lightening precautions for house-mounted panel

Greetings,

My starting point for solar, with an eye to learning how to size panels, batteries, charge controllers, etc, has been a water feature with a small pv panel.  The next step in my plan is to add a larger panel and scale upwardly from there for 24 hour operation.

My first lesson has been this: protect the assembly.  The cable from the panel has been recently vandalised and I want to mount it on the gutter of my asphalt roof to keep it out of harm's way.  I have cobbled an alum frame onto my metal gutter, with the wiring to the fountain hidden in the downspout and running on the ground under my deck.

Do I now run the risk of a damaging lightening strike to my house and equipment?  If so, what is the best means of mitigation?

Regards,
the gardener

Comments

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: lightening precautions for house-mounted panel

    there isn't any more of a risk than just what your gutters had presented. were your gutters grounded? of course not so at this point it isn't a problem, but if it bothers you you could run a ground wire from it all to a ground rod as it certainly wouldn't hurt.
  • System2
    System2 Posts: 6,290 admin
    Re: lightening precautions for house-mounted panel

    Thanks, Niel.

    At what point would you (or the engineering community at large) recommend that lightning precautions be taken?

    Is there an array size, arrangement, or complexity where prudence would require some measures to be taken? 

    I have plans for a larger array attached to my chimney, which is the highest and most metallic part of my home. That array will likely provide household backup power via a battery bank and inverter rather than "hobby" scaled yard and garden system I have now.


    Regards,
    the gardener.

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: lightening precautions for house-mounted panel

    technically anything metal up high presents a high potential for a lightning strike. i was assuming the water thingy was outside and not indoors as well. if indoors run a ground wire from the pv to a ground rod. i have discussed grounding in other threads and it would be a good idea to look them up and read them. what i said is still basically true of your downspouts, but most people don't ground their downspouts as they are outside only and fall near to the ground if not actually into the ground.
  • System2
    System2 Posts: 6,290 admin
    Re: lightening precautions for house-mounted panel
    gardener wrote:
    I have plans for a larger array attached to my chimney


    Just wondering, have you thought out the stresses this will have on your chimney, especially in heavy wind?
    And, I hope you don't burn wood or coal.
    Cheers
    Wayne
  • System2
    System2 Posts: 6,290 admin
    Re: lightening precautions for house-mounted panel

    For now, I just want to keep my small system up out of the way of vandals, and the fountain flowing for a longer by charging some NiMH. This, of course, without burning my home down in the mean while.

    The more grandiose scheme is/was to feed my home's parasitic current by using some serious panels in a more optimal location.

    I had not given wind load a serious thought, my thanks to Wayne. The chimney visible from the street is more of a sheet decorative metal shell fastened to the roof. The natural gas flue passes up through it from my water heater. When I go electric-on-demand with the hot water, the whole thing becomes purely decorative. It seemed like a good way to feed the cables from the panel array to the proposed battery bank.

    A good north west blow might just send the panels sailing down the street without some additional reinforcement.

    The downspout I have in mind for the small project dumps into a plastic rain barrel. I will keep an eye on the other threads before I get carried away.

    Regards,
    the gardener