MC connectors and wiring in parallel

Keet
Keet Registered Users Posts: 7 ✭
in PV Installers Forum - NEC, Wiring, Installation #1
So I'm onto the next phase of trying to design the wiring for my array.
I've taken the Isc of the panels and multiplied it by the 1.56, then divided the fuse rating by the number,
it gave me 3.74, so I should be able to parallel 3 panels and stay under the fuse rating, correct?

The next part is what is the best method to connect the panels in parallel;
There are MC connectors you can buy that are 2:1, or 3:1 or,
Can I bring them into a junction box and wirenut them together before going on to the fuse panel? (this is fairly low current, <7A)
Just trying to figure out a way to reduce cost a bit without having to buy a huge fusebox and 12-16fuseholders n fuses

Thanks!
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Comments

  • n3qik
    n3qik Solar Expert Posts: 741 ✭✭
    #2
    Re: MC connectors and wiring in parallel

    To be NEC complaint, each panel will need is own fuse.
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  • Keet
    Keet Registered Users Posts: 7 ✭
    #3
    Re: MC connectors and wiring in parallel

    But I thought as long as you remain under your panel and conductor current limits you could parallel them?
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  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    #4
    Re: MC connectors and wiring in parallel
    Keet wrote: »
    But I thought as long as you remain under your panel and conductor current limits you could parallel them?

    Few panels have a maximum allowed current of 3X of there ISC ( short circuit current ) rating

    Look at the rating of your panel, the maximum current should be listed and that will be what limits what you can parallel without additional fuses.
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  • n3qik
    n3qik Solar Expert Posts: 741 ✭✭
    #5
    Re: MC connectors and wiring in parallel

    Nope. The logic to fusing each one, is if one panel shorts out, the rest could/will feed into their max current into that shorted panel.

    This is also true if you parallel more than two batteries.
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  • Keet
    Keet Registered Users Posts: 7 ✭
    #6
    Re: MC connectors and wiring in parallel
    Solar Guppy wrote: »
    Few panels have a maximum allowed current of 3X of there ISC ( short circuit current ) rating

    Look at the rating of your panel, the maximum current should be listed and that will be what limits what you can parallel without additional fuses.

    ISC is 1.19
    Fuse rating on the back of the panel says 5A
    isn't 3 panels x1.19 <5A ?
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  • Keet
    Keet Registered Users Posts: 7 ✭
    #7
    Re: MC connectors and wiring in parallel
    Solar Guppy wrote: »
    Few panels have a maximum allowed current of 3X of there ISC ( short circuit current ) rating

    Look at the rating of your panel, the maximum current should be listed and that will be what limits what you can parallel without additional fuses.

    Ok, so can I do 2 panels and a 3A fuse?
    If a short happens in one of the panels, the fuse would only let 3A in before popping,
    and the other panel in parallel with it being 1.19A Isc,
    would still be less then the 5A rating, yes?

    Thanks for your patience.
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