480 Volt Temporary Wiring Causes Near Miss
Contractors were cutting electrical conduits to prep a building for demolition. As the employee began to cut a piece of conduit with a sawzall, he cut into an unmarked live conduit. The conduit was housing temporary wiring used to power an existing lift station after power to the building was isolated. As the employee cut into the temporary wiring, it caused the 480 volt temporary wiring to arc. Upon seeing sparks, the employee immediately stopped cutting and notified his supervision.
All 13,200 volt lines powering the building had been separated several days prior to the incident at the load center by the owner. A separate contract firm then cut visual separations in the high voltage lines at the exterior of the building and also in the substation located in the basement. Temporary wiring powering the lift station was installed in December 2007, with the power being fed from a nearby electrical vault. The temporary wiring was encased in conduit and installed on the north side of the building, where it entered the basement. After entering the basement, the conduit was hung alongside previously existing conduit. However, the newly installed conduit was not marked flagged or painted.
No injuries were reported as a result of this incident.