Electric Shock in Swimming Pool

[nirupshetty]

I had a question in my mind from quite a while regarding electricity and electric shocks in general. I was wondering whether anyone can shed some light to the query:

Q) If a person is swimming in a swimming pool (and not touching any part of the pool concrete or railings) and a live wire falls into the water on the other side of the pool, will the person experience a shock? I am not sure whether it will be a bird on the wire situation. Also if you ask about the voltage ... will it matter whether it is our 110 V or for that matter a distribution line that falls in the other end of the pool.
This question bothers me because recently i heard about some floods in bombay city and roads were flooded with rain water. A lot of people got electrocuted when the distribution line fell into the water. I am not sure whether it was because of the fact that they had their legs on the ground (making them the fault path) or was it just their proximity to the fallen line.

It might be a very fundamental question but this is something for which I have not got a conclusive answer.

Thanks in advance.

Regards,
Nirup Shetty

 

[celtic]

Re: Electric Shock in Swimming Pool

Originally posted by nirupshetty:


Q) If a person is swimming in a swimming pool (and not touching any part of the pool concrete or railings) and a live wire falls into the water on the other side of the pool, will the person experience a shock?

That depends...the distance a person is away from an electrified wire within a pool will yeild the magnatude of shock/electrocution and how the pool was bonded..if at all.

In the illustration above of Mike's (that I graffetied on)...the heavy red line indicates a live wire going into the pool, the heavy black triangle represents the voltage gradient. As a persons distance from the wire increases, the magnatude of potential will decrease...unless it's a straight downward angle. (Also assuming that NO bonding has been performed)

I'd suggest you hear it from Mike:
http://www.mikeholt.com/videodisplaynew.php?pageid=1719
Video links at bottom of his page


Here are some links:
The Danger of Voltage Gradients in the Aquatics Environment

Subject: [Pool Bonding] Re: Grounding of in-ground, liner pool - why?
Mismatching Wet-niche Swimming Pool Luminaires with Forming Shells Can Be a Shocking Combination

 

[charlie b]

Re: Electric Shock in Swimming Pool

From the wording of your question, I think there is a need to clarify one thing. Electrical current is not trying to find its way to planet Earth, as many believe. Therefore, you do not have to be in contact with the Earth, in order to receive a shock.

Another thing that is helpful to know is that dirt is a very good conductor. A downed power line can send current a great distance through the dirt. If you have a pool within the path of that current, then some current will flow through the water. If you are swimming in that pool, you can receive a shock, and it can be fatal. And yes, a 110 volt extension cord that drops into a pool might, under particularly adverse circumstances, cause a fatal shock to a person swimming in the pool. The purpose of that "equipotential bonding grid" that Celtic described is to make the circumstances no longer adverse.

 

[nirupshetty]

Re: Electric Shock in Swimming Pool

Thanks Charlie and Celtic...

Charlie: I understand that current flows when there is a voltage difference. If i curl up my body and float in water won't I be at the same potential.. and hence not be a path for current to flow?

- Nirup

 

[bphgravity]

Re: Electric Shock in Swimming Pool

No, because the water at your feet has a different potential than the water at your head.

 

[charlie b]

Re: Electric Shock in Swimming Pool

I do believe, however, that you are likely to get less of a shock if you curl up, or better yet, get vertical and tread water, than you would if you tried to swim. If you swim, there will be a potential difference from your feet to your head, a distance of perhaps 6 feet. If you tread water, there will be a potential difference between your back and your front, a distance of perhaps 1.5 feet. The shock should be lower in the second case.