For some reasons. Just don't plug it on your genitals, otherwise even if you get zapped on the hand (happened to me several times) it hurts a bit, but that's the biggest risk because there's a breaker on the other side of the line and the power will go off quickly. But in general you'll just be turning off the power and you'll be fine. I generally put the wires together just to make sure there's really no power and if there's it makes a spark, then the breaker goes off. The biggest with electricity is to make sure you respect the wires sizes and connections style for the kind of current that will run on the line. 8-gauge for 40A/240v, 12-gauge for 20A/120v, 14-gauge for just a few lights. The biggest pain is making holes in your walls, pulling wires through the beams and patching the walls... That's the hard part!