beginner's grounding question

marijntje
marijntje Registered Users Posts: 2
in Solar Beginners Corner #1
Hi all. I am a Joe Homeowner and took on installing our 2.4 Kw grid tie system myself. It is a ground mount system built about 160 feet from the main panel where the DC disconnect, inverter (SMA Sunnyboy 2500) and the AC disconnect are placed. I have found out I have a lot to learn about electricity and have a question regarding grounding:
Can I connect the Inverter and AC disconnect grounding to the existing main panel grounding rod or do I need to run a ground wire from the inverter and disconnect to the (lightning) ground rod that I have at the rack and that is connected to the panels, rails and ground rack?

Thanks so much for reading this. All input greatly appreciated!
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  • tons001
    tons001 Solar Expert Posts: 71 ✭✭
    #2
    Re: beginner's grounding question

    You can and should connect the inverter and ac disconnect to main service entrance ground. You should also connect the main service entrance ground to the lightning ground at the array but do not bring that connection through your home! I accomplished this with a bare 6awg solid copper in a shallow trench between my service entrance ground and the array ground. You might want to consider throwing some lightning protection at your combiner box and at your dc/ac disconnects.

    There are people way smarter than I could hope to be on here so they may have more to add.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #3
    Re: beginner's grounding question

    Welcome to the forum.

    I suspect I will regret asking this but ... didn't your inspector tell you how the ground must be connected?

    All of the inverter's AC wiring, including the ground, is connected to the main service panel. This electrical safety ground is not lightning protection and has no bearing on the panel frame/mount grounding (although the inspector may not understand that). In this instance the two ground points should not need to be connected.
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  • marijntje
    marijntje Registered Users Posts: 2
    #4
    Re: beginner's grounding question
    Cariboocoot wrote: »
    Welcome to the forum.

    I suspect I will regret asking this but ... didn't your inspector tell you how the ground must be connected?

    All of the inverter's AC wiring, including the ground, is connected to the main service panel. This electrical safety ground is not lightning protection and has no bearing on the panel frame/mount grounding (although the inspector may not understand that). In this instance the two ground points should not need to be connected.

    Thank you for the information! Unfortunately during the first inspection I was at my real job and my father-in-law who was helping me with the construction of the rack met with the inspector. He did not get the impression that the inspector was particularly knowledgeable on this subject. Your answer is helpful though and I am pretty sure that I will not be running a ground over the entire length (160 ft) from the inverter to the rack and instead ground it to the main ground.
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