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electric shocks from car

Discussion in 'Automotive Electronics' started by Marcohilux, Jan 10, 2017.

  1. Marcohilux

    Marcohilux New Member

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    Hey guys, first of all sorry for my broken English, it's not my first language. I am camping at the moment with my pickup and a rooftop tent and just realised that every time I touch the car or any metal parts I get shocked. A multimeter between car and earth shows 90-120 volts ac. All my accessories in the car like Solar Panel and fridge work under 12 Volt Dc, no inverters or anything. Is it possible that this I caused by my rooftop tent and its annexe (usual tent material) which is hanging down on one side and maybe rubbing on the car causing electrostatic shocks? When u touch any metal parts of the car with the upside of your hand you can feel the metal slightly vibrating, as soon as I connect a wire from and earded pole to the chassis that vibration stops, and when I take the wire away the vibration comes back straight away and you might get shocked as well. Any ideas what it could be? As i said i only work 12 Volt Accessoires on it, no connection to any power plug
     
  2. JimB

    JimB Super Moderator Most Helpful Member

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    Is you car parked near or under an overhead power line?

    JimB
     
  3. Marcohilux

    Marcohilux New Member

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    Hey jim, thanks for quick reply :) its not parked close to a powerline, if it was is it possible that the power transfers down via the rooftoptent? Or from down bottom via wet tires?
    Kind regards
     
  4. dave

    Dave New Member

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  5. spec

    spec Well-Known Member Most Helpful Member

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    Hi MH,

    firstly your English and composition are very good. You explained very clearly what is going on.

    What you describe is odd and worrying.

    Can you disconnect the battery from your truck and see if the 120V AC voltage stops.

    By the way static electricity would be DC not AC and would be in the kilovolt range and also it would immediately discharge after giving you a shock.

    I am concerned that the voltage you are experiencing may be due to a fault in some underground power cables.

    If the voltage disappears when you move the truck to a different area, I would advise vacating the present position and informing the local electricity company.

    spec
     
  6. JimB

    JimB Super Moderator Most Helpful Member

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    On a couple of occasions, I have noticed this effect when my car is parked under high voltage power lines (quite safely, no danger of contact).

    There is a very small amount of capacitance between the car and the power line, and the car is now at some voltage above ground, due to the electric field between the power line and the ground,
    When you touch the car, a very small current flows through you to ground.

    If your car is not near any power lines, I do not see why you are seeing AC volts.

    Intriguing.

    JimB
     
  7. JimB

    JimB Super Moderator Most Helpful Member

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  8. spec

    spec Well-Known Member Most Helpful Member

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    As you say, intriguing.

    spec
     
  9. spec

    spec Well-Known Member Most Helpful Member

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  10. JimB

    JimB Super Moderator Most Helpful Member

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  11. Marcohilux

    Marcohilux New Member

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    Guys thank you very much for all your answers! When I texted back yesterday I wasn't at the campsite and pretty sure there are no powerlines around. But when I came back in the evening I realised there actually are big ones hanging low :facepalm: my car is still earded but do you think it's bad for all car electronic when that ac current is flowing through for the next couple of days?
    Marco
     

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  12. spec

    spec Well-Known Member Most Helpful Member

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    Your truck and you may be safe, but don't mess about: get out of there as soon as possible- sorry.

    spec
     
  13. spec

    spec Well-Known Member Most Helpful Member

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    Nice one Jim.:cool:

    spec
     
  14. JimB

    JimB Super Moderator Most Helpful Member

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    Yes, that will do it!

    The car will be OK, do not worry.

    "Earded". The English word is "Earthed".

    My own personal opinion is that although the official advice is that it is not known to be harmful, I would not hang around in an electric field of around 27kV/m (275kV on the line which is 10m above ground).
    Just moving the car a few metres away from being directly under the line will make a big difference.

    For some reason, high voltages like that make me feel uneasy. I don't know why, they just do. Whether it is psychological or there is a real effect I do not know. But I don't like being directly under high voltage overhead power lines.

    JimB
     
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  15. spec

    spec Well-Known Member Most Helpful Member

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    That is exactly how I feel too.

    The long term effect of that sort of exposure is not really known and anyway why take the risk.

    spec
     
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