Wires and wiring

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goingtoghana
goingtoghana Solar Expert Posts: 34 ✭
in Solar Beginners Corner #1
Thanks to your great help, I am all set with ordering the right components with one exception. Wires and wiring. What I want is a reference for what type of wire I need to purchase and how should it be contained or wired from the panels to the combiner. I know the gauge and I am going to use the MC4 connectors, but is there a particular wire I should be going after to meet "code" for PV installs? What should that wire be contained in coming from the panel to the combiner?

I am going to have this is Africa, so no U.S. codes, but I still want to do this correctly as if it were. youtube is a disaster trying to find good information on this one topic.

Thanks
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,443 admin
    #2
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    Re: Wires and wiring

    Several issues...
    • Temperature--Wire runs on roofs need a high temperature rated insulation.
    • Wet Locations--Obviously rain/exposure
    • UV Rating--The transistion from array to combiner box wiring should be rated for sun exposure
    • Buried--If you run the wires in a trench--there is wiring rated for direct burial
    • Conduit--I like to recommend several large conduits for burial--Makes it easier to add to the array and/or bring other wire out to the array location (communications, AC power for patio, well/pumping, etc.). Leave extra pull wires/rope in conduit so the next pulls are easier--Also over sized conduit with "soft bends" or several 45 degree bends instead of hard 90 degree bends are easier to pull too.

    For US, our host NAWS uses: All MC cables are made with #10 AWG stranded UL/NEC approved RHW-2/RHH (USE-2) sunlight resistant wire.

    You should be able to ask your local electrical warehouse for help (or an electrician/local building code manual--In the US we usually use the "NEC"--National Electric Code).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • goingtoghana
    goingtoghana Solar Expert Posts: 34 ✭
    #3
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    Re: Wires and wiring

    Since this will be a short run from the roof to the charge controller, should I run conduit from the roof or can the wires just be tied together?
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #4
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    Re: Wires and wiring

    what is the risk level of someone pilfering the wires? Conduit can be a slight deterrent.
     
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #5
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    Re: Wires and wiring
    westbranch wrote: »
    what is the risk level of someone pilfering the wires? Conduit can be a slight deterrent.
    High DC voltage can be another deterrent. :-)
    SMA SB 3000, old BP panels.
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  • goingtoghana
    goingtoghana Solar Expert Posts: 34 ✭
    #6
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    Re: Wires and wiring

    Which is why I ask. a) would it be required in the U.S. b) what "type" of conduit?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,443 admin
    #7
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    Re: Wires and wiring

    Many "service station" with GT solar panels simply use a weather head and three wires draped through the air (just like the AC feed from the power pole to your main panel in many countries)... In fact, you can probably use the same wire (sun/wet rated). In the US, they many times use Aluminum these days (need heavier wire vs copper) and need special compression fittings/greases to join the copper to aluminum wiring at both ends (aluminum corrodes very easily if not properly prepared and/or wrong electrical hardware is used).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #8
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    Re: Wires and wiring

    it seems to me that if there is the possibility of vandalism that the choice of going to conduit would be obvious, but i would probably take it one step further and use a strong metal piping. this may or may not be viable there and if somebody really wants to do damage they will most likely go after the pvs if they could'nt do in the wiring. this means forget u.s. requirements as you may need something heavier than conduit.

    in light of the newer gold mining series out it led me to believe the possibility of this being at a mining operation is strong and leads me to believe extra precautions may be needed for the install if this is the case and is my reasoning for addressing the vandalism.
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