Small birds can happily sit on high voltage pylon cables, but I’m pretty sure if I tried to perch in a similar fashion, I’d fry. I’m guessing that small birds can get away with it because the electric field strength* over their short bodies is sub-lethal, but there must be a size of bird that can’t get away with it. Can an albatross perch on a 25,000 volt wire, or will it be fried?
The smaller birds must get a bit of a tingle too. Is there any advantage (or indeed pleasure) in this, similar maybe to the way some birds will sit in chimney smoke to fumigate ticks etc?
*In this particular case, the bird sits on a single high-voltage wire, a safe distance from other wires or the ground. The wire’s electromagnetic field will induce a voltage across the bird’s body, but there’s no direct path to ground, and the bird is insulated from everything except the wire.
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Can an albatross perch on a 25,000 volt wire, or will it be fried?
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As far as I’m aware, any creature, including yourself (rather you than me…) can sit on a high voltage wire safely, unless you are near enough to the ground or grounded object for the electricity to arc.
This isn’t the case with high EM fields, so don’t go hang-gliding under pylons, even outside the arcing distance. Essentially, any electric current through a conductor will generate an electric field around it. From the tiniest nerve impulses in your body to lightning strikes on Jupiter; same thing, different scale. Electric field strength can be measured in terms of volts-per-metre. Say I was standing under a pylon that had an electric field strength of 200 V/m, and I stuck a 1m fluorescent tube in the ground. Would it light up? Artist Richard Box says yes!
I remember reading about repair crews that (apparently) work on live overhead power cables, by thoroughly isolating themselves from ground and working with everything at the potential of the conductor. Can’t find anything on this at the moment, but I’m sure it was from a reputable source and that I didn’t imagine it.
I think you could hang one-handed from a high-voltage wire as long as you weren’t close enough to anything for it to arc. If you used both hands… there might be enough of a difference in potential between your hands for you to get zapped. Same for if you sat on it.
Cheers Mangetout, I didn’t know about the helicopters and conductive suits for working on live pylons. That’s just so cool! Athough the Wiki quote “Barehanded live-wire work can theoretically be done at any voltage” should really read “Barehanded (but swathed from head to foot in live chainmail) live-wire work can theoretically be done at any voltage”.
So what about creatures that don’t comply with safety regulations? Anyone seen a duck on a pylon? Or owl, eagle etc - anything bigger than a sparrow.
There’s an old bird+powerline story around, and I’ll tell it to you with no vouching for its truth. It illustrates the cleverness of crows.
A guy whose job it was to walk under the high tension lines to pick up and count the dead birds wasn’t finding many. One day, he started his trek earlier. He found a lot more dead birds. He kept up his early starting, and after a few days, the crows adjusted their own schedules so they could get to the carrion before he did. The count went back down to its previous level.
If there’s an IMAX theater near you showing a film called Straight Up: Helicopters in Action, you can see a guy working on a high tension line from a helicopter. It’s pretty cool.
As the helicopter approaches the wire, the technician, who is going to actually going to climb out and sit on it, is sitting in the door of the chopper. He uses a wand to discharge difference in potential between them. These big arcs jump between the wire and the wand. I saw a clip from the film while it was in production, and I told one of the filmmakers that they had to fix that scene, because the arcs looked really fake. I thought they had used some cheap effects. She told me that was the real thing.
Turns out that the way we expect electrical arcs to look and behave is based on the way Hollywood movies do them. Which is really fake.
High voltage linemen work on high voltage lines all of the time without any special equipment or “conductive suits.” They get onto the line by a couple of methods. One of them is by an insulated bucket. The bucket is brought near the line and the lineman wearing insulating gloves reaches out to the line with a probe that is connected to the bucket and himself. After the probe is connected to the line it and the bucket and the man are all at the same potential. A bosuns chair can then be placed on the line and the man can sit in the chair and roll back and forth on the line to do whatever needs to be done. At the end he gets back in the bucket and is lowered to the surface being careful to touch the surface with the probe before getting out of the bucket.
The other method is to put the man on the line by helicopter. All other steps in the process are the same as with the insulated bucket.
Wow. Has anyone addressed the OP yet? Not the “My grandma was in a chainmail suit and hung around until the Depression was over” type posts.
It’s an interesting question, and I’m sure the interesting answers involve the anecdotal stories you are telling… but you are still not answering the question.
And you call this factual? I’m not trying to troll or be difficult, but I mean c’mon! I was expecting answers from those that practice science and deal with such things.
The question has been adequately and factually addressed. What more do you want, the exact voltage that will appear across the albatross’ legs? If so, I can calculate it for you, but I fail to see how it would add significatly to the already excellent answers.
As long as I don’t have an pacemaker or a coil of wire around me, the EMF from a transmission line is not a big immediate problem. 50 years of living directly under one I’m not sure of… Anybody done that?
Yep, literally thousands. Most notably in Australia where there are large swathes of essentially treeless land with thousand of miles of high tension electric trainlines. The power lines and pylons have become the favoured perches of all the carnvorous birds including hawks, butcher birds, kookaburras and even the occasional eagle. And these are lines operating at something like 25, 000 volts. There’s never any problem for the birds.
Interesting side note though, bats get fried on power lines all the time because they land by hooking one line with a wing and swinging up onto the other line with their feet. The difference betwen the two lines is almost always high enough to fry them.
The OP is misinformed on why birds don’t get electrocuted–you too can touch a high-voltage line, as long as you’re not touching any other wire out of phase or anything grounded. Say you put a trampoline under a high-voltage line, and bounced on it higher and higher until you could grab onto the power line and hang. You could hold onto the power line with no harmful effects* as long as you didn’t touch any of the other wires, or anything with a conductive path to ground.
Some years ago in the US (during the 70’s I think) a whole bunch of high-voltage wires in the western states had to be replaced because they were killing condors, which became a federally-protected species. The way that the electrical poles were made, the different wires were strung close enough to each other that a condor’s wingspan could reach across and touch two wires at once. The new poles mounted the wires farther away from each other. It was never the touching one wire that killed the birds, it was being able to touch two wires at once.
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*aside from perhaps a guest appearance on MTV’s Jackass
