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If you touch just one phase..

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OutToLunch

New Member
depends. are your feet on the ground? then yes.

but, if you fell from a hot air balloon and grabbed a high tension line on one of the large transmission lines and were hanging there in the air only holding that one wire you'd be fine. well... fine being relative, of course.
 

Boncuk

New Member
Generally nobody is electrocuted by just touching a life wire.

Birds would fall off fried of a high tension wire if they closed a circuit to ground.
(Their legs are too short to touch ground. :) )

There has to be current flow from life to neutral or earth to get electrocuted. The current has to have a certain strength (>15mA at 230VAC mains).

Standing on a wooden ladder and touching a life wire won't do any harm.

Current flow does not depend on the number of life wires, but on current flow only.

You might want to see the proper technique to get electrocuted. :confused: Check out the attachment.

Boncuk
 

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Mr RB

Well-Known Member
...
Standing on a wooden ladder and touching a life wire won't do any harm.
...
You might want to try that sometime before you sound TOO confident about it. ;)
 

Boncuk

New Member
You might want to try that sometime before you sound TOO confident about it. ;)
I did it and I'm still alive. (Of course the ladder must be dry. :) )
 
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SPDCHK

Member
I did it and I'm still alive. (Of course the ladder must be dry. :) )
I agree you won't be electrocuted, but you might still get a little shock. Your body has to reach the same potential as the live wire. No current will be flowing continuous, but just enough to let you know you touched something shocking :eek:
 

Pommie

Well-Known Member
Most Helpful Member
I once accidentally worked on a live circuit whilst on a wooden ladder - I pulled the wrong fuse. Didn't notice anything until I earthed myself to the cable box - then it hurt.

Mike.
 

Hero999

Banned
Actually you don't have to be earthed or be touching another wire to be fried.

If depends on the frequency. At low frequencies your capacitance will be negligible so only a tiny current will flow, at high frequencies your capacitance will be significant so a high current can flow giving you a severe burn. Luckily higher frequencies don't shock you so much but the burns can be pretty nasty.
 

Boncuk

New Member
Actually you don't have to be earthed or be touching another wire to be fried.

If depends on the frequency. At low frequencies your capacitance will be negligible so only a tiny current will flow, at high frequencies your capacitance will be significant so a high current can flow giving you a severe burn. Luckily higher frequencies don't shock you so much but the burns can be pretty nasty.
The higher the frequency the better the chance to get sterilized, but not electrocuted.

The radar of the RF4-E (Phantom) has a pulse power of 60KW which you don't notice touching the antenna horn. After half a dozen of touches you won't have to take care of birth control anymore. :)

I once approached the antenna mast of a LORAN-transmitter. My friend (who maintained the station told me to jump towards the mast from 1m distance and hold on the metal).

At that distance my entire body disappeared in St. Elmo's fire, but it didn't hurt at all - just tickled a bit.
 

crutschow

Well-Known Member
Most Helpful Member
If the voltage is very high, such as a high tension power line, you can get noticeable current from just your body capacitance, even if you are not touching ground. I once saw a video of some workers working on an energized line from a helicopter. They approached the line in the air and then threw a wire across the line from the helicopter to equalize the voltage. You could see an arc before the wire touched the line, just from the capacitance of the helicopter.
 

alphacat

New Member
You say that if you stand barefoot on the ground and touch the live wire then current would flow through your body.
But the ground resistance is very large, so isnt it still considered an open circuit?
 
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crutschow

Well-Known Member
Most Helpful Member
You say that if you stand barefoot on the ground and touch the live wire then current would flow through your body.
But the ground resistance is very large, so isnt it still considered an open circuit?
The ground resistance depends upon how moist it is. For even low values of moisture the resistance is likely low enough to cause a lethal current through your body from a power line.
 

tcmtech

Banned
Most Helpful Member
A buddy of mine has had several cats do the live wire dance on his pole transformer for his farm over the years.:(
They come down just like that dummy on the train did! Crispy and flaming!:eek:
 
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BrownOut

Banned
A buddy of mine has had several cats do the live wire dance on his pole transformer for his farm over the years.:(
They come down just like that dummy on the train did! Crispy and flaming!:eek:

Welcome back! :)
 

smanches

New Member
I agree with crutschow. My uncle worked as an electrician at the mines where they run 100KV. When I was a kid I asked him why the birds didn't get electrocuted, he went on to explain they weren't grounded. I do remember asking him if I could hang from the wires, and he explained that because we're so much larger than the birds, the capacitance of our bodies could still be enough to kill us, even not being grounded.

And then a college kid proved it to us a number of years later. Stupid fraternity dare. And that was only on the normal street wires, which I think are only 4KV.
 

tcmtech

Banned
Most Helpful Member
One of my college professors had a video of a guy in a bucket truck in some foreign country that took a hit off a 69 Kv main line while trying to hook up an illegal substation for a small village.
An uninsulated truck and and apparently a fairly conductive hot stick (broom handle) was used! :eek:

He basically exploded, the fiberglass bucket bursts into flames, the truck tires explode, the boom operator gets severe burns from the hydraulic system when it blows up and shoots flaming oil all over the truck. The operator did manage to jump free and run away while the whole truck burned up in a matter of a few minutes. By the time the emergency crews get there the whole truck had burned up. :eek:

They said the bucket guy was half his regular weight when they buried him.:(:eek:
 

Hero999

Banned
I doubt you can be electrocuted by touching a single phase of an HT line, if you're not grounded or connected to a huge metallic object.

Assuming 100pF in series with 1k (the standard human body model) and the US power line frequency of 60Hz. We can ignore the 1k for now because it'll be insignifcant compared to the capacitance at 60Hz.

[latex]Z = \frac{1}{2\pi FC}= \frac{1}{2\pi \times 60 \times 100\times 10^{-12}}= 26.53 \times 10^6 \Omega[/latex]

26.5M is one hell of a high impedance!

For a 100kV line:

[latex]I = {100 \times 10^3 }\times {26.53 \times 10^6} = 3.77 \times 10^{-3}A[/latex]

3.8mA might give you a small shock but it certainly won't kill you, more likely than not you'll just swear.

What about the power dissipation? Will 3.77mA at 100kV burn you? No, it won't.

Why?

Because you only need to take the current and resistance into account, the rest is just reactive impedance.

[latex] P = I^2 R = (3.77 \times 10^{-3})^2 \times 1000 = 14.21 \times 10^{-3}W[/latex]

14.21mW isn't going to burn you.

In the instances you're talking about the electricity was finding a path to earth, one way or another. The fibre glass bucket wouldn't provide good enough insulation, a spark could easily track down the side. The helicopter is a huge metalic object with a much higher capacitance than a human so a lethal current could flow.
 
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