The best advice? Simply avoid them.
And, no matter what, don't become electricity's "path to ground," warned Mike Glowacki of Public Service Electric and Gas, or PSE&G, New Jersey's largest power company.
He told The Early Show consumer correspondent Susan Koeppen Thursday that the first thing you should do is be aware of power lines overhead.
"The lines are up there, and you don't realize they're up there," he explained. "After a while, it's like being in the driveway: Your car's just there. You know it's there. The wires, you don't realize they're there.
"When you're doing work around your house, such as cleaning gutters, washing windows, or painting, and you take a ladder out, stick it up in the air, on the side of the house, that's when you realize they're there.
"If you lose control of a ladder, let the ladder go. If you hold on to the ladder, you will become the path to ground. And that's what you do not wanna be, the path to ground."
A colleague of Glowacki's demonstrated what could happen if you do become the path to ground. He held a ladder up to a 7,600-volt power line. A blue arc of electricity seemed to pop out of the ladder.
"That's electricity making the path to the ground," Glowacki explained. "You do not want to become the path to ground. That will shock you, hurt you, do some damage to you."
Another potential danger: kids playing with balloons or kites or other devices that can go up in the air.
Again, a Glowacki co-worker showed what could happen, letting a Mylar
balloon float into a power line. It caught fire immediately.
"If you have a rope to (the balloon) or a string on it, you'll become the path to ground with that," Glowacki emphasized. "Again, you do not want to become the path to ground. You want to watch where you put those things. Be aware of the lines above you."