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Capacitor and leakage current

  1. Apr 8, 2010 #1
    1)Suppose I've taken two conductor plate in parallel and air is in between them.now if i apply a voltage across them then capacitance would form in between them and there must be some leakage current but they are very negligible that's why it cant be detectable.But if apply 500KV across two small plate then the amount of leakage current must be higher isn't it?is that amount of leakage current high enough to get shocked if I put my hand between the two plates?

    2)leakage current flows by jumping of electrons.what type is it dc or ac?or its not like that?

    3)what is the relationship between capacitance and leakage current?are they proportional or inversely proportional?

    all these madly questions arose in my mind from the following thinking:Above us there is high voltage transmission line;below there is ground.Then in the middle there is air.So capacitance will form and also there should be some leakage current.So it would be a frequent incident that we people getting shocked.But we don't feel any shock,why? Then I answered myself: this leakage current is very very negligible so we don't feel any shock,if the amount was high then we definitely feel shock.But we are logically fortunate this
    amount is not high.

    But still I am not confident about my own answer.that's why I am asking these to you.
  2. jcsd
  3. Apr 8, 2010 #2


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    Science Advisor

    There is some discussion about whether it is safe to live near high voltage power lines.

    There is no leakage current until the voltage becomes high enough to cause an arc-over between the power line and ground. This should never happen unless the power pole is broken and the line gets close to the ground.

    However, the power line carries AC and this is constantly charging the capacitance to ground with a different potential. So, there would be some current flowing in the air dielectric because of this.

    On the other hand, there are usually 3 high voltage wires. The 3 phases in the 3 lines tend to cancel each other out as far as charging the capacitance to ground is concerned, because they are 120 degrees out of phase with each other. So, their net voltage will be close to zero.
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