grounding my solar panels....

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mark13
mark13 Registered Users Posts: 1
in Solar Beginners Corner #1
Im not a electrician ....... I just installed solar panels up on the roof, they are just 2 X 100 watts as a test ...... Do they need to be grounded ? If so how do I ground the panels when they are up on a roof ? I do see a ground spike where the pool filter is about a 100 feet away ....
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #2
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    Re: grounding my solar panels....

    even though it is for testing purposes only, i would still say it needs grounded. at a minimum use at least #8 copper wire from the pv frames in one continuous run to the ground rod. 100ft away is too far. you should have one around your utility meter. if this is not easy to get to or is also too far (say more than roughly 35ft away) then consider driving in a rod, even if a smaller one that is not nec approved, for a temporary ground. for a permanent install more measures that are proper should be followed, but your pvs are lightning rods and will attract it so some form of ground connection should be in place.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,447 admin
    #3
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    Re: grounding my solar panels....

    As Niel says, they do not need to be grounded to "work".

    However, they should be grounded for safety (both for lightning and static buildup, and if there is a broken panel/wiring)--And should be grounded if on roof/permanently installed.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
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    Re: grounding my solar panels....

    Dissenting opinion here.

    1). Grounding of PV frames/mounts or wiring does nothing for lightning protection really.
    2). Thousands of PV's are installed without grounds and without problems. RV installs for example.
    3). Two 100 Watt panels are going to be low Voltage (17-18 ) and low current (around 10 Amps together) so not much of a safety hazard to begin with. No worse than the average car electrical system.

    Ground them if you can, by all means. But don't worry yourself into a fit if it isn't feasible to do so.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #5
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    Re: grounding my solar panels....

    coot,
    here we can agree to disagree as i've seen what can happen from even a brief time of metal on a roof being ungrounded. the amount of metal there is about as much as the antenna i had up that had the ground wire accidentally cut through and within hours a storm came and the antenna i had was hit. the years previous with the ground intact it was never hit. the static buildup bill refers to can attract lightning and grounding often bleeds off that buildup.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #6
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    Re: grounding my solar panels....
    niel wrote: »
    coot,
    here we can agree to disagree as i've seen what can happen from even a brief time of metal on a roof being ungrounded. the amount of metal there is about as much as the antenna i had up that had the ground wire accidentally cut through and within hours a storm came and the antenna i had was hit. the years previous with the ground intact it was never hit. the static buildup bill refers to can attract lightning and grounding often bleeds off that buildup.

    Well yes, Niel. But when you've got a PV install you shouldn't expect grounding the frames to make that big a difference for lightning protection because you've still got a positive and negative 'antenna' waiting to pick up that SV. If you go for the ground, go for the SPD as well and then that's the best you can hope for.

    We get lots of lightning around here, yet rarely a strike on a cabin or house. Trees make a great lightning rods, and not just when they get hit; they sort of 'raise the ground' up to the sky and a lot of that SV goes away before it comes near your wiring.

    I have heard that a wide open field is the worst for a lightning strike because you may be the tallest thing in it. (Not recommending anyone experiment to find out.)
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #7
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    Re: grounding my solar panels....

    lightning does what it wants to as its lowest path of resistance is not always as you think it to logically be. at one time i lived in a narrow valley with many trees, wires, etc being much higher than my place at the time. i also had an antenna that was mounted about 30ft above a creek on a telescoping mast (about even with the apartment roof as my landlord did not want me to mount it on the building) and it was well grounded. the lightning hit a pole about 30ft away in spite of all of the better things for it to hit 500ft deep into the valley. i had no damage to my radio without a surge protector on it, miraculously. btw my radio coverage in that valley royally sucked.
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