I was an apprentice at the time of this incident. Our job was to install a single-phase overhead service into a house. I got the house end connected to the mast and confirmed the meter base open and safe for energizing. Typical install, it seemed.
I was invited up the pole with the journeyman in the bucket. The service was pulled up, on the handline, to be caught off with the jock strap grip. While reaching out to sag the service, the neutral wire began to hum and vibrate. It was splashing out violently when it was touched to the system neutral.
Well, that was the end of that until we figured out what was causing the issue.
Following up, we walked around the house and found an extension cord going to the house out behind this lot. Turns out that the houses behind the new location were fed off from a different substation. When we extended the ground wire, there was a serious difference in potential. Multi grounded neutrals being connected between substations can pose lots of potential and a hazard to linemen.
When you are circle checking for sources of back-feed, it is important to include grounding, not just hot legs.
This was a good learning experience. One I, obviously, never forgot.
Bruce Masse – Trouble Technician