holding on to an electric fence

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5 years 3 months ago #532452 by neil postie
Hi all
we recently had a guy on our farmlet that I warned of being careful of the electric fence coz it hurts. He gradded hold of it, held it for a good 5 seconds without even a twitch and told me it wasn't so bad. I asked "what the hell", he said "you have to do it right"
Someone on tv's 7 days said the same thing last Friday. Anyone know how? Its a hell of a party trick. Also our fence runs at 7.8 to 8.2 Kv, it hurts alot

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5 years 3 months ago #532453 by Stikkibeek
It might depend on what he is grounding with. What did he have on his feet?

Did you know, that what you thought I said, was not what I meant :S
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5 years 3 months ago #532454 by neil postie
thought of that. but they were regular work boots, he worked for a roading firm so I dought they were anything special

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5 years 3 months ago #532455 by Rokker
A lot of work boots these days have electrically insulated soles. Get him to try the same trick in bare feet!

Do NOT cross this paddock! ... Unless you can do it in 9 seconds, 'cos the bull can do it in 10!
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5 years 3 months ago #532459 by Cigar
Some people say the shock is less if you grab it tight. Some of the worst shocks I have had have been when I have barely touched the fence, but I have had some beauties grabbing it too.
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5 years 3 months ago #532462 by tonybaker
yes it's true, if you have dry gumboots you can do it. I did it once when holding a wire up for some visitors, not realizing the fence was on. I felt nothing but they sure did!

5 acres, Ferguson 35X and implements, Hanmay pto shredder, BMW Z3, Countax ride on mower, chooks, Dorper and Wiltshire sheep. Bosky wood burning central heating stove and radiators. Retro caravan. Growing our own food and preserving it. Small vineyard, crap wine. :)
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5 years 3 months ago #532464 by Rokker

Cigar wrote: Some people say the shock is less if you grab it tight. Some of the worst shocks I have had have been when I have barely touched the fence, but I have had some beauties grabbing it too.

Partly true, Cigar. Touching very lightly is more likely to result in an arc, causing a pin-point burn as well as the shock, so would be more painful. Wet or sweaty hands also results in a more powerful jolt. But yes, dry gumboots will prevent a shock because they electrically remove you from earth, just as a bird can perch on a 110,000 volt power line. It would only get a shock if it managed to have one leg on the wire and the other on the ground. Not many birds can do that!!

Do NOT cross this paddock! ... Unless you can do it in 9 seconds, 'cos the bull can do it in 10!
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5 years 3 months ago #532466 by tonic
My Dad would always check the fence by standing on one foot and grabbing it tight. He said the shock was worse if you touched it lightly. I wandered up to him one day when quite small and touched him while he was doing it, and got a good wallop. I can still remember it, it was pretty traumatic to reach for Dad and get pain. To this day I can't test fences, not even with a blade of grass, even the thought of it makes me shiver. My son used to wander up to fence tapes, pick them up and walk under them when he was a preschooler. He would stand holding a fence whilst his arm twitched in time with the shocks and not appear to notice. Until one day he walked into a fence tape, in the rain, without a top on and it got him on the throat. That was the end of him touching electric fences!
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5 years 3 months ago #532467 by spark

Rokker wrote: [SNIP]But yes, dry gumboots will prevent a shock because they electrically remove you from earth, just as a bird can perch on a 110,000 volt power line. It would only get a shock if it managed to have one leg on the wire and the other on the ground. Not many birds can do that!!

Not so likely on a 110kV line due to the large clearances, but at lesser voltages birds can sometimes end up creating a fault, which is why you sometimes see anti-perching spikes attached to cross-arms etc (large bird could otherwise perch on cross-arm, and if it touches the wire when it stretches its wings, it could create a ground fault from it's wingtip to the cross-arm - BANG!)
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5 years 3 months ago #532468 by Rokker

spark wrote: Not so likely on a 110kV line due to the large clearances, but at lesser voltages birds can sometimes end up creating a fault, which is why you sometimes see anti-perching spikes attached to cross-arms etc (large bird could otherwise perch on cross-arm, and if it touches the wire when it stretches its wings, it could create a ground fault from it's wingtip to the cross-arm - BANG!)

Absolutely! Kentucky Fried Seagull !! :evil:

Do NOT cross this paddock! ... Unless you can do it in 9 seconds, 'cos the bull can do it in 10!
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5 years 3 months ago #532474 by neil postie
Hi all thanks for the input, it would seem dry boots and holding on tight is the way to go. Now we need someone we can trust to do it, volunteers?

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5 years 3 months ago #532482 by Hawkspur
Not quite on topic, but following one of the frays of this thread:
There was a campaign years ago in the USA, which I believe succeeded, to phase in wider spaced power pylon arms. The new spacing was a bit wider than the wingspan of the bald eagle.

Quite a few were getting fried as they took off from the very handy perches.

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5 years 3 months ago #532522 by spark

neil postie wrote: Hi all thanks for the input, it would seem dry boots and holding on tight is the way to go. Now we need someone we can trust to do it, volunteers?


Might as well be me, except that I am [strike]chicken[/strike] respectful when it comes to electricity, so I used a flash tester instead of an electric fence!

So, I took one of my gumboots, and put a long bare copper wire and about 3L of water inside it as a human foot simulant (the tap water here is conductive enough for this test). My gumboots are in used condition, dirty, but are not worn out, and do not have any holes in them, etc.

The first test was placing the gumboot on an earthed conductive surface (simulating standing on the ground) and then applying 5 kV AC (~ 7 kV peak) to the copper wire/water inside the gumboot. This resulted in a leakage current of 0.16 mA (or 0.16 thousandths of an Ampere), allowing for 2x feet/boots on the conductive surface, the resulting 0.32 mA current might be perceptible, but wouldn't be particularly unpleasant (more of a tingle rather than a shock).

The second test was partially immersing the gumboot in "ankle deep" earthed water before again applying 5 kV AC. This time the leakage current was significantly higher at 1.43 mA, or 2.86 mA for 2x feet/boots, which you probably would feel, but which would be nowhere near as strong as a regular "good belt" from an electric fence.


Limitations of my test is that your foot probably won't fill the gumboot as well as water does (less contact with inside of boot reduces capacitance between "foot" and ground), and that an electric fence charger has significant high frequency output which will couple through the capacitance between a booted foot and the ground better than 50 Hz AC will. I wouldn't be too surprised if these two factors largely negate each other.

Thus I will conclude that while wearing a pair of gumboots in good condition, you will probably get away with touching an electric fence (but nothing else at the same time!) whilst standing on conductive ground.
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5 years 3 months ago #532523 by Muz1
Wet leather boots are NOT insulated.

Everything Must be Somewhere

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5 years 3 months ago #532524 by spark

Muz1 wrote: Wet leather boots are NOT insulated.

Yes, wet leather is a passable conductor at these voltages (and dry leather isn't really a very good insulator either...).
If you have ever seen "leather" lines-person’s gloves up close, you might have noticed that they have a rubber glove inside them - the inner rubber glove is the actual insulation, the leather outer glove is only there to protect the rubber inner glove from mechanical damage eg:
www.fastenal.com/products/details/1044083

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