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Thread: Electrical Question

  1. #51
    Join Date
    Jan 2014
    Location
    Western North Carolina, USA
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    1,169

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    At my $dayjob it is part of my job description to get obsessive about grounding.... so maybe I do take it to a fault, but it's a big part of what I do day to day for my living.

    I have the equipment to perform ground resistance tests here, a nice little clamp-on meter, and our ground here, in heavy mica soil, is 0.25 ohms, thanks to the multiple 20-feet long copperweld rods, chemically enhanced, in an alternating signal/safety ground grid, with three electrode fields, bonded with multiple 500kcmil copper grounding electrode conductors exothermically welded to a 2x16 inch by 15 feet long solid copper 'single point' bond (home runs of 500kcmil each individually welded) with two 500kcmil copper conductors tying the three electrode fields together and to the buildings on site (they're buried quite deep, and the single-point bond is under a really large concrete pad, so it's relatively safe from copper thieves....plus we have security.).

    There are over 100 rods in our ground electrode system here. But, with two 26-meter 300+ ton x-over-y parabolic dish antenna structures rising from the valley floor we kindof need it.

    Well casings sound like a good idea until you get fault current from a lightning strike that takes out your pump.

    The most effective thing you can do is extend the electrode field along one or more radials that will drain the current away from the structure, and use the heaviest gauge grounding electrode conductor you possibly can. And ALWAYS ALWAYS ALWAYS make sure all ground electrodes with conductors coming into the house are bonded OUTSIDE the house prior to entering. I've seen the results of a lightning strike on two separate electrode fields that weren't bonded properly, and the results are not pretty.
    --
    Bughlt: Sckmud
    Shut her down Scotty, she's sucking mud again!

  2. #52
    Join Date
    Jan 2007
    Location
    Pacific Northwest, USA
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    The good news is that a thunderstorm in these parts is a very rare occurrence. I think that the only lightning strike in the area hit the top of a butte about 25 years ago and started a small brush fire. Sometimes we'll hear a bit of thunder in the coastal range mountains or in the Cascades--but almost nothing locally.

  3. #53
    Join Date
    Apr 2010
    Location
    Albany, OR USA
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    Quote Originally Posted by Chuck(G) View Post
    The good news is that a thunderstorm in these parts is a very rare occurrence. ....
    I was camping at Alsea Falls a few years ago and experienced a terrifying electrical storm that lasted most of the night. It seemed to be traveling in a circle, coming over and over again. I figure you, being only about 40 miles from there, would have been in it's path as well. Maybe the lightning activity got more intense where I was. I guess I'm having trouble believing that lightning is that rare in your neck of the woods when I've witnessed some dramatic lightning in the mid and southern Willamette valley.

  4. #54
    Join Date
    Jan 2007
    Location
    Pacific Northwest, USA
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    I've been here 30 years and only have seen the occasional thunderstorm--and nothing remotely resembling the stuff I'd see in the in the midwest. And I'm above 1000'. Honestly, I'm more afraid of freezing rain.

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