240V overhead line NOT

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I was watching Spike channels's 1000 ways to die. Some kid hit an overhead line with a sword. Spike said 240V killed him. If you hit an overhead line with a sword, the voltage would be 120V
I know it is just TV. Just saying. :)
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Unless it was one leg of a three phase and 277 go him. TV, especially the news is notoriously wrong on so many little facts like that. In our town thee was a fire and the reporter said "the fire was so hot it melted the aluminum siding on the building across from it" No it was vinyl siding (I was there and saw it) and the temperature difference needed is a few hundred degrees.
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On Sat, 20 Mar 2010 23:22:19 -0400, "Ed Pawlowski"

Which it usually is. 240/277, I think they're pretty close
But i agree that the news makes loads of mistakes, especially tv new. The few times I've been present at something that was on the news, they made at least one clear mistake.

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Metspitzer wrote the following:

So, no one has ever been electrocuted by working on their own household electricity?
--

Bill
In Hamptonburgh, NY
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As in electrocuted to death in the absence of an underlying health condition? Having myself received 120V a few times, I'd be interested in that, too.
120V feels like the world's biggest, wriggliest worm crawling through you at about 500 miles per hour. But I'm not dead. I think.
We just got a new electric forklift at work. The guy who installed it said he'd been shocked once while doing a similar installation, working on a 600V panel. He didn't specifically say, but I'm guessing he took one leg of the power (200V+?). He said he could not at first let go of the screwdriver he was using in the panel; his hand muscles clamped down hard on the screwdriver handle, and it took considerable effort to un-clamp them. The next day his shoulder felt like it had sand in it when he rotated it, but that eventually went away.
--
Tegger


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Tegger wrote:

This article puts deaths caused by 120VAC electrocution at about 12% of the total electrocution deaths: http://tinyurl.com/ye7ghwk Look almost at the bottom here: http://tinyurl.com/ybtutkj There is a breakdown of the voltages involved. The current needed to stop a person's heart is measured in milliamps.
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Dean Hoffman wrote:

That is why they beat into us as young kids- any time you are working near or on hot panels. stuff your left hand down the back of your pants. It improves your odds a little if the current path isn't arm to arm. Don't know if it actually true, but it SOUNDS plausible. And if nothing else, the teaching makes you remember to pay attention to what you are doing, and plan your moves before you make them.
--
aem sends...

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On 3/21/2010 10:15 AM, Tegger wrote:

Just takes the proper path to do it and only ~ 100 ma.
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George wrote:

It takes an order of magnitude less than that to send the heart into V-fib. That means if you don't have a means to restore normal rhythm, you die.
Jon
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On 3/21/2010 12:10 PM, Jon Danniken wrote:

Yes, If you have a direct path to the heart. 100 ma is the most it takes if you have a good external path (arm to foot etc).
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It's not the voltage that kills you, it's the current.
For example, a typical static shock can be thousands of volts, but the current is so low it's usually nothing more than a quick "ouch" (though it's still enough to destroy some sensitive electronic circuitry).
I've been shocked by 120V a few times in my life as well. The reason I lived to tell about it is because there was enough resistance through my skin, clothing, shoes, carpeting, or whatever to keep the current low (combined with the reflex jerk that pulled me away from the wire).
Think of a bird sitting on major power transmission line. There may be thousands of volts in that wire, but the resistance to ground (i.e. the air) is so high that it can sit there unharmed.
Common 120V household electricity can easily kill you if the resistance to ground is low enough. i.e. dropping a hairdryer in your bathtub, or changing a fuse while standing barefoot in a puddle of water.
Anthony
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I seem to remember reading somewhere the lowest voltage causing a fatality was 40V. But 10mA through the heart will stop it. We have 240V single phase/415V three phase in the UK and also in most of Europe. However we also have Residual Current Circuit Breakers the detect more than 30mA leakage to earth and cut off power in less than 1/2 cycle.
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On Sun, 21 Mar 2010 12:46:20 -0700 (PDT), harry

Yes, it's the current that kills (if enough of it passes through the right path), but the voltage creates that current:
I (current) = V (voltage) / R (resistance)
The lower your skin/body resistance (wet skin has much lower resistance than dry skin) or the higher the voltage, the higher the current.
Lower voltages often aren't as dangerous for 2 reasons:
1) Whatever your body's resistance, the current is lower
2) The low voltage is often supplied by batteries or transformers with lower current capacity (high internal resistance) -- if your body tries to sink a lot of current (low body resistance), the voltage drops significantly. On the other hand, a car battery can supply hundreds of amps at 12V, and you could easily electrocute yourself with one if your body resistance/path is right.
Josh
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Josh wrote:

You can, of course, cite a few instances of people being electrocuted with 12 VDC?
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You can get thousands of amps from the mains under fault conditions, even in the house. I never heard of anyone killed with a car battery. I did see a seroius injury when someone shorted out a car battery with a metal wrist watch strap. He had a serious burn right round his wrist.
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On Mon, 22 Mar 2010 06:00:13 -0500, Dean Hoffman

Of course not, this is Usenet!
Upon research, I'll retract most of that (especially the "easy" part) and say that generally, 12V isn't considered enough to break the skin resistance -- some references say 48V is required for *dry* skin, with wet skin less but still not enough to kill. I can buy that.
However, almost everything I've read is talking about *touching* the terminals with your skin in the way -- if you punctured the skin through to blood/other fluids, you create a much lower resistance path that I believe could be deadly. Imagine falling on the sharp edges of the jumper cables, for instance. I can't find reference to specific instances, but I wouldn't chance it myself...
The bigger risk with a car battery is burns (shorting across a ring/bracelet and a wrench) or explosion/acid burns.
Josh
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I've heard stories about burns caused by watch bands, jewelry and such. It's always someone who heard about the guy who..................... Harry's is the first eye witness account I've heard. Mechanics I know don't wear anything metal on their hands or arms. I do irrigation wiring. We can run anything under 30 volts (AC usually) into a panel without going through a disconnecting means.
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news:0469b86f-2567-4491-abcd-> I've heard stories about burns caused by watch bands, jewelry

While not electrical, I stopped wearing my wedding band for anything more than just "going out," as a very young married man. During college, I was the building electrician for our highrise married student housing complex. One day, I'd left the toolbelt in the roller kart and had left for class. As I was crossing campus, I spotted a fellow who had been drilling a form with a 5/8" augur bit. He was dancing around and holding his hand. I ran over and spotted the squirting blood. The bit had caught under his wedding ring and had entered inside the ring: cutting off his finger. I helped him wrap the hand in his shirt and my handkerchief, picked up the finger and ring from the ground and helped the poor guy over to the infirmary. This was the 60's and sewing a finger back on wasn't in the cards. When I got back to our apartment, my wedding ring went into the jewelry box.
--
Nonny

The time to repay our Congress and
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Come to think, I saw another accident with a battery. This guy disconnected a battery from a charger without first turning the charger off. (ie took the crocodile clips off the battery terminals). There was an exposion that blew the top off the battery and showered him with acid. He was wearing spectacles, so he was fortunate, he didn't get any in his eyes. The electrical spark must have ignited hydrogen gas. He didn't do that again! Heh! Heh!
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HerHusband wrote:

Even my nine year old granddaughter knows that.
It was her school science project/presentation last December:
http://home.comcast.net/%7Ejwisnia18/temp/birdwire.jpg
That's what you learn early when your dad and hisdad are both EEs. <G>
Jeff
--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
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