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WOW, explain this Too Close to a Very High Voltage Power Line? Did I Get Shocked?

  1. Sep 20, 2005 #1
    :surprised:

    Let me explain what happened.

    There is a great scenic overlook on top of the Appalachian Trail near my house. The overlook is mainly there because a power line travels up the mountain, and that section of the hill is clear cut to keep the trees out of the lines. The view is incredible!

    Midway between two transmission towers is a pile of large boulders which you need to climb to get the best view. This boulder pile (boulders about the size of a small car), puts you within 40-45 feet of the transmission lines. The height of the tower is about 100' from the ground, but this outcropping puts you closer to the wires since its at the midpoint of the two towers and is about 60' above ground level. I do not know the voltage of the lines, but you can hear crackling noises from the wires.

    My girlfriend was sitting on one of the boulders and I was standing up with thick rubber soled hiking boots on. The weather was clear, 84F, and humidity levels about 25%. We had not touched each other the few minutes we were on the boulder, and I didn't touch the ground since I arrived on that boulder.

    Then, I touched her hair with my bare hand, and immediately felt a buzzing/painful sensation in my hand! She felt it as well and became alarmed. At first I thought a bee or hornet was in her hair trying to sting the two of us. I grabbed my hat off my head and started to chase this insect away from her hair. NOTE: I didn't see an insect, but assumed it was because of the noise (a constant buzzzzzzzzzzzzzt sound and pain like a sting). I didn't feel or hear any buzzing while I was swatting at this "insect" with my hat.

    I looked down at my right hand, where I had touched her hair, and noticed a small red mark about 2mm in diameter. It looked exactly like bee sting, but there wasn't a stinger. I then went to touch her back and lift her hair to look for any sting marks and IMMEDIATELY the buzzing/pain sensation happened AGAIN!

    I could CLEARLY see that my hand was contacting her polyester/nylon shirt, and that there WASN'T and insect there, it was just my hand touching her back! I COULD SEE NOTHING TO EXPLAIN THE SENSATION OR NOISE, yet felt and heard something! I pulled my hand away from her after about 2s, and we both realized that the pain/noise we where both feeling must have been coming from some type of charge induced by the power lines! We both crouched low, didn't touch each other, and briskly made our way to another boulder which was not directly under this power line.

    I was about 40-45' away from the overhead lines when I was standing. It is hard to judge exactly how far overhead the wire was because the only thing behind the wire is the sky. This makes giving an accurate distance difficult, but I feel my estimate is correct. These wires are very thick, about 4" in diameter. They also crackle/hum constantly.

    What I feel happened is that some kind of static electrical charge built up in me, because I was standing, and was insulated with my rubber boots. Since my girlfriend was sitting, she was grounded, even though she was wearing boots. After thinking about it, the whole situation felt like one big, constant static shock, like the ones you get in the winter. Your typical static shock only last a few milliseconds in the winter after walking over a thickly carpeted area and touching a grounded object. Since I was so close to the wires (40-45') there was a "constant" supply of these free electrons and thats why we both felt that buzzing/stinging sensation for as long as we did.

    Am I way off base here, what do you think happened?

    Thanks!
     
    Last edited: Sep 20, 2005
  2. jcsd
  3. Sep 20, 2005 #2
    :surprised:

    Let me explain what happened.

    There is a great scenic overlook on top of the Appalachian Trail near my house. The overlook is mainly there because a power line travels up the mountain, and that section of the hill is clear cut to keep the trees out of the lines. The view is incredible!

    Midway between two transmission towers is a pile of large boulders which you need to climb to get the best view. This boulder pile (boulders about the size of a small car), puts you within 40-45 feet of the transmission lines. The height of the tower is about 100' from the ground, but this outcropping puts you closer to the wires since its at the midpoint of the two towers and is about 60' above ground level. I do not know the voltage of the lines, but you can hear crackling noises from the wires.

    My girlfriend was sitting on one of the boulders and I was standing up with thick rubber soled hiking boots on. The weather was clear, 84F, and humidity levels about 25%. We had not touched each other the few minutes we were on the boulder, and I didn't touch the ground since I arrived on that boulder.

    Then, I touched her hair with my bare hand, and immediately felt a buzzing/painful sensation in my hand! She felt it as well and became alarmed. At first I thought a bee or hornet was in her hair trying to sting the two of us. I grabbed my hat off my head and started to chase this insect away from her hair. NOTE: I didn't see an insect, but assumed it was because of the noise (a constant buzzzzzzzzzzzzzt sound and pain like a sting). I didn't feel or hear any buzzing while I was swatting at this "insect" with my hat.

    I looked down at my right hand, where I had touched her hair, and noticed a small red mark about 2mm in diameter. It looked exactly like bee sting, but there wasn't a stinger. I then went to touch her back and lift her hair to look for any sting marks and IMMEDIATELY the buzzing/pain sensation happened AGAIN!

    I could CLEARLY see that my hand was contacting her polyester/nylon shirt, and that there WASN'T and insect there, it was just my hand touching her back! I COULD SEE NOTHING TO EXPLAIN THE SENSATION OR NOISE, yet felt and heard something! I pulled my hand away from her after about 2s, and we both realized that the pain/noise we where both feeling must have been coming from some type of charge induced by the power lines! We both crouched low, didn't touch each other, and briskly made our way to another boulder which was not directly under this power line.

    I was about 40-45' away from the overhead lines when I was standing. It is hard to judge exactly how far overhead the wire was because the only thing behind the wire is the sky. This makes giving an accurate distance difficult, but I feel my estimate is correct. These wires are very thick, about 4" in diameter. They also crackle/hum constantly.

    What I feel happened is that some kind of static electrical charge built up in me, because I was standing, and was insulated with my rubber boots. Since my girlfriend was sitting, she was grounded, even though she was wearing boots. After thinking about it, the whole situation felt like one big, constant static shock, like the ones you get in the winter. Your typical static shock only last a few milliseconds in the winter after walking over a thickly carpeted area and touching a grounded object. Since I was so close to the wires (40-45') there was a "constant" supply of these free electrons and thats why we both felt that buzzing/stinging sensation for as long as we did.

    Am I way off base here, what do you think happened?

    Thanks!
     
    Last edited: Sep 20, 2005
  4. Sep 20, 2005 #3
    Well... maybe you shouldnt be hanging around large electrical tranmission towers.

    Its probably due to electric field created outside a wire. Similar to how if a large voltage is passed through a small rubber insulated wire you can still be shocked. The voltage in these sorts of towers is incredibally high to reduce powerloss.

    My best advice is dont hang around electrical tranmission lines. They spell bad trouble
     
  5. Sep 20, 2005 #4
    Spastik,

    This area is on a very well traveled hiking trail, and many people visit the exact spot we were at. I wouldn't climb a transmission tower, but this seems very safe. This boulder field was here long before the power lines were, and there are strict codes the electric co. needs to follow. This is why I found the whole experience "shocking" because it appears very safe. I have a picture. I will try to post if I can.

    Thanks

    PS I changed my estimate from the wire to about 45'. It really is hard to gauge this distance though.
     
  6. Sep 20, 2005 #5
    Those lines are packing alot of power. Given that , the proximity of you to the lines when up on the boulder and the low relative humidity I think you were getting shocked.

    Is the trail there because the cleared path for the power lines makes it easier to hike that area? I know the electric company has strict codes to follow but these aren't like the lines going up the street. I don't think the power company expects people to get as close as you did to the lines, if you were as close as you estimate that's practically the equivelant of climbing the towers. :eek:

    Someone correct me if I'm way off base on this next point but isn't that land the property of the power company or some kind of right of way for them with the towns :confused: Don't railroads and oil/gas companies have arrangements like that also :confused: If so then in the strictest sense you're not supposed to be there but it's like a tacit agreement between the public that the power company/town can't afford to restrict and monitor that land constantly (also I think there would be a big public outcry) but they don't expect the general public to get to close to the wires given the known dangers :confused:

    I don't know I'm just wondering because I've hiked those types of areas myself.
     
  7. Sep 20, 2005 #6

    Ivan Seeking

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    I have seen overhead power lines induce about 160 volts on the frame of a large vehicle that was parked underneath. This was not due to a "static charge", rather it happened due to an induced EMF [electromotive force] - the same principle on which transformers work. I don't see how this could happen to a significant degree as you described with a human body, but it sure sounds like the same effect.

    Edit: I should have said that I measured 140-160 volts using a high impedance meter. but the frame was grounded, and I did feel a significant shock when I touched the bus. This also caused the CAT Scanner inside to fail. We moved the bus and the scanner worked properly again.
     
    Last edited: Sep 20, 2005
  8. Sep 20, 2005 #7

    DaveC426913

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    Repeat the experiment. Take notes. Maybe bring instruments.
     
  9. Sep 20, 2005 #8

    matthyaouw

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    In these circumstances (and voltages), I'm not sure that it's the best idea...
     
  10. Sep 20, 2005 #9
  11. Sep 20, 2005 #10
    This brings up an important point: overhead power lines are not shielded, they are insulated. There is a difference.
    A high-voltage insulated powerline does not prevent the surrounding air from being ionized. To do that, one would need shielding, which would be far too expensive.

    In any event, the surrounding ionized air can most certainly ground itself through the proximity of a human body under certain conditions. Apparently, you met those conditions.
     
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