do a person undergo electric shock in this situation????

Discussion in 'General Electronics Chat' started by going_in_deep, Aug 19, 2009.

  1. going_in_deep

    Thread Starter Member

    Jul 25, 2009
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    i read in this book that " IT IS CURRENT WHICH KILLS THE PERSON, NOT THE VOLTAGE" AND THE PRINCIPLE IS "PERSON DOES NOT UNDERGO SHOCK IF HE TOUCHES ELECTRICALLY COMMON POINT "
    if a person touches a live conductor of very high voltage and current he doesnot undergoe any electric shock as shown in the figure (00058) because there is not path for the current to flow. so here i got a doubt just take a look in the 2nd attachment (00059) here is my question
    1. will the person undergo shock in this situation(yes or no) ????
    2. please support your answer..

    well i guess, that person will undergo electric shock because if not all, at least some amount of current would flow through that body which causes voltage drop across the body. is my guess wrong?? IS THAT PRINCIPLE TRUE ???
     
  2. ELECTRONERD

    Senior Member

    May 26, 2009
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    In your first circuit, you already have a resistor completing the circuit. Thus, you will not get shocked where you are because the electrons will take the shortest path to ground. Same for your second circuit, you won't get shocked because your simply touching the negative wire but if you touched the positive wire and negative wire close to the battery you would get a zap. Or, if you touched the positive wire and touched ground you would get shocked. Of course, that depends if the voltage is high enough to overcome your body resistance which I'm sure it will be.
     
  3. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
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    However....as the saying goes..."Don't try this at home"
     
  4. ELECTRONERD

    Senior Member

    May 26, 2009
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    Right! :D He'll have to take our word for it.
     
  5. going_in_deep

    Thread Starter Member

    Jul 25, 2009
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    thanks kl7aj for u r kind advise
     
  6. going_in_deep

    Thread Starter Member

    Jul 25, 2009
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    now MR. ELECTRONERD????
     
  7. going_in_deep

    Thread Starter Member

    Jul 25, 2009
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    suppose a person hanging by touching both the hands only to the positive wire without touching anything other than just hanging in the air of very very high voltage... forming parallel circuit to the wire , now would the person get disaster shock??? or not???
     
    Last edited: Aug 19, 2009
  8. ELECTRONERD

    Senior Member

    May 26, 2009
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    Yep that will give you a shock for sure.
     
  9. ELECTRONERD

    Senior Member

    May 26, 2009
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    If a person was hanging onto the positive wire in midair he wouldn't get a shock. That is if he is far enough away from ground. If the electrical potential is really high and he is a few inches from the ground, an electrical arc can go to ground.
     
  10. davebee

    Well-Known Member

    Oct 22, 2008
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    Current kills, not voltage - that's like saying "Don't be afraid of falling off a tall building because its not the fall that kills person, it's hitting the ground".

    In real life, it is voltage that causes the current to flow which then kills a person, so voltage deserves a little more respect than this book would suggest.

    In your first circuit, the guy may be shocked. Current divides according to the ratio of resistances; a higher resistance will allow less current to flow but there still be some current flow. So depending on how high the voltage is, how large the resistance is and how resistive the person is, he could receive a fatal shock.

    On touching a high voltage, you still will get an initial burst of current flow into your body as your body capacitance charges. I don't know if that has ever been shown to be enough to be harmful, but my point is that your book is being overly simplistic on something that can kill you.
     
  11. rspuzio

    Active Member

    Jan 19, 2009
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    This is why Tesla, in addition to suggesting that people think
    clearly, also suggested only using one hand and keeping the
    other safely tucked away in a pocket or behind the back when
    working with live high voltage circuits.
     
  12. beenthere

    Retired Moderator

    Apr 20, 2004
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  13. going_in_deep

    Thread Starter Member

    Jul 25, 2009
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    hi dave thanks for your answer.. anyway this is nice from you "its not the fall that kills the person its hitting the ground "
    thank u ...
     
  14. going_in_deep

    Thread Starter Member

    Jul 25, 2009
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    ok compared to human being resistance a bird resistance is quit less. ... which lets the current to flow easily than humans.. but still i see many birds resting on the high electric wires in front of my home this is what iam confused of.. please help me out with correct answer....
     
  15. ELECTRONERD

    Senior Member

    May 26, 2009
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    Well the birds that are resting on your electrical wires don't undergo shock because they aren't touching ground. So a negligible amount of current is flowing through them that is harmless.
     
  16. davebee

    Well-Known Member

    Oct 22, 2008
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    There was another thread on this topic where someone said that on high voltage transmission lines that get up into the hundreds of kilovolts, birds start to develop corona discharge from their feathers, which they find uncomfortable, so they don't sit on these lines for long!
     
  17. ELECTRONERD

    Senior Member

    May 26, 2009
    1,146
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    Yeah, that's when the voltage potential gets really high! :p But I'm in the USA so de' birds don't worry about that.
     
  18. Audioguru

    New Member

    Dec 20, 2007
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    If the high voltage is AC then you will be continuously zapped.
     
  19. going_in_deep

    Thread Starter Member

    Jul 25, 2009
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    0
    well the birds which rest on the live wires in front of my house is of very high voltage ac (220v @ 6 amps @ 50hz) but still the enjoy sitting on them. compared to human being resistance a bird resistance is quit less. ... which lets the current to flow easily than humans.. but still i see many birds resting on the high electric wires in front of my home this is what iam confused of.. please help me out with correct explanation...
    and here is one more attachment image, if suppose i touched a high voltage AC(220v , 6 amps @ 50hz) with only my two fingers and rest of my body is touching no where i mean iam just hanging up in the air as shown in the figure ,now the total resistance of my body is reduced to large extent through which the current flows from point A to the point B (i.e entering into my 1st finger to the exiting from my second finger)
    DO I EXPERIENCE SHOCK NOW....??????????
     
  20. b.shahvir

    Active Member

    Jan 6, 2009
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    0
    Now, my 2 cent worth; ;)

    Both the circuits will prove fatal if it operates on HV i.e. in the range of say, 110KV or more. This is due to the fact that inspite of the person being in contact with only one conductor, in either case, the leakage and capacitive (in case of AC system) currents w.r.t. earth are considerable in case of High Voltage (HV) and Extra High Voltage (EHV) lines to zap one's life out. the high leakage and capacitive curents are due to large electric fields and potential gradients in air surrounding the conductors. The air undergoes rapid ionization and as a result becomes somewhat conductive. Hence this is a purely theoretical case not to be tried out in practice on HV systems.

    For voltage drop across fingers in case of 220V supply, sensation of shock is practically negligible, although micro-amps would flow thru the fingers.

    Kind regards,
    Shahvir
     
    Last edited: Aug 20, 2009
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