Naked ground wire

konstantin.neo
konstantin.neo Registered Users Posts: 19 ✭
in Solar Beginners Corner #1
When installing PV on the roof, is it ok to use naked wire for grounding the chassis?
I have 1" duct going from roof to the inverter panel, does the ground wire goes inside the duct with the other wires from PV's?
I am building a custom combiner box with Moeller DC breakers, bus bar for negatives and a bus bar for ground.
I was thinking about grounding each panel and combining grounds in the combiner box then to earth connection.
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Comments

  • jaggedben
    jaggedben Solar Expert Posts: 230 ✭✭
    #2
    Re: Naked ground wire

    Everything you say sounds okay. The answer to all your questions is yes. Only one thing... You may want to splice the bare wire from the array to a stranded wire that goes in the conduit. It will be easier to pull through the conduit and less likely to damage the other wires. It depends how big a wire it is.

    Sounds like English is not your first language.
    We usually say 'conduit' instead of 'duct'.
    We usually say 'bare wire' instead of 'naked wire.'
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  • konstantin.neo
    konstantin.neo Registered Users Posts: 19 ✭
    #3
    Re: Naked ground wire

    Oh I am using stranded wire for this, gauge 6, for the pv combiner to earth connection and from the main panel to earth. I think I'll be using 8 gauge for the individual PV frames.
    I was unsure if the wire goes inside the duct or on the outside.

    Oh and thanks on the terminology.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #4
    Re: Naked ground wire

    it might not be a good idea to have no insulation on it if the duct is anything other than copper or stainless steel for differing metals can create galvanic reactions (rust).
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  • ggunn
    ggunn Solar Expert Posts: 1,973 ✭✭✭
    #5
    Re: Naked ground wire
    niel wrote: »
    it might not be a good idea to have no insulation on it if the duct is anything other than copper or stainless steel for differing metals can create galvanic reactions (rust).
    Isn't it a code violation to run bare copper in conduit?
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  • jaggedben
    jaggedben Solar Expert Posts: 230 ✭✭
    #6
    Re: Naked ground wire
    ggunn wrote: »
    Isn't it a code violation to run bare copper in conduit?

    I don't think so. It is, however, a violation to run a solid conductor larger than 8awg inside a raceway.

    Bare copper contacting steel is not much of a concern. The real worry is copper contacting aluminum.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #7
    Re: Naked ground wire

    I believe it is against plumbing code for steel straps to contact copper plumbing... My building inspector made my contractor put plastic strips between steel straps and copper pipe--Said he has seen leaks at steel on copper contact points.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #8
    Re: Naked ground wire
    BB. wrote: »
    I believe it is against plumbing code for steel straps to contact copper plumbing... My building inspector made my contractor put plastic strips between steel straps and copper pipe--Said he has seen leaks at steel on copper contact points.

    -Bill

    Correct. The other alternative (more costly, of course) is to use brass or bronze straps or galvanized straps instead. (Or, of course, PEX pipe instead of copper! But that would not be really helpful in the case of wire.):-)
    SMA SB 3000, old BP panels.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #9
    Re: Naked ground wire

    Just to be clear, these were steel nailing shields behind dry wall--To prevent the accidental driving of a sheet rock nail or screw into the water pipes in the wall (same as used to protect wiring in walls too).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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