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If a transmission line falls on your car, is it safe to touch metal inside the car?

  1. Jul 28, 2012 #1
    I mean even something tiny, like the seat-adjuster...would that electrocute you to death?

    Is it possible to touch something plastic and still get electrocuted?
     
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  3. Jul 28, 2012 #2

    phinds

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    Re: If a transmission line falls on your car, is it safe to touch metal inside the ca

    Given the very high voltage in transmission lines, and their ability to move a LOT of electrons (current), I'd guess that the fact that MOST of the electricity should flow through the outer shell of the car to the ground would NOT stop their being enough stray current to spark through your body from, say, your hand on the gearshift and your arm next to the door, so yeah I'd say you could get fried, although not like what you would if it was just you the transmission line hit.

    I'll be interested to see if other have a more knowledgeable take on the question.
     
  4. Jul 28, 2012 #3
    Re: If a transmission line falls on your car, is it safe to touch metal inside the ca

    would touching plastic be dangerous too?
     
  5. Jul 28, 2012 #4

    PhanthomJay

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    Re: If a transmission line falls on your car, is it safe to touch metal inside the ca

    First and foremost, stay inside the car. Stepping out could be fatal. If you are forced to get out, and i do mean forced, due to say fire, you've got to jump out clear with both feet without touching the exterior of the car. Not easy. Touching plastic while within the car should be no problem . I'd stay away from touching metal especially if it is an electrical part of the car like a radio. In the extreme example of being forced to exit, you'd probably be ok opening the metal door handle , but this is the last resort.
     
  6. Jul 28, 2012 #5
    Re: If a transmission line falls on your car, is it safe to touch metal inside the ca

    The body of the car forms somewhat of a Faraday cage. But for that to be true, all metal parts must be electrically connected. If I were in that situation I would not bet my life on it. I would just sit tight until the power lines were turned off and removed. If I must exit then I would do as PhanthomJay described.

    You may find this video interesting:
     
    Last edited by a moderator: Sep 25, 2014
  7. Jul 28, 2012 #6
    Re: If a transmission line falls on your car, is it safe to touch metal inside the ca

    I do not KNOW what would happen, but touching anything unnecessary is NOT safe. There would be no way to tell for example if power was flowing thru tires to the ground or not.

    Also, I don't know the range of voltages in transmission lines....but touvhing stuff would NOT be a good way to find out!!

    Wiki says:
    http://en.wikipedia.org/wiki/Electric_power_transmission

    and I have read discussions about 345,000 volt transmission lines!!!

    Also, for comparison, about 10 to 15 thousand volts are necessary to jump a spark plug gap..[modern transistor ignitions gor much higher].....so transmission line voltages are certainly capable of jumping open space....especially if ANY ionizing is present....
     
  8. Jul 28, 2012 #7

    PhanthomJay

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    Re: If a transmission line falls on your car, is it safe to touch metal inside the ca

    A 100 kV line can jump about a 1 ft air gap to a grounded object or person. More like 3 or 4 feet at 300 kV. There have been instances where careless crane or dump truck operators have made contact (or come in proximity close enough to draw the arc ) with hi voltage lines. Generally speaking, those who remained inside the vehicle have survived; those who have tried to get out sometimes have not.
     
  9. Jul 28, 2012 #8

    Danger

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    Re: If a transmission line falls on your car, is it safe to touch metal inside the ca

    I really have to start wearing my glasses. Up until Turtlemeister's post, I thought that the OP asked about if a transmission line fails on a car. I figured that everyone was teasing him, because since when are transmissions electrically charged? :redface:
     
  10. Jul 28, 2012 #9
    Re: If a transmission line falls on your car, is it safe to touch metal inside the ca

    I've been taught in electrostatics lessons that ALL of the charge is on the outside of a 'faraday cage'....ALL of it, not most of it.
    If the car is metal and is connected to the ground I think that is a faraday cage. If it was me i would touch the inside for a bet and I would win.
    @Naty... I would hope that current was flowing through tires but is should not if the metal body is connected to the ground.
    I think people in aeroplanes do not get a shock when it is hit by lightning.
    Also....345,000V transmission lines do not occur 'in discussions'.....they are real....some are bigger than this.
     
  11. Jul 28, 2012 #10

    krd

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    Re: If a transmission line falls on your car, is it safe to touch metal inside the ca

    If the transmission line falls on your car, the car will become charged - the current will not flow to the ground because of the tyres.

    While you're in the car, you're safe to touch any of the metal etc - because there isn't a circuit between you and the ground. If you get out of the car, and while you're getting out if you touch the metal parts of the car (high enough voltage any part will do), a circuit may be made between you and the ground. And the electricity will flow through you. And you will be cooked.

    And I've heard....you will smell like a roast chicken.

    Lightening strikes are interesting, as it's a much higher voltage and more power - if you're struck by lightening, it will conduct over the warm air just about your skin, so very few people die from lightening strikes. If it went through you, you'd be burned to a cinder.
     
  12. Jul 28, 2012 #11

    Danger

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    Re: If a transmission line falls on your car, is it safe to touch metal inside the ca

    And in their case, the tires are of absolutely no use.
     
  13. Jul 28, 2012 #12
    Re: If a transmission line falls on your car, is it safe to touch metal inside the ca

    Tires no use !!!
    Full flaps....that's a tennis court!
    Don't get the logic, please explain
     
  14. Jul 28, 2012 #13

    PhanthomJay

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    Re: If a transmission line falls on your car, is it safe to touch metal inside the ca

    A car is not a perfect faraday cage. Half of them are made of cheap plastic. But neither a plastic body nor rubber tires may have the insulating properties to withstand 100 kV. I've seen photos of melted tires from powerline contacts.
    In a perfect faraday cage, you can touch the inside of the metal cage if standing within , and be just fine at any voltage. In a car, whether it is grounded or not, I would refrain from touching metal, even if it may not cause harm. Be safe!
    Regarding lightning , many have been killed , either by direct hit or more often, from the voltage gradient from a nearby strike to ground. That is why if stuck in the open during a lightning storm and shelter ( or a faraday cage ) is not nearby, you must crouch low and click heels together so that ground currents pass thru your feet and not your heart.
     
  15. Jul 28, 2012 #14

    krd

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    Re: If a transmission line falls on your car, is it safe to touch metal inside the ca

    Yes, but. If you're in a car and it's struck by lightening - the arc will just have a few inches to travel to the ground. So, it's pretty safe to be in a car in a lightening storm - but your ears might be ringing. It's interesting how lightening prefers the air over a solid conductor - i think it's the air becoming ionised.

    As for lightening striking in the same place twice - there's always a good chance it will. I didn't know the guy, but my father and lots of other people did. A farmer near where I grew up. He was watching a lightening storm out of his bedroom window (they're always fun to watch). He got struck. It burned all the hair off his body, but he was fine otherwise. So.....a period later there was another lightening storm.....and as he believed the old wives tale, so he went to his bedroom window to watch it - believing he was safe.......And of course he was struck again. ....It didn't kill him....but it was the last time he observed lightening storms from his bedroom window........It a site gets struck once, it may have geo/electrical properties that make it likely for a repeat strike.
     
  16. Jul 28, 2012 #15

    Danger

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    Re: If a transmission line falls on your car, is it safe to touch metal inside the ca

    The CN tower gets struck about 75 times per year. It's something like 25 times for the Empire State building. I don't know what the number is for the Eiffel tower, but I wouldn't want to be leaning against it in a storm.
    Emily, I was referring to what Phantom said. I've seen vehicles that were struck, and in several cases the tires exploded and melted. Even in cases where they remain intact, the lightning just jumps the gap between the pumpkin or rims and the ground.
    Incidentally, I saw it reported about 40 years ago that the single most common complaint of lightning victims was deafness. The thunder can knock your eardrums half-silly.
     
  17. Jul 28, 2012 #16

    PhanthomJay

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    interesting stat, thanks. S.O.P. In lightning storms when no options available is to crouch low to the ground on balls of feet with heels clicked together, AND block your ears!
     
  18. Jul 28, 2012 #17
    Re: If a transmission line falls on your car, is it safe to touch metal inside the ca

    Sounds like a lot of people are basically stating that you dont know exactly what the pot diff between diff. objects are in this type of situation so the flow of current can be rather random due to so many variables.

    The OP was given some basic strategies based on the most likely situation. Bottom line is you cant see these large pot differences until current flows. And the situation may change after current does flow, you may have a diff set of pot. differences between objects from one moment to the next. You dont wish to be the conductor that allows the pot diff to ground ya big bags of conducting saltwater.

    Even if roasted chicken smells good...

    And I've heard....you will smell like a roast chicken.
     
  19. Jul 28, 2012 #18

    Danger

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    Re: If a transmission line falls on your car, is it safe to touch metal inside the ca

    If you're on that much pot, you probably won't even notice that you've been electrocuted.
     
  20. Jul 28, 2012 #19
    Re: If a transmission line falls on your car, is it safe to touch metal inside the ca

    But you would smell good to others in the kitchen. So... its a trade off.
     
  21. Jul 28, 2012 #20

    Danger

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    Re: If a transmission line falls on your car, is it safe to touch metal inside the ca

    While I have nothing against a little friendly cannibalism, the idea of smelling good to my companions is a wee bit disconcerting...
     
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