Jody Wrote:

> [ Mike Ames reported a story to me where he was swimming in
> [ a swimming pool with a broken light fixture.  As he swam
> [ towards the broken fixture (which he was unaware of) he
> [ began to feel the shock get gradually stronger.  He turned
> [ around and swam the other way and lived to tell about it.
> [ My recommendation:  Don't try this at home!    Jody

This is why GFIs are now also required on all swimming pool light
fixtures.

I remember a similar experience when I was a kid.  The pool light was
cracked and full of water.  One might logically think that since the
pool light fixture is immersed in a giant water bath, in cement, in
the ground, in addition to the grounded conductor (white wire) being
in close proximity, that you wouldn't get a tingle as you approached
the fixture.

The reason you do get a tingle is because, obviously the white wire is
not the least resistant path to the current flow in this scenario.
Let's see, you have an, at least, 15 amp circuit at 120 volts, wide
open to various grounds.  That sucker can put out the equivalent of
1800+ watts in all directions.  This is probably going to be quite a
bit over the comfortable current carrying capacity of the small white
wire that was designed to carry maybe 600 watts.  If it's a 20 amp
circuit, we're talking 2400+ watts flooding into the pool!  Much
more than a portable heater!  It's going to be radiating out toward
the pool drain and to the filter inlet about 1/2 to 3/4 the length of
the pool from the light fixture.  Also the filter return pipe and
maybe a water filler pipe, which could be located nearer the opposite
end from the light fixture...

OK, the swimmer is getting tingled as he gets closer to the light
fixture even though he is immersed in, and part of the conductor.
The reason the swimmer gets zapped is because, the human body being
about as salty as sea water, is much more conductive of the current
that the surrounding water.  Pool water does have a lot of dissolved
salts, but the salinity doesn't approach that of a human body.

As the swimmer approaches the light fixture, even though the current
is flowing unimpeded all around him, it still will want to flow through
the path of least resistance, which in this case in the swimmer.
Because there is a higher potential in front of the swimmer than
behind, some of the current is going to go through him enough to be
felt.

"Grounded conductor" means the white wire.  It is a grounded current
carrying conductor.  It is grounded at the Main switch box only.
Carries current to complete a circuit in a two wire system.

A "ground wire" or "grounding wire" is always green or plain copper
wire.  Normally does not carry current, except when it's doing its
job of protecting a system.  That current flow will hopefully be of a
very short duration, a GFI and/or a breaker will be tripped, before
there is any damage done.

Tom Lear
San Francisco, Ca.