In this article electrical engineer, Les Winter, P.E., provides an introduction to the most common causes of electrical shock injuries that occur in domestic, commercial, industrial, and construction settings.
Electrical shock injuries typically occur for one of two reasons: faulty electrical insulation, or working on live equipment.
Electrical Shocks in Residential & Institutional Settings
In homes, schools, hotels and the like, the electrical system is designed to prevent contact between live wires and people by surrounding them with insulation. As these wires age, the insulation turns brittle and its ability to perform its function becomes degraded. Where the wiring is subject to flexing, as in extension cords, loose wall receptacles and loose wall switches, the insulation can break off, leaving the conductors bare.
Contact with the conductor, or with metal which is in contact with the conductor can cause dangerous shocks. Improperly installed or inadequately maintained grounding can also be a cause. The conductor may arc to nearby metal, causing high temperatures and fires. These dangerous conditions are typically the result of inadequate inspection and maintenance of the building’s electrical system.
Electrical Shocks in Commercial Settings
In commercial settings, a frequent cause of injury to building workers occurs while removing and replacing failed energized lighting fixture ballasts. These components are frequently powered by 277 Volt circuits. Contact with live components at such an elevated voltage can result in severe shock injuries and then, typically, a fall from a ladder. Workers suffer these injuries because the circuits they are working on are not de-energized. The reasons often given for this dangerous practice include the building owner’s intention to not inconvenience office workers, to not schedule the work to take place during evening or weekend (overtime) hours, or a failure to consider the hazard level the worker will be exposed to.
The standard of the electrical installation and maintenance industry is to de-energize circuits before allowing personnel to work on them. The experience and training of the worker is not a reliable substitute for de-energization.
Electrical Shocks on Construction Sites
In construction settings, workers are frequently sent to perform demolition and installation work in areas where the electrical system is not yet removed or not yet completely installed. Under these conditions, live wiring, which is not enclosed in walls or electrical conduits, is vulnerable to contact by tools or by the workers themselves. Shocks result.
On properly run construction sites, wires which are subject to damage or contact by workers are either de-energized or relocated or both.
INVESTIGATING ELECTRICAL SHOCK INJURIES
The electrical engineers at Robson Forensic regularly investigate electrical shock injuries and electrocutions to determine their cause. These investigations typically include an evaluation for the presence of defects, the adequacy of warnings and instructions, and user actions.
Les is a testifying expert who specializes in electrical construction site injuries. His forensic expert experience spans more than 20 years. During this time, he has investigated hundreds of electrical fires and shocks. His professional electrical background includes more than 40 years experience in electrical construction, design and job-site supervision in New York City and North Jersey. Les is a Professional Engineer, licensed in New York and New Jersey. He is a graduate of the City College of New York.
Several members of the electrical engineering practice group regularly investigate electrical shock incidents. Please contact Robson Forensic to discuss your case and determine which of our experts is best qualified to assist with the specific issues in your case.