I do believe you're right bruce, it's amazing what you can see when you know what your looking at isn't it.

That was an amazing louggie from the grassy knoll.

He's also soaked from mid-shirt down, to improve conductivity. But that brings up the question -- how do you install a light fixture over a filled pool?

Drain the pool?

Cordless

There's also the distinct possibility that the power was cut.

That doesn't matter when you're using an extension cord that may drape into the water. UT is right - cordless is the way to go here. At most, he'd lose a decent drill that way, possibly a screwdriver depending on what level of cordless we're talking about.

Not to the drill ...

Hire an illegal alien, they're cheap and disposable.;)
If the cord hits the water probably nothing would happen. If the plug between the drill cord and extension cord hits it would probably short out and blow the fuse/breaker. Neither should pose a threat to the guy on the ladder. But if the drill shorts out the guy is now the path to ground. Bzzt, zap, fizzle he's done.

But he does have his safety goggles on.

(He does, check it!)

And lots of refreshments.