Is static electricity dangerous?

Discussion in 'General Science & Technology' started by IamI, Sep 26, 2007.

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  1. IamI Registered Member

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    Hello guys, I was wondering all the time if static electricity is dangerous, you know these static-electric generators like Van de Graph and others that produce high voltage, like 50kv with very little amperes,

    I have searched alot but I still dont know if it is dangerous or not with such high voltages 50kv with almost no amperes

    thanx
    Kalle
     
  2. mikenostic Stop pretending you're smart! Registered Senior Member

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    If it discarges with enough current to kill you, then yes they are dangerous.
    And if the amps are low but the voltage is high, you're still going to feel it. Stun and Tazer guns work on a high voltage/low current basis.
     
  3. shichimenshyo Caught in the machine Registered Senior Member

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    lightning is a form of static electricity so yes
     
  4. IamI Registered Member

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    at HOW much currents are they deadly at 50kv for exampel? is it dangerous if it was few millieamperes?

    thanx
    Kalle
     
  5. Reiku Banned Banned

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    11,238
    Do you mean that the electromaginetic is a potential, then we will find every result to originally arise the gravitational force? It plays importance.
     
  6. andbna Registered Senior Member

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    There are allot more amperes in a lightning strike, it's measured in kiloAmps, to give you an idea :p

    The maximum safe current is considered to be 5 milliamperes. Voltage becomes a factor when the number of amperes is limited by resistance (that is, when dealing with sources that can produce a dangerous amount of amperes, your bodey's resistance is the only thing protecting you) In your case, volatage is high eanough to easily guarantee a current can pass through you.

    As for a Van de Graaf generator in specific, they are usualy harmless, it's a typical highschool physics demonstration to have a student put their hand on one after all. Of course, if you come too near, or remove your hand while it's on, you can get a painfull shock from the heat cause by a spark. Nothing seriouse, but could cause some external burns at worst.

    Please note however, I am no doctor :p
    -Andrew
     
  7. Reiku Banned Banned

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    11,238
    ''Hello guys, I was wondering all the time if static electricity is dangerous, you know these static-electric generators like Van de Graph and others that produce high voltage, like 50kv with very little amperes.''

    Static electricity turns out to be a very important. It was another side of then available coin. There is massive potantial created for the being well-ahead if it determined for the future! We are given a certain amount of heartbeats.
    We are given a certin amount of time. And because of this, forces like electromagnetism turn out to be good principles for life, since is mediates the electrostatic repulsion field, stopping every solid material system from simply passing through each other. The field gives rise to materialism.

    ... perhaps the Higgs Boson is not needed for matter? Might we take relativity really seriously, and say that if a system contains energy (E) is enough of a reality to submit a presence of matter through the equivalance principle (E=M)c^2?

    We will find out soon enough... ...

    Reiku
     
  8. scorpius a realist Valued Senior Member

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    hey I just had a crazy idea,if too much electricity can kill,could small amounts of it help to cure,... ,to kill something like cancer cells maybe?
    mind bogling possibility eh?
    maybe I should apply for a goverment grant to research this idea!:D
     
  9. IamI Registered Member

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    "The maximum safe current is considered to be 5 milliamperes. Voltage becomes a factor when the number of amperes is limited by resistance"

    so you mean even at 50 kv with only 5 millieampers it wont be dangerous then? or it is a rule for even much hiht voltages?


    Van de Graaf generator in specific, they are usualy harmless, it's a typical highschool physics demonstration to have a student put their hand on one after all. Of course, if you come too near, or remove your hand while it's on, you can get a painfull shock from the heat cause by a spark. Nothing seriouse, but could cause some external burns at worst.


    hmm, how much does van de graaf generate ?


    thanx alot guys
    Kalle
     
  10. kevinalm Registered Senior Member

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    As electronic techs we are taught that what is dangerous is current x duration. If 0.1 amp sec (coulomb) crosses the heart muscle V fib can occur. So 1 amp for 0.1 sec or 0.1 amp for 1 sec, etc. can possibly kill you. High voltage is a concern because once you get past the outer layers of the skin (like getting your hands wet) the resistance of the human body is only a few hundred ohms, and it doesn't take much voltage to push a dangerous current x duration in a very short time.
     
  11. Read-Only Valued Senior Member

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    That's what I was taught too, Kevin. Plus, there's a wild card in the deck waiting to get you: it also depends on precisely where the heat is at that moment in it's cycle. I don't recall if it's the pumping, resting or refilling stage but one of them is MUCH more dangerous than the rest. And there's no way, of course, to know where it is at any given time. So the best rule of all is to simply avoid HV by using safe working practices.
     
  12. IamI Registered Member

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    Kevin, so you mean we are pretty low resistors and very little currents like 1 ampere can kill us if it gets to our body??!!! I play everyday with rc models toys airplanes with over 16 amperes at 11 volts and nothing happens?

    I think I know why, let me guess: IT is the high voltages that let the weak current get to our body and kill us? right me if I am wrong, which means that low voltages with 15 amperes is okey but 30kv with 1 amperes are deadly?
    kalle
     
  13. kevinalm Registered Senior Member

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    993
    The outer dead layers of the skin are pretty good insulators when intact and dry (10 or 20 kohm or more). But get your skin wet or punctured and you are basically a sack of salt water. A rather good conductor, a couple of hundred ohms maybe. Now at 12 v you aren't likely to get hurt, as the current would be limited to perhaps 1/20 amp, and would have a sec or more to get loose. As a rule of thumb I start to get nervous around 30 or 40 v.

    Now the path through your body is important. The danger is mainly current flow through the heart muscle. In one hand and out the other or in one hand and out a foot, is realy bad. Which is why we are also taught to wear rubber soled shoes, stand on dry floors, and to always keep one hand in our pocket when probing about in high v /high energy circuits.

    And _never_ intensionally take a shock. It's kind of a matter of professional pride among etechs to be able to say 'oh, its been years sinced I last got shocked'. In fact, some employers would fire your butt for intensionally taking a shock.
     
  14. kevinalm Registered Senior Member

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    993
    I think it's the resting phase between beats,iirc. A blow to the chest can also do it, at the critical time, in between beats or whatever the critical time is. Every so often some little league kid gets killed that way.
     
  15. IamI Registered Member

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    so basicly even if we are dealing with low millie amperes at very high votages they can get into our body even if we dont have wounds?


    wonder then just why vna de graaph aint dangerous
    kalle
     
  16. Read-Only Valued Senior Member

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    10,293
    Very simple - not enough current.:)

    A van der Graff (correct spelling) generator only produces current in the microamp range. That's 10 to the -6 power. Very, VERY low current! One microamp is 0.000001 amp - get the picture now?;)
     
  17. Echo3Romeo One man wolfpack Registered Senior Member

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    1,196
    Yep, it is more dependent on the size of discharge delivered than anything else. Voltage and peak current just help you estimate a ballpark of that figure based on the nominal conductance of skin and tissue.

    Static electricity as we commonly think of it isn't dangerous, unless you happen to be working in an explosive environment or something.
     
  18. Formula1000 Registered Member

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    How Stuff Works has an article on Tasers. It explains high voltage situations which are less than lethal.
     
  19. MetaKron Registered Senior Member

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    The current from a Van de Graff generator is stored energy. You have a globe of some kind of conductor that is charged with electrons. Even a small amount of energy can add up to multiples of one ampere at thousands of volts for a short duration. The bigger the Van de Graff generator, the more energy it holds. Such generators have been used to generate artificial lightning. How dangerous it is depends on how large it is.

    Another simple energy storage device is the Leyden jar, which works on similar principles. A jolt from one of these can kill you.
     
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