low for best power production. I guess a trade off between that, and hurricane uplift.

    SS NEMA boxes ? A google search turned up a bunch of them but they are pricey.
    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

    gen: ,

  • Icarus51
    Icarus51 Registered Users Posts: 2
    Re: Salt Air Resistant Rooftop Junction/Transition Box


    Thanks for the reply! Yes, 3" was selected to minimize uplift since the site is in "hurricane alley". I'll google your suggestion - but price is not the driver on this project. It has to be solidly constructed and built to last.

    I'm looking for something specifically designed for solar application, and hopefully some others on the board can suggest product(s) they've used in the past.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Salt Air Resistant Rooftop Junction/Transition Box

    ss is nice, but i know plastic boxes exist too.