People Shocked in U.S. Swimming Pool.

If there is current flow in the water between any 2 points, then although the bulk of the current flows the short path, though there is a voltage gradient across all space because of this
click here for pic

All points on any one red line are at the same voltage.  Their spacing is the field strength in volts/meter.

Far enough away the voltage contours get far enough apart (volts per meter gradient low enough) not to trouble the scorers, but it is still there. The field at a distance is in proportion to the initial voltage difference times the spacing of the 2 electrodes.


Generally people are less conductive than salt water ,and more conductive than fresh. 


If you are the high resistance element, you do not want to be in series with a body of conducting water - swimming as it were in between the capacitor plates and  finding most of the volts dropped across you .

If you are the low resistance element then being near one electrode is bad as current that would have flowed in the water around you tends to take the easier path.

In either case you are stuffed if the current is high enough, but the voltage contours look quite different, either bunching towards the body or moving as if trying to avoid it, and it varies if you would stand a better chance moving to be either parallel to or at right angles to the direction of the current flow.



The real secret to an event free life is only to permit 12V transformer isolated lighting for under water illumination that is not  via an air gapped window, and to feed mains to moored boats from individually TT supplies and RCDs.

And in general under water mains voltage lights are just a bad thing in a swimming pool, even if your local rules permit them

If there is current flow in the water between any 2 points, then although the bulk of the current flows the short path, though there is a voltage gradient across all space because of this
click here for pic

All points on any one red line are at the same voltage.  Their spacing is the field strength in volts/meter.

Far enough away the voltage contours get far enough apart (volts per meter gradient low enough) not to trouble the scorers, but it is still there. The field at a distance is in proportion to the initial voltage difference times the spacing of the 2 electrodes.


Generally people are less conductive than salt water ,and more conductive than fresh. 


If you are the high resistance element, you do not want to be in series with a body of conducting water - swimming as it were in between the capacitor plates and  finding most of the volts dropped across you .

If you are the low resistance element then being near one electrode is bad as current that would have flowed in the water around you tends to take the easier path.

In either case you are stuffed if the current is high enough, but the voltage contours look quite different, either bunching towards the body or moving as if trying to avoid it, and it varies if you would stand a better chance moving to be either parallel to or at right angles to the direction of the current flow.



The real secret to an event free life is only to permit 12V transformer isolated lighting for under water illumination that is not  via an air gapped window, and to feed mains to moored boats from individually TT supplies and RCDs.

And in general under water mains voltage lights are just a bad thing in a swimming pool, even if your local rules permit them