ac to dc ground

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bobdog
bobdog Solar Expert Posts: 192 ✭✭
in Solar Beginners Corner #1
Can I ground my AC ground to the same rod that my DC is grounded on? IN other words can I run all my grounds to the same ground point including the neutral/ground buss bar?

Tim
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,445 admin
    #2
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    Re: ac to dc ground

    As long as the DC ground is made in one location (at the ground rod for example)--It will be fine.

    What you don't want is for multiple paths (charge controller ground and a separate battery ground). This creates a parallel path for current and you don't know where the current is flowing.

    For example, you could get heavy return current through your 6 awg ground wire instead of your 2 gauge DC negative cable and over heat the smaller 6 awg wire.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #3
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    Re: ac to dc ground

    Tim,

    What Bill says but with a Caveat,,, I know that my neighbour had some trouble with a generator voltage control unit, that was not playing well with the PV system ground. If you do a search on this site, you will find a series of posts regarding a Mitusbishi genny, ground loops and DC grounding.


    The issue as I remember it was the PV negative was feeing back somehow to the AC voltage controller through the ground, causing the electronic control board to fail continually. My neighbour gave up and sold me the Genny for $50. I was finally able to track down the problem through a Mitsu rep, and they kindly enough sent me a new control unit. Not a bad deal for me anyway!

    I would do a search, but I am currently away, (as you know from off line conversation!) and I am too lazy right about now. A wee dram is calling,,,, LOL!

    Tony
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,445 admin
    #4
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    Re: ac to dc ground
    icarus wrote: »
    ... My neighbor had a Mitsubishi generator that would burn up it's voltage control about once a year. Each time, they said, "Yep, it's the control board, $400 please." After 3 times, my neighbor sold me the generator for $50 because he was so frustrated with it. I finally got ahold of Mitsubishi and they diagnosed the problem as a ground loop in the PV array, shorting out the DC side of the genset. (Something someone should have thought of after the first board, or perhaps the second) Mistusbishi did send me a new board after I reamed them about their dealers lack of understanding about the problem. I've found that T-Bay merchants aren't long on customer service. They seem to think that they are the only game in town. Now with the web we have choices than god...

    Does this generator have a DC output being used to charge the battery bank? Or is this an 120/240 VAC AC only output genset?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #5
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    Re: ac to dc ground

    Bill,

    The genset does have a 12vdc output, but it was never connected to any battery bank.

    There was an extensive conversation about this earlier,,,perhaps 3 years ago. I'll look for it when I get home if no one finds it sooner.

    T
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