Overhead power lines, which are located high off the ground for safety, have no insulation and can carry more than 500,000 volts. Substations and transformers contain "live" parts that are dangerous to contact. Underground power lines are well-insulated, but a shovel can damage them and create a shock hazard.
Electricity always seeks the shortest path to the ground. It tries to find a conductor, or something that it can pass through to get to the ground, like metal, wet wood or water. Your body is about 70 percent water, so that makes you a good conductor, too. For example, if you touch an energized bare wire or faulty appliance while your feet are touching the ground, electricity will automatically pass through you to the ground, causing a harmful or even fatal shock.
It doesn't take much to get hurt or killed from even a small amount of electricity. The current from a 7.5 watt Christmas tree bulb can kill you in a fraction of a second if its current passes through your chest. So the best thing you can do is be aware of the dangers of electricity and learn how to avoid them.
When working outdoors, please be aware of the dangers of working near overhead power lines. These power lines are not insulated, and they carry enough energy to cause serious injury or even death. Keep ladders and other equipment at least 10 feet away at all times. If you see a downed line, keep everyone away and call us immediately at our emergency number.
To further ensure your safety, consider all lines "energized" and put an effective ground on all equipment working near overhead electric lines.Read More (PDF)