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Electrifying Lamina Roof

  1. Jan 14, 2010 #1
    Ok I have an electric fence behind my house. And next to it is a small building that has a lamina roof. I would like to electrify this roof using the current from my fence. Does anyone know of a way to make this work right. From what I know there has to be a ground output for the electrification to work right, that's why the fence works, when you touch it your grounded. But if someone or an animal is on top of the roof it won't go off since there is no ground, right? Or am I thinking about this too much?

    Thanks for any advice you can give me.
  2. jcsd
  3. Jan 14, 2010 #2


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    Staff: Mentor

    You are correct. If you electrify the whole roof, there is no complete circiut when the animal is standing on the roof. Just like birds can sit on a high-voltage power wire and not notice anything.

    If you could electify alternating insulated metal strips on the roof with opposite phase (do fences use AC or DC?), then you might get reliable shocking between the hooves/feet of the animals.
  4. Jan 14, 2010 #3


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    Science Advisor

    That sounds like difficult legal stuff.

    Anyway, from a technical angle, it wouldn't help to electrify a roof except that someone might get zapped climbing onto it. Once he was on it, he would be like a bird on a power line. There is no voltage across him, so he doesn't feel anything.

    You could earth the roof and have bare wires running across it that are insulated from the roof.

    So, someone could touch the wires while grounded and get zapped.

    However it is not like a fence where he has a way of getting away. Someone could get trapped on a roof and continue to get shocks.

    What if he had a heart attack or fell off the roof?
    In my country, you can't set man-traps and if you did cause serious injury, you could be dragged into court because of it, even if the person was a burglar or worse.
  5. Jan 14, 2010 #4


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    Staff: Mentor

    Ah, I missed the part where he said "someone or an animal". My bad. Yeah, electrifying a confined space or a rooftop where a human could be would not be good.
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