What Happens When the Host Employer Makes a Mistake?: Copyright Material IEEE Paper No. ESW2021-09

Electrical contractors working for host employers often rely on the host employer to shutdown and lock-out/tag-out (LO/TO) electrical equipment and verify the absence of voltage, to create the electrically safe work condition. The host employer would be performing preventative maintenance (PM) on two substations that provide power to a large portion of the facility, requiring a shutdown of production. Meetings had been held with two contractors earlier in the week, contractor A would be working in a motor control center (MCC) and contractor B performing preventative maintenance and substation breaker calibrations on substations SUB-1A & SUB-1B. The shutdown and LO/TO of each breaker would be performed by the host employer's electrician. Contractor A would be working in MCC-1A. Contractor B's work would begin, before contractor A arrived on-site. The day of the shutdown, contractor A's crew reviewed the host employer's shutdown paperwork, signed the paperwork, placed their individual locks on the MCC-1A Lock Box, witnessed the absence of voltage test and completed the work in MCC-1A. Work completed, contractor A's crew and the site electrical lead were walking towards SUB-1A, preparing to unlock the MCC-1A Lock Box. Why did the site electrical lead notice equipment fed from MCC-1A was beginning to power up? What else was wrong or could have gone wrong?