Quote:
Originally Posted by
cppond 
This issue came up on another thread. I don't know that it occured in the thread where this came up, but it is good for people to know about. I am no expert, but I will tell you what I know.
There does not have to be electricity in the pond for this to occur as water is a great conducter and even wet concrete can theoretically carry the stray voltage. "Stray voltage" is a voltage which develops on the grounded neutral of either the pond wiring or even the utility distribution system. The most common cause of stray voltage is high resistance on the neutral wire caused by loose or corroded connections or undersized wires. Some times the wrong type of electrical equipment is used during installation, some times it's corrosive switches and connectors, or frayed insulation, faulty equipment, poorly grounded systems, overloaded power lines and being at the end of an electrical service line.
It can be a bunch of different things and the severity of the problem can vary depending on how much equipment is being run at any given time.
A couple of weekends ago a neighbor of mine discovered a similar problem around his swimming pool. In one area of concrete when it gets wet you get a little tingling. When the area that got wet dripped water into the pool, the voltage could theoretically carry into the pool for a moment. The "shock" was not sufficient to hurt people, but stray voltage has been known to kill fish and apparently has been an ongoing issue in cow milking facilities.
That's all I know. I am not saying it happened in any particular instance, but it's something of which we should all be aware.