Farmers Weekly Interactive

Hanging on the line

dead-sq.jpg

Grey squirrels. Love ‘em or loathe ‘em, you can’t help feeling sorry for this little fella – even though he spent the past few months raiding the so-called squirrel-proof bird feeders in a friend of mine’s garden.

As for what caused his premature demise, well, these power lines feed directly into Robert’s house, so presumably are 240 volts – enough to kill a full-grown man, let alone a small grey squirrel.

He appears to have been in the process of moving down the wires, and bridged the gap between them. Presumably this meant he became a conduit for the full 240 volts – certainly it “froze” him to the wires, as he’s been up there a week already.This has prompted much debate – as has been pointed out, this action would surely only prove fatal if there was a substantial difference in current between the two wires, or one was earthed?

Any sparkies who can shed some light on the subject please get in touch. Not that the answer will be much consolation to the squirrel in question.

Meanwhile, Robert’s photo seems to provoke one of two distinct reactions in everyone I show it to depending on people’s view of these creatures. Either “Ah, that’s a shame” or “Ha-ha, good riddance!”

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Tim Relf

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11 Responses to Hanging on the line

  1. Mike Saull April 7, 2013 at 9:42 pm #

    If you are running a sweepstake on how long the squirrel will be left hanging on the line, my guess is two complete run throughs of Tchaikovsky’s Nutcracker Suite, and a complete run through of Enya’s last album……….

  2. Andrew Blake April 7, 2013 at 9:42 pm #

    Come on Tim! To write about 240 volts alone as if they were something deadly is misleading. The static charge from combing one’s hair (which I can recall in case you ask) can run to several thousand volts, but is pretty harmless – unless you happen to be surrounded by a flammable gas. That’s because there’s almost no current (measured in amps) involved. It is the combination of volts and current that creates the power that can kill.

  3. tim relf
    tim relf April 7, 2013 at 9:42 pm #

    Hello Andrew,
    Afraid I still don’t understand – although that’s probably more a reflection on my non-technical brain than on your explanation! (I’m afraid I failed my physics O level.)
    Why exactly did it die then? I mean, I’m assuming it didn’t just happen to die of old age while it was on the wires!
    I’ve emailed those clever people at New Scientist in the hope that they can come up with a definitive answer.
    If we can increase the sum total of human scientific understanding, then the squirrel will not have died in vain!
    Tim

    Hi Mike,
    Thanks for visiting Field Day. Its nuts will either be cracked or roasted!
    Tim

  4. Adam April 7, 2013 at 9:42 pm #

    I think you have to be be “grounded” – have a connection directly to the earth – for the electricity in those wires to be dangerous. That’s why birds can happily roost on them.

  5. Kevin April 7, 2013 at 9:42 pm #

    To understand what happened, remember that current flow is between different voltage potentials. That’s the only requirement. You can be electrocuted by a downed power line just by the different voltage potential between your feet – there is a difference between voltage potential due to the resistance of the dirt, so electricity can run up one leg and down the other. That’s one reason why utility workers wear special insulated overshoes.

    In U.S. residential voltages, that difference in potential is around 120v line to ground, or 240v line to line. How? Because each 120v line is 180 degrees different from the other. When one line is 120v negative, the other is 120v positive, and visa versa. This gives a difference in potential of 240v. Since the ground essentially has a potential voltage of “zero,” the difference in voltage potential of each line, or is 120v measured to ground.

    (Important: Please note that you can have a difference in potential voltage between the neutral and the ground – NEVER assume the neutral or ANY is safe to touch!)

    In three-phase power, each phase is separated from the other by 1/3 of a cycle, so there’s a difference in potential voltage between each phase. That means anything that bridges that gap will conduct a current.

    How much current depends on what’s known as fault currents, and depends on such things as the electrical characteristics of the line, equipment, and what bridges the gap. It can be quite high.

    Please keep in mind that power lines run at a much higher voltage that 120/240v. U.K. residential voltage is around 240v. 2,000 volts, 7,200 volts, 14,400 volts and up to 46,000 volts have been used as distribution line voltage, and transmission lines start at 46,000 volts and go over 760,000 volts. And “just” 120v can maim and kill, too. Electricity isn’t something to play with.

    For the record, birds get nailed, too. Remember, all that’s needed is a difference in potential. Birds have been killed by bridging the gap between phase to neutral, or even phase to phase.

  6. Andrew Blake April 7, 2013 at 9:42 pm #

    Kevin,

    It seems I was wrong about ‘current’ then?

  7. Michael Holding April 7, 2013 at 9:42 pm #

    I think the reason is simply that birds fly and so arriving from above only need to touch a single conductor – so no circuit through tweety-pie. The squirrel, I suspect, takes a leap and ends up making contact with two conductors thus completing the circuit and ZAP.

  8. tim relf
    tim relf April 7, 2013 at 9:42 pm #

    The New Scientist is trying to help us explain the likely cause of death of the “Field Day squirrel” – you can see some interesting comments about it on its Last Word blog at:
    http://www.newscientist.com/blog/lastword/2007/09/squirrel-postmortem.html#nbicomments

  9. Andrew April 7, 2013 at 9:42 pm #

    Well iv just been for the second time been electricuted by 240 volts from my bedroom plug socket when re – wireing it without turning of the house power and im stil alive although i found this blog when searching to see if i could die luckly im still alive enough to writ this comment after been shocked by 240 volts from a live plug socket, did not want sent sharp pain straight up my arm then eventualy managed to let go of wires ik that you mucsels tense as mine did when you get electricuted so id say thats why the squirl is still there

  10. tim relf
    tim relf April 7, 2013 at 9:42 pm #

    Hi Andrew,
    Ouch, sounds very painful!
    Tim

  11. Bryan Hunt April 7, 2013 at 9:42 pm #

    Okay, basically, why does this happen?

    In order to be shocked, you need to have a complete current run through you. So, you can get shocked if you’re grounded, or if you touch both the positive and negative power lines.

    By my house, I see squirrels run along these lines all morning. They do not die because they run on one. But, when you touch both, you complete a circuit and get shocked.

    This squirrel probably had his feet grabbing one wire and then he grabbed the other one and got shocked.

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