How come birds don't get electrified when they perch on wires?
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Boris Johnson's Press Secretary, Fri 11 Sep 2009, 17:35,
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no honest, I've always wondered this
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Boris Johnson's Press Secretary, Fri 11 Sep 2009, 18:00,
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well it's your lucky day then :)
The Almighty Beev has answered it down there, sort of.
Just to add: the wires are at 240v. the birds are touching the wires (but nothing else) therefore also at 240v. there is no potential difference between the 2, both are at 240v. If the birdy touches the ground (which is at 0v) at the same time then the birdy would be completing a circuit between the wire (at 240v) and earth (at 0v). Potential difference of 240v, therefore current will flow. Birdy bbq.
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spesh., Fri 11 Sep 2009, 18:06,
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Do you actually want to know, or am I setting myself up?
It's because they don't create a favourable route for the electricity to travel to. Bird is higher resistance than wire, so the electricity just travels through the wire.
They would get fried if they connected the wire to ground - their bodies then make a better path than air, so the juice flows through them. Apparently you see this with squirrels - they happily run along power lines until they hit the end, where they form a (short lived, high voltage) connection between the line and Earth.
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TheAlmightyBeev, Fri 11 Sep 2009, 17:46,
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although......
if the birdy touched 2 of those wires at the same time then bzzzzzzzzzzzt. The top 3 are the red/blue/yellow phases (all at 240 or 415v, but not simultaneously), 4th down is neutral, bottom is earth.
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spesh., Fri 11 Sep 2009, 17:54,
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Does the voltage matter?
I have no idea of this, but my grandfather's maxim was "Volts jolt, but mills [i.e. milliamps] kill". Was that bollocks, then?
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Enzyme is powered by sunlight, Fri 11 Sep 2009, 19:16,
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Yes
Your nervous system is basically an electric circuit. Putting too much current through it will burn it out, bit like if you accidentally plugged your house into 25KV it'd catch fire. That is why electric fences, tazers etc give out several thousand volts. The current is almost non-existant, so it isn't fatal.
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Greenbat, Fri 11 Sep 2009, 22:52,
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The analogy my old man gave me was this:
Say you're standing in front of a water pipe. The voltage is the speed of the water rushing from the pipe and striking you. Whether slow or fast, it's unlikely to kill, though it's going to give you a pretty nasty sting at higher voltages.
The current is the circumfrence of the pipe. Once that starts increasing, all of a sudden the sheer volume of water becomes overwhelming whether voltage is high or not, and it can be pretty damn deadly.
That's not word for word what he told me years ago, but I hear that as an analogy goes it's not inaccurate.
(, Fri 18 Sep 2009, 19:05, Share, Reply)
Not sure I completely agree
A volt is a Joule per coulomb (i.e. charge carrying bucket). An Amp is a Coulomb per second (i.e. number of charge carrying buckets per second, so this is the water speed in the analogy). The charge per bucket is the width of the pipe. Regardless, a lot of either Volts or Amps is a bad thing as VxA = Watts, i.e. power.
www.dribin.org/dave/blog/archives/2003/12/29/amps_vs_volts/
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gingerbenji wrote a book http://goo.gl/8UiGjd, Fri 18 Sep 2009, 23:01,
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So,
its not because they have little rubber pads on their feet then?
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@RBFesquire Good luck b3ta, was nice knowing you. So long., Fri 11 Sep 2009, 19:33,
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