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Back-Feed Near Miss

Our underground crew arrived at a construction site to install new single phase 800 -amp service. Being the crew leader, I went into the typical main switch electrical

room and checked the switch open. Looking over the cabinet, from a wire pulling point of view, everything seemed normal.

On many worksites, there is music playing. For some unknown reason, intuition maybe, I decided to walk around looking and check for a back-feed.  Everything looked normal, except that I noticed there was a cord plugged into the wall behind the boom box.  The drywall installers were mudding their walls, so I kept looking.

I returned to the electrical room knowing that, in this case, the feedback was not from electrical cords running from building to building. Using the voltmeter, I confirmed there was secondary voltage on the load side of the switch. No warning signs, of course!

It was a multi-phase project. They had fed the second building from the first building via the splitter box. It looked innocent and to the site foreman, it was ingenious, since he said it had been done before.  Well, I told him, it was a big problem that presented a large hazard to our crew, the metering crews, any electrical crews that were not aware of it, as well as others on the site. That was when he started to realize a few things.  Just locking off the main switch, to install the new service wire, may have gotten his part of the job complete but it was setting up a trap for others. And it is unlawful.

Follow up, good safety awareness and great habits are extremely important.  

Bruce Masse – Trouble Technician

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