Grounding & Lightning Protection

MexDog
MexDog Solar Expert Posts: 28
I’ve just finished the installation of a second, larger system here in rural Mexico, not the system I had questions about previously. Lightening is a major concern here, and my questions concern proper grounding and surge protection.

The system is: 12 suntech 200w panels, Outback 80cc, Outback FX 3600w inverter.

I have put in place all of the lightening protection I can think of, such as a Tri-Metric 220 with the 48v lightening protection add-on, and Delta DC & AC lightening arrestors at the combiner box, cc, and AC load center.

The only bare copper I could find here is AWG#6 bare stranded (solid not available). I have run that from panels to combiner, combiner to DC load center grnd bus, and finally DC load center grnd bus, out to grounding stake. I have also bonded the cc, inverter, and negative battery post to this grounding electrode conductor (after the DC load center) using the same #6 bare stranded. Finally, I have added additional grounding electrode stakes forming a five foot circle after the first stake as I have seen illustrated in a few books and articles.

My questions are these:

Does this all sound OK?
Should the AC load center also be bonded to the grounding electrode conductor. It does have a ground lead in from the inverter already. My books show it both ways, with, and without a separate equipment ground lead bonding it back to the main grounding electrode conductor. Opinions on this???
Would there be any point in doubling up the #6 conductor run from the DC load out to the stake to "invite" a surge out to ground that way by creating a path of even less resistance?
Should the grounding electrode conductor from the panels go straight to the stake with all components bonded to it, rather than the route via the combiner and DC load center as described above?
Is there anything else I should be looking at doing such as anadditional air terminal lightening rod running off of the grounding stake?

As Always, thanks so much for your excellent help!

Dan

Comments

  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Grounding & Lightening Protection

    Grounding is one of those "arts". I don't have an answer, but is there any way you can sketch this up, 'cause I'm sort of lost trying to follow it all.
    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

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  • nsaspook
    nsaspook Solar Expert Posts: 396 ✭✭✭
    Re: Grounding & Lightening Protection

    The first thing is to keep the energy out of the house and directed in the ground via your ground rods or grounding system. A outside combiner box with a short straight strap (flat wide copper is best) to the grounding system is a good place the put the DC surge protector. Then have only one good ground connection point with everything star wired to it. If you have grid power a AC surge protector at the meter with its ground bonded your grounding system will help stop power line surges. In a near strike what you want to stop is GRP from sending current into the internal wiring if you have multiple grounding sources. In a direct strike all bets are off the table unless you have mil-spec grounding.

    Polyphaser links:
    http://www.polyphaser.com/techdocs/Ground%20Systems.pdf
    http://www.polyphaser.com/technical_notes.htm
  • bryanl
    bryanl Solar Expert Posts: 175 ✭✭✭✭✭
    Re: Grounding & Lightening Protection
    have only one good ground connection point with everything star wired to it.
    This is critical for the power components protection to avoid ground loop problems and keep the protections to be able to handle surges that occur within the system due to induction or leaks. It can be difficult if the system is dispersed, though.

    There needs to be a separate lightning protection system as well, I think. The primary part of this is lightning rods properly spaced to protect the power system components. See Structural Lightning Safety - National Lightning Safety Institute (NLSI).

    There's a lot of interesting stuff about this topic and the gist of it from what I can tell is that there is no magic bullet solution to eliminate risk of damage.
  • MexDog
    MexDog Solar Expert Posts: 28
    Re: Grounding & Lightening Protection

    Lot's of great material at that web site. Thanks!