That on at least was an electrical worker, and the reason can be put on inadequate safety procedures or training, the 13 year old probably was more similar to OP case, an innocent person not doing any electrical work happened to get into the wrong place at the wrong time. If comments from news media in OP case are correct, it was not a motor that shorted out that was the real problem, it was likely improper equipment grounding or poor selection of overcurrent protection. Failure of the motor can be expected to happen at some time, and that is why we install equipment grounding and overcurrent protection.
We have no idea what actually happend there. Yes the newpaper said the motor shorted, but I doubt that there had been any type of investigation at the time the story was written that would tell us the actual mode of failure. I also have not seen motor maintenance instructions that specified any type of maintenance that would let you predict and prevent a winding failure.
Keeping a machine clean is one of the most important maintenance instruction. Dust accumulation in the windings of the motor can lead to its failure in the long run.
There are any number of possible root causes that could have energized the water. Any failure of the insulation of any ungrounded part of the electrical system that supplies the motor as well as a failure of the motor itself could cause this porblem. A code compliant installation would prevent most of these possible causes from actually energizing the water.
Given the information in the newpaper report it would be very unlikely that the motor would be of "open" construction that would permit dirt and dust to accumulate on the windings.
Failure of insulation or a failure of motor itself happens due to lack of proper maintenance and improper maintenance is the root cause.
May be or may not be. But it may be kept in mind that keeping the machine clean is one of the most important maintanance activities.
The kind of maintenance that would predict an insulation failure, just is not very commonly done.
Could be, but again, not something that is commonly done.
I will agree that fresh water is less conductive than salt water, I will not agree that it is non conductive. Pure water with no dissolved minerals of any kind is non conductive, it is very difficult if not impossible to find pure water outside of water that man has purified. Even rain water picks up things while falling, and picks up even more once it hits the ground, although it very well may be more pure than ground water.
