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  #1  
Old 08-11-03, 07:04 PM
mrwhite
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Current Question

I would like to know , if you are swimming in a pool , treading water ,and an electrical extension cord is dropped into the water, (Live), will the current kill me , shock me or pass right through me? I am not an idiot but am tryin to prove to some friends the truth, thank you for your help in this matter, mr White
 
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Old 08-11-03, 07:06 PM
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Absent any protective circuitry, it may kill you.
 
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Old 08-11-03, 07:45 PM
J
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On a purely theoretical basis, and without any thought that anybody might try anything like this ...

I think as long as you were touching nothing except water, you wouldn't feel a thing. It's the birds on the electrical wire thing.
 
  #4  
Old 08-12-03, 01:28 AM
mcsew2k
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I have first-hand experience with a simular situation. My pool light wiring was defective and I was lucky it only caused a slight tingling shock - not while swimming in the water but only when you are half way in the water and also touching the edge. It was interesting because it was not even noticeable until I bent down to kiss my wife while she was in the water and we both experienced a very interesting sensation in our lips!

I have since disconnected my pool light.

David

PS See my recent post here titled "'Removing defective wiring from conduit".
 
  #5  
Old 08-12-03, 05:34 AM
brickeyee
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You are a better conductor than the pool water due to the higher salt content in your cells. Once your skin is wet it looses a reat deal of resistance. Depending on exactly how the current is flowing you could easily be killed. If you are standing between the hot wire and a return path, the current will prefer your body over the higher impedance water.
When you are immersed in a conductive fluid, the 'bird on a wire model' does not apply.
10 mA through cardiac tissue is a lethal level. The paddles used to shock a heart when the organ is exposed need less than 2 volts to do the job. The higher voltages are only needed to pass through skin from a distance and get the correct level of current in the cardiac tissue.
 
  #6  
Old 08-12-03, 09:52 AM
texassparky
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A defective pool light at an apartment swimming pool caused the death of a child in Dallas a year or two ago. Under just the right circumstances, a 9V battery in a bath tub could even be deadly.
 
  #7  
Old 08-12-03, 10:33 AM
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The bird on a wire theory does not apply because air is an insulator. It might apply if you were swimming in distilled water as that is a very poor conductor. Not sure if it would be considered an insulator.
You could also have a voltage gradient in the pool. Your head could at 100 volts your feet at 20 volts as an example.

The more I think about this the more I know you are not safe. Here is an example. The marine biologists use electrodes to shock fish out the water for testing. The fish are certainly suspended and not touching the anything.
 
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Old 08-12-03, 01:05 PM
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i was just thinking the same thing joed, i dont know how much they use but i know they are only affecting a small area of water when shocking the fish from what i have read. Just makes you think
 
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Old 08-12-03, 01:53 PM
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The birds on the power line are not at ground potential, therefore no power will flow. They are on one wire, so there is no phase difference. You have probably seen the squirrel that tried to step from one conductor to another at the transformer where they come close together. Crispy critter.

In the pool, there is already ground potential because the current is flowing from hot to neutral. You would just be in the loop, so to speak.

GFCIs have a purpose, and this would be it.
 
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Old 08-12-03, 01:57 PM
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As a further note for the bird on a wire, the birds quicly learn to stay off the very high voltage long distance wires (think 500 kV and up). When they try to land, their is enough capacitance to cause a little tingle as they charge up. They learn to stay away.
 
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Old 08-14-03, 07:14 AM
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I would assume the issue of electricuting fish from water is due to the high conductive particulte/ions suspended in that water. Like the other person said. A dionized/RO/distilled water should almost act as an insulator. Peace: e3
 
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Old 08-14-03, 09:04 AM
brickeyee
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De-ionized water is such a good insulator it can be used in flash over tests at 100s of kilovolts for materials research. It is very hard to keep it this way for any length of time. Contaminents from the air get in and the resistance starts to drop.
 
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Old 08-15-03, 10:08 AM
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Its hard to say for sure what would happen, because so many things can vary in the scenario.

One constant is that electricity will always follow the path with least resistance. If you happen to create a path for the electricity to flow from High potential (aka the wires) to Low potential (aka ground) you will get shocked. and unless a breaker blows, it will continue to shock you until you are no longer the path of least resistance.

I would say that chances are good that there will be a better path than you if you are treading water, but I wouldn't touch the metal ladder on the side. It is probaby literally sticking into the ground somewhere.

There probably isn't one great answer to this question. Its kind of a "could this dull knife kill someone" kind of question. There's no real reason to experiment.
 
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Old 08-15-03, 04:52 PM
brickeyee
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With all the salt in your cells you are a much better conductor than fresh water. Salt water is better than you.
 
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Old 08-15-03, 07:08 PM
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Just because your body may be a better conductor than pool water does not mean that you will be injured. Consider when I stand in the center of my family room. My body is also a better conductor than the air in which I am "swimming". If I throw a live extension cord into that same air, I am not injured by it.

I am not saying that this proves I will not be injured. It's just that the issue of whether or not my body is a better conductor than the water is irrelevant.
 
  #16  
Old 08-16-03, 07:51 AM
brickeyee
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No, it is very relevent. You are immersed in a conducting fluid. Current will attempt to take the path of least impedance. The current will preferentially flow through you more than the water.
Even in a wire the current flow is far from uniform. The current in the conductors of a pair of twisted wires is distorted and crowds where the wires are closest. This acts to reduce the impedance of the circuit.
This is part of the reason that being ubder a tree when lightening hits is so dangerous. While the water in the tree makes it a conductor, when the current gets near the ground you are a better conductor. The lightening often exits the tree and jumps to the people.
 
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Old 08-16-03, 09:51 AM
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Yes, I know that current will more readily flow through you than the water around you. The open question is whether or not any current will flow through either one.
 
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Old 08-18-03, 12:16 PM
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I wonder what would happen if I was floating in a tank of liquid mercury while electricity was passing through it. Since mercury is almost as conductive as copper, my guess is that the current would just flow around me since my body is almost an insulator by comparison. Of course, I would probably die from mercury poisoning soon after, but not from electrocution. I would also venture to guess that a person floating in the Dead Sea is less likely to be electrocuted than somebody floating in the ocean or even tap water under similar voltage gradient conditions.

Robert
 
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Old 08-25-03, 11:55 AM
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I think you also have to realize that the current is aiming for a source with different potential or voltage (such as Ground). If you are "floating in a pool" that is all the same potential, there is no need for current to flow through you. The potential of the pool may very well be 120 volts and not shock anybody as long as it is insulated from any other sources/drains of the potential.

Theoretically if you are floating in the pool, and not touching any of the sides or bottom, I think you would be "OK" (as long as you never get out)
 
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Old 08-25-03, 12:08 PM
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If you were floating in the water then would there not be a potential to ground until you actually touched something? At that point you would be in serious trouble but until your body touches something besides the water you should not really feel anything to speak of (at least in theroy and I am not about to test that one)
 
  #21  
Old 08-26-03, 04:27 AM
Paul300
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Originally posted by texassparky
... Under just the right circumstances, a 9V battery in a bath tub could even be deadly.
Interesting! When we were kids we used to stick our tongues to the terminals of used 9 volt batteries (probably had 6 or 7 volts left). Quite a sensation. Not sure why we did it--fun at the time, I guess.

As for the topic, wouldn't a person want GFCI on any electric to the pool? Also, lightning safety brochrues always tell you to get out of the water during lightning storms and often after a heavy lightning storm a lot of dead fish will wash up on shore. No, I don't want to be in the water when a power line drops into the pool.
 
 

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