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Does my lightning rod sound worrying to you?

  1. Jul 8, 2007 #1
    I have two lightning rods. One is at the highest point on my roof and has a pointed tip and is attached to a thick piece of copper that goes 8 feet into the ground. That one makes me feel safe.

    But the one attached to my solar array is horizontal in a 14 inch deep trench in the ground... right where the run off from the roof is.

    It worries me. What if someone were walking over that area during a lightning storm and lightning struck... wouldn't the water sizzle the person....?

    This may be a more theoretical forum, than applied.

    I just would really like to know. I've asked at several different forums and haven't gotten much in the way of definitive answers.

  2. jcsd
  3. Jul 8, 2007 #2


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    The only way you can get a definitive answer is to hire an expert in grounding systems to evaluate and test your particular system.

    The safety (or lack thereof) is primarily defined by soil conditions, which can vary with weather conditions.

    Most grounding systems are installed by rules that generally apply by building electrical codes
    In the worst case they may not work at all.
  4. Jul 9, 2007 #3

  5. Jul 9, 2007 #4
    I think I misunderstood your post in the other lightning rod thread - you're saying that the lightning rod itself is buried in the ground? I really doubt that. Lightning rods must be grounded, i.e. connected by a conductive cable to a bar or rod buried in the ground, but they themselves are mounted at a point higher than whatever they're protecting. It sounds as if the rod you're speaking of is not a lightning rod at all, but is the grounding rod for your solar array. This makes sense, since the array probably has electrically conductive materials in it, and thus could act as a lightning rod itself (albeit a poor one). You wouldn't want the array to be struck by lightning and have the current carried by your electrical system into your house. Roof antennas must be grounded for the same reason.

    In any case, I don't think anyone walking over the area where the rod is buried would be in any danger of having a lightning strike pass through him. Remember that you can touch a wire that is carrying a large current, and as long as you are not providing a better path to a point of lower potential (e.g. ground), you won't get any current flowing through you. What you might suffer is a burn on your finger, if the conductor has become hot, which they can do. The same is true for your friend - he won't be creating a "better" path for the lightning to get to ground, but he might be very near super-heated air or metal - that would be more likely to cause him harm. I've known people who were within a few meters from where lightning struck and they were thrown quite a distance by the blast of air.

    Better to stay safely inside when there's lightning overhead.

    - Bruce
  6. Jul 10, 2007 #5


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    While the majority of current will travel through the less resistant leg of the circuit, some amount of current will pass through the higher resistance leg - think parallel circuits.
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