Everyone makes mistakes. Some are just funnier than others.
Years ago as an electrician for a major school district, I was working on a fire alarm system in an elementary school. While I was on-site, a staff member found me and excitedly said they needed my help — some children were trapped in a bathroom and couldn't get out. Sure enough, the door to a small bathroom on the second floor couldn't be opened by either the children stuck inside or the staff outside. It seems that someone had installed an exhaust fan through the bathroom wall, and it created a negative pressure that prevented the door from being opened. We couldn't locate the distribution panel that served the fan, and turning off circuits didn't help. So we decided to break out the lower panel on the door to relieve the vacuum. As soon as we did, the kids started climbing through the opening, heads and feet all at the same time.
I was called to an automotive repair/body shop to install an outlet for a brand new copier. After scoping out the job, I found a subpanel 10 feet from the office where they wanted the outlet. I thought I'd install some pipe, wire, and the outlet and be out of there no problem. I finished cleaning up, but instead of grabbing my meter to prove my work, I just grabbed the cord and plugged in the machine to check for power. After the smoke cleared, I pulled out my meter and found there was 208V to neutral. It seems the electrician before me had fed the subpanel with the wild leg from the 3-phase, 120/240V delta panel. The only other circuits in the panel were a water heater and welder, so the wild leg had never shown up before. Thinking there was a neutral in the panel, I assumed that both legs were 120V. I hope someday I can meet the other electrician to see if he has an extra $1,300 to pay for that copier.
Minnesota Lake, Minn.
Illustrations by Clint Metcalf