A tree trimmer was hired by a contractor to a public electrical utility company to clear branches from power lines. At the time of the clearing, the utility company did not close out the power lines, and the tree trimmer was killed when he made contact with a high voltage line. Counsel for the plaintiff required an expert in electrical utilities to evaluate whether or not the company should have closed out the power lines to accommodate the tree trimmers who were there at the utility company’s request, or if other safety measures should have been recommended.
Question(s) For Expert Witness
- 1. When using sub-contractors for maintenance such as the tree trimming described, do you recommend electrical utility companies close out the power lines in the proximity? Did you do so in your career?
- 2. Generally, what duty does an electrical utility company have to ensure the safety of subcontractors working on or near power lines?
Expert Witness Response E-142720
I am a High Voltage Journeyman Lineman with over 30 years in the industry. I have held a multitude of titles, including High Voltage Power Lineman Instructor, and have worked for various contractors. A high voltage power line should have circuit reclosures. When objects such a tree limbs etc make contact with the line, the circuit will fault. A reclosure allows the circuit to shut off and on three times in 3-5 seconds in an attempt to clear the fault. When the fault cannot be cleared, the circuit is shut down. The reclosure should have been taken out of service prior to trimming the tree. Normally when qualified line workers are on the line, safety measures demand these reclosures be taken out of service to prevent the circuit from turning back on or reenergizing in the event a phase-to-phase or phase-to-ground contact is made. More often than not, tree companies work around energized lines. Some utility companies will have an additional standby lineman on site to watch the workmen as a secondary safety measure. There is also the option to de-energize and ground the circuit. However, depending on the work location and number of customers, de-energizing is not always the utilities first choice.