Questions about Proper Grounding

Solarguy1
Solarguy1 Registered Users Posts: 9 ✭✭
in PV Installers Forum - NEC, Wiring, Installation #1
Hello all,
I have an off-grid system that I'm installing and have a question about grounding. I have read a lot about it, but I am still confused a bit.

I have panels that will be mounted on Tamarack rails that will be grounded to a grounding rod via #6 AWG solid copper. This is all outside of my structure.  My combiner box and inverter will be inside my structure as well as an AC panel.

My question is, how do I ground the inverter and AC panel? Do I tie all of my grounds to the #6 AWG copper? I've read that you only want to have 1 ground as to not have a ground loop. I've also read that you do not want to bring the #6 AWG copper ground from the panels inside the building because it is there for lightning strikes and if there ever was a strike, you don't want it coming inside. 

I "think" that I would need a separate grounding rod and ground wire for the inverter and AC panel. I'm imagining that if you had a bunch of panels that were a distance from your house, that your panels and inverter / AC panel would not share the same ground. Am I correct in thinking this?

Lastly, I have read that your batteries should be grounded as well off of the negative. Is this true as well?

My inverter is a Phocos PSW-H-3kW-120/24v  if that helps...

Thanks for any input!!!
Tagged:
· Share on Twitter

Comments

  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #2
    Are the panels mounted on your roof or a pole or ground mount ?

    If you use 2 ground rods, they must be tied together with heavy wire, ( #4 maybe?)
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

    · Share on Twitter
  • Solarguy1
    Solarguy1 Registered Users Posts: 9 ✭✭
    #3
    Mike,

    The panels are on the roof of a patio cover. 

    Is it acceptable to use 2 ground rods? 1 for the panels for possible lightning strikes and 1 for the inside equipment? 

    Thank you!


    · Share on Twitter
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #4
    Yes, but ground rods are required to be wired together with #6 or heavier wire, to avoid Ground Step Potential
     google it, there are some fun videos and illustrations about it


    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

    · Share on Twitter
  • Solarguy1
    Solarguy1 Registered Users Posts: 9 ✭✭
    #5
    Thanks Mike! I will for sure connect the 2 grounding rods with 6awg since that is what I have.

    Another thing I have learned here is that I should keep my combiner box OUTSIDE the structure in case of lightning strikes. 

    I almost have everything figured out!  :D
    · Share on Twitter

Categories