Is Grounding necessary on my small off grid system?

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • mattc
    Junior Member
    • Jan 2013
    • 28

    #1

    Is Grounding necessary on my small off grid system?

    I have a small off-grid system comprising of 3x 60W 12v panels, PWM Controller and 2x 50Ah Batteries running in parrallel. Panels are on top of the shed roof using thick aluminium bolted brackets. Shed is on a constructed solid plastic base (those tough plastic square peices that connect together) which is on top of garden concrete slabs.

    So as it stands (literally).. almost every material underneeth the panels is a really bad conductor of electricity. I live on the edge of town in a housing estate. There's a school sports field with 6 flood light towers standing high (about 100 - 150 meters from the house so not super close).

    Given all these fcators, is it recommended to ground the panels or would this just increase the chances of a strike?

    Cheers
  • mschulz
    Solar Fanatic
    • Jan 2014
    • 175

    #2
    Watch this video, it really helped me with this question.

    Comment

    • billvon
      Solar Fanatic
      • Mar 2012
      • 803

      #3
      Originally posted by mattc
      Given all these fcators, is it recommended to ground the panels or would this just increase the chances of a strike?
      If your shed gets struck by lightning (and it can always happen) the current WILL flow to ground. It can go via an explicit path (i.e. a grounding conductor) or via your DC wiring/inverter/batteries.

      If lighting strikes nearby the coupled electrical field will induce large transients in your frames which will again couple to ground one way or another.

      If you can live with losing the system/shed, and you are not putting anyone at risk, then the need for grounding goes way down.

      Comment

      • Shockah
        Solar Fanatic
        • Nov 2013
        • 569

        #4
        Originally posted by mattc
        Given all these fcators, is it recommended to ground the panels or would this just increase the chances of a strike?

        Cheers
        A question I have never found a black and white answer to... sort of falls in the same category as religion, nutrition & politics.

        From what I've been told,
        a proven drawback of grounding a low voltage off-grid system would be reversed-lighting-charge flowing from the ground-rod into the battery/cc/pv... ?

        IIRC, for systems less than 48v, it is better to "float" them (not grounded)... with fuses on both + & - battery terminals... ?


        DISCLAIMER: Question marks inserted to discourage statements from being interpreted as advice.

        If you are unsure about grounding your Off-Grid system, seek written advice from a local licensed/insured electrical contractor.
        [CENTER]SunLight @ Night[/CENTER]

        Comment

        • Mike90250
          Moderator
          • May 2009
          • 16020

          #5
          I think most electrical codes want a ground in the system. Even straight DC systems. Even if it looks like the grounding increases the likelihood of a strike !

          If you have an inverter, then the grounding changes, according to the manual for the inverter.

          Even small generators have a ground terminal to be connected to a ground rod.
          Powerfab top of pole PV mount (2) | 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

          Comment

          Working...