Why Don't Power Lines Sizzle or Steam Up When Rain Hits Them?
Power lines are specifically designed to carry electricity without heating up so they are not hot enough to turn raindrops into steam.
A single raindrop — or even a lot of raindrops falling closely together — does not provide a continuous path for electricity to travel through, so the electricity just keeps moving through the wires.
However, a continuous stream of water could provide a path for electricity. This is why you should never aim a high-powered water squirter or hose at a power line. Electricity could travel through the water and through you to the ground.
Source: e-SMART