PV combiner box placement?

khotton
khotton Solar Expert Posts: 38 ✭
in General Solar Power Topics #1
Solar Experts,

My PV array will be 12 Kryocera 130GT panels wired 4 in series 3 parallel strings. PV is roof mounted on a flat roof using tilted UniRac mounts. I plan on using the MidNite Solar 3-breaker combiner box. The power panel will be about 30-feet away. My original thought was to run 3 sets of 10AWG MC cord to the combiner box wall mounted next to the power panel. However, I don't know if that is the best solution. Should I install the combiner box underneath the PV rack and then run single large wires (4AWG?) to the power panel. The combiner box is rated for outdoor use, but is it more convenient to have the breakers accessible indoors?

Also what type of conduit should I put the wire run in; or is just the exposed wire acceptable?

PS: what does it mean that the combiner box is without deadfront?

Kevin
· Share on Twitter

Comments

  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    #2
    Re: PV combiner box placement?

    Do the 3 home runs to a place that you can access the combiner for test and service. Also with copper prices out of site, the cost of 4awg will cost more than the more common 10awg
    · Share on Twitter
  • khotton
    khotton Solar Expert Posts: 38 ✭
    #3
    Re: PV combiner box placement?

    Thanks, Solar Guppy for your opinion. However, I am still hoping someone knows what a "deadfront" is on a combiner box.

    Kevin
    · Share on Twitter
  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    #4
    Re: PV combiner box placement?

    http://forums.mikeholt.com/archive/index.php/t-91496.html
    · Share on Twitter
  • Robin Gudgel
    Robin Gudgel Registered Users, Solar Expert Posts: 58 ✭✭✭✭
    #5
    Re: PV combiner box placement?

    A deadfront is a metal or plastic shield or plate that hides all the wiring behind it. In the case of our MNPV3, we created a custom plastic snap in sub panel. When the metal flip up cover is opened, you see the breakers, but are not exposed to the wires behind the deadfront. I believe we have the only combiners that have built in deadfronts. You can see the black deadfront on the right side of this ad.
    http://www.midnitesolar.com/mnpv3%20cheers%20lo%20res.pdf
    If the link doesn't work, go to www,midnitesolar.com and then to documents. It is very hard to justify the huge capital expense for a product that has very low profit. I did not spend the money for a deadfront for the PSPV or earlier Trace combiners and always regretted it. I also always wanted to make an outdoor enclosure that had a flip up cover. It has something to do with moving parts I guess? When the MNPV6 project came up, I went to Home Depot and bought an Eaton disconnect box. I was so impressed with their included plastic deadfront that I just had to do it for our combiners also. It really does give the combiners a very professional look and feel. People seem quite happy with them since we have trouble keeping them in stock.
    Thanks,
    Robin Gudgel
    · Share on Twitter
  • VolcanoSolar
    VolcanoSolar Solar Expert Posts: 56 ✭
    #6
    Re: PV combiner box placement?

    Funny, just the other day I was showing someone my system and when I pulled the cover off of the Outback combiner box noted that yes, all those live metal surfaces are right there to touch.

    Glad you're including the protection on the new model.

    - Ted
    · Share on Twitter

Categories