Dropping a live power plug on extension cord into a swimming pool is certainly not a great idea. However I wonder if doing so would kill the swimmer in the pool? I've been searching the internet for some sound explanation, not only yes / no without reasoning.
I'm asking because I was doing some work with power tools around the pool over the weekend and the extension lead cable dropped into the pool. Not the plug, just the cable, so nothing happened. And there were no people in the pool anyway. But it got me thinking what would happened if I immersed the plug?
If it's RCD protected (known as GFCI in the US I think) I assume it would immediately trip because from Live roughly 1/2 of the current would go to Ground and 1/2 to Neutral and RCD would kick in. That should protect the swimmers, right?
However what if there was no RCD / GFCI?
I think the electrical current would again go mostly from Live to Ground + Neutral as these are only millimeters away. Some of it may ground through the concrete and plaster pool floor and walls. Also there may be some water grounding through the pump, filter, salinator, etc.
And what about the swimmer? Would he get electrocuted while swimming? He may be more conductive than the water around (blood being more salty than the pool water), that indeed plays against him. On the other hand he's not grounded as long as he keeps floating.
Does it matter if he touches the walls?
Does it matter how far from the submerged power plug he swims?
I'm not looking for an advice saying that I shouldn't immerse power plug into the pool, I know that :) This is a what if and why that question.