Grounding Array

solarhungrysolarhungry Registered Users Posts: 29 ✭✭
I have a bit of time looking for this answer but seems to be complex as the answers are going everywhere. 
Getting ready to ground my panels that's on unistrut.  I am deciding on using Weeb Lug 6.7AS for the grounding. I have 8 panels that will be in series of 24 volt.  Do I have to ground each panel still? Or just 4 of them since 2 in series are acting as 1? 

Also I am reading when I ground my panels ,the ground wire goes to the bus bar inside the combiner box . Which then 1 ground wire goes out of the combiner box to my 8 foot ground  rod which is next to the array.  And another wire  from the ground bus  goes to the house where I'll have another ground rod for my equipment. (Inverter,batteries, controller, and ect.)  It's about 100 feet run from array to house/inverter. Regardless how far the run is ,I still have to connect that solar array ground with the equipment ground  rod?  In the help section on this Web site  I've seen the diagram of the wiring of a combiner box. My combiner box is on it's way, I just thought I try and get a head start.  "Instructions included with combiner box "  Thanks! 


  • BB.BB. Super Moderators, Administrators Posts: 32,008 admin
    Just to be clear--There are 2 grounds that we are talking about here.

    There is the safety ground (green wire or bare wire) that connects to the metal frame of each panel. All panel frames must be grounded via the green/bare wire.

    And there are the + and - wires that carry the electrical power from the solar panel to the charge controller, and then to the battery bank.

    Those wires are connected (it sounds like for you)--Two panels in series to the combiner box (- bus bar in combiner box to - panel A. + panel A to - panel B. + panel B to + breaker/fuse in combiner box).

    The only time you connect the - Battery Bus is at the - Battery (or - Battery Bus) to the ground rod at the main building. No where else. (it can get a bit more complicated if you have a DC Ground Fault Interrupter breaker assembly--Depends on your installation and code requirements).

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jonrjonr Solar Expert Posts: 1,386 ✭✭✭✭
    I don't know much about it, but burying a bare #6 ground wire (no conduit) from the ground rod at the panels to the house ground rod makes sense to me.

    I am available for custom hardware/firmware development

  • LumisolLumisol Registered Users Posts: 374 ✭✭✭
    A bare wire in the ground will quickly begin to erode quickly. You might want to use a much heavier wire for direct burial, 4, 2, 0, etc.
  • jonrjonr Solar Expert Posts: 1,386 ✭✭✭✭
    Even fairly thin copper pipes hold up well underground.

    I am available for custom hardware/firmware development

  • LumisolLumisol Registered Users Posts: 374 ✭✭✭
    Maybe use a copper pipe then. :)
  • solarhungrysolarhungry Registered Users Posts: 29 ✭✭
    Thanks for the replies. I'm not sure if I worded my post right but I plan on using bare ground  wire to all my panels. The instruction manual from my combiner box is showing to ground each string . 8 panels in series of 24 v will be 4 strings going to the combiner.
    And if this is correct ,then a bare ground wire going out of the ground bus bar from the combiner to the ground rod next to the array.
    Then a green ground wire from the ground bus combiner is going to the house equipment ground rod to tie it together.
    The positive,negative,and green ground will all be in a conduit buried to depth code. 
  • solarhungrysolarhungry Registered Users Posts: 29 ✭✭
    OK after reading more and  going through more pages in search, using key word combiner box. It looks like the answer is yes to running the ground wire back to the house , tie it in with the new  equipment ground rod.
    I'm seeing some using bare ground wire  running outside of the conduit  of the positive and negative cables going to the house which is supposed to absorb a lightning strike more with the soil. Do you recommend to do it this way or put the ground wire going to the house in with the positive and negative cables inside the conduit? And if inside conduit way can I use bare wire or does it have to be plastic coated example green ground wire? Thanks.
  • LumisolLumisol Registered Users Posts: 374 ✭✭✭
    It won't absorb or dissipate a strike, but it will help to dissipate the buildup of charge from the ions around the panels getting built up.
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