When I was a lineman apprentice in Oklahoma, I learned the hard way about underground primary and the capacitance charge it will hold.
We had hooked up a thumper to find a fault and after we found it. We shut down and disconnected the thumper. I started to reach out to touch the exposed line. My foreman told me to get away from there because the line was still hot, due to capacitance charge. I said "it’s just a piece of wire, how can it still be hot? We've got it disconnected at each end!"
The foreman was watching me as he walked over to the truck and was getting a drink of water from the cooler. I looked at him and he was looking at me out of the side of his eye. I thought that he was just playing an apprentice joke on me, so I thought "I'm not buying this one" and I reached out and grabbed the exposed end of the primary. After that, I'm not sure if I got it or it got me but the next thing I remember is being on the other side of the ditch and wondering why a train ran through this ditch and how did I get in front of it! Even my hair hurt!
The foreman just laughed and said "There is a reason why I'm the foreman, you knucklehead. It’s because I know more than you do!" With a great deal of effort, I got my fingers to make the "OK" sign and after that I listened to what the boss said. Good thing I've got a strong heart!
The moral of the story is this: There is no substitute for experience, and if you plan to stay alive, you'd better listen to it!
From an older and wiser man!
From an early Powerlineman.com Forum