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Medical Electric shock

  1. Jun 5, 2010 #1
    Q: Does a human being is forced away from the wire when he touched the wire and got an electric shock?

    what is the voltage and force of the shock that applies a force on the person to jump away from the touched wire.
     
  2. jcsd
  3. Jun 6, 2010 #2

    tiny-tim

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    Hi smslca! :smile:

    I believe the force that moves the human is the human's own muscle force (and not electromagnetic) …

    I believe it's simply caused by violent contraction of the muscles.

    So, if you risk touching a cable that you think might be live (and you can't isolate yourself from earth), present the back of your hand, not the front, so that the contraction will pull your hand away from the cable, rather than make your hand grasp it.
     
  4. Jun 6, 2010 #3
    I understood ur answer.

    But I want what is the numerical value of force and voltage, that causes a man jump away from the cable, like a ball moving away from the bat when it is just struke by the same bat.

    Is there any voltage that can move (I know it is a small distance compared to ball hit by bat) a human being like the ball by the current in the wire giving a jolt.
     
    Last edited: Jun 6, 2010
  5. Jun 6, 2010 #4
    i don't think you will find a good answer to that. to the best of my knowledge, actual electrocution experiments were done on animals like dogs. and with an actual person being shocked, the result will depend a lot on the path of the current, the surface area of skin exposed to the electrical conductor, the conductivity of the skin (salt, perspiration, subcutaneous fat, etc), the applied voltage, the applied frequency, etc.

    i'm not quite sure i understand the second question, but one thing that will often happen in a high voltage electrocution is that enough current passes through the body to boil the blood, causing an explosion from the rapid vaporization of the water.

    otherwise, you could treat the body as just another current conductor and compute the force between the two conductors the same way you would between two "wires".

    http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/wirfor.html
     
  6. Jun 11, 2010 #5
    Proton,

    To add a little meat to the stew.

    (1) About 10 milliAmps passing through a muscle will cause involuntary contractions. If that current passed through a hand which is grasping a hot cable, then the digital flexors and extensors will contract at the same time, with the flexors winning and causing the hand to grasp tighter.

    (2) GFCI recepticals are set to trip at aprox. 5 mA leakage from the system, thus protecting humans from extended shocks. The initial leakage can feel like a good shock, but it is nothing like an extended shock which can be deadly.

    (3) Electrical shocks applied to a sweaty body "MAY" pass through more sweat than body, and (as I have witnessed) thus may cause less damage. The 'knee jerk' reaction from a body under sweat carried shock may cause one to be propelled away (or toward) the source of the electrical shock. There is no safety in the sweat effect, it is just one overlooked means by which electrical energy passes through and around and over a human body.

    (4) The level of Voltage is not the only issue; and given that there is a wide range of resistance within the human body, we must deal with the effects of widely varying currents which can be forced through the many parts of the human body. Given that there are many paths that electrical current can be forced to take, the whole subject gets both complicated and (to me) gruesome. I have seen sweat burns, 3rd degree burns, and death as the result of electrical shocks.

    As you said, Proton, "I don't think you will find a good answer to that." !

    Since I don't frequent this forum, I probably will not see your continued responses to this interesting topic. You may critique my offerings as you see fit. You seem to be rational and I wish you good communication with the others.
     
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