According to The National Institute for Occupational Safety and Health (NIOSH), electrocution results when a human is exposed to a lethal amount of electrical energy. To determine how contact with an electrical source occurs, characteristics of the electrical source before the time of the incident must be evaluated (pre-event). For death to occur, the human body must become part of an active electrical circuit having a current capable of overstimulating the nervous system or causing damage to internal organs.
Based on the National Traumatic Occupational Fatalities (NTOF)’s, surveillance data for the period from 1980 through 1992, 5,348 workers died from contact with electrical energy (an average of 411 deaths per year). Electrocutions were the fifth leading cause of death, accounting for 7% of all workplace fatalities. In the 12-year period from 1982 through 1994, NIOSH investigated 224 electrocution incidents which resulted in 244 worker fatalities.
The extent of injuries received depends on the current’s magnitude (measured in Amps), the pathway of the current through the body, and the duration of current flow through the body (event). The resulting damage to the human body and the emergency medical treatment ultimately determine the outcome of the energy exchange (post-event).
Electrical injuries may occur in various ways: direct contact with electrical energy, injuries that occur when electricity arcs (an arc is a flow of electrons through a gas, such as air) to a victim at ground potential (supplying an alternative path to ground), flash burns from the heat generated by an electrical arc, and flame burns from the ignition of clothing or other combustible, nonelectrical materials.
Direct contact and arcing injuries produce similar effects. Burns at the point of contact with electrical energy can be caused by arcing to the skin, heating at the point of contact by a high resistance contact, or higher voltage currents. Contact with a source of electrical energy can cause external as well as internal burns. Exposure to higher voltages will normally result in burns at the sites where the electrical current enters and exits the human body. High voltage contact burns may display only small superficial injury; however, the danger of these deep burns destroying tissue subcutaneously exists.8 Additionally, internal blood vessels may clot, nerves in the area of the contact point may be damaged, and muscle contractions may cause skeletal fractures either directly or in association with falls from elevation.9 It is also possible to have a low-voltage electrocution without visible marks to the body of the victim.
The Occupational Safety and Health Administration (OSHA) addresses electrical safety in Subpart S 29 CFR 1910.302 through 1910.399 of the General Industry Safety and Health Standards. The standards contain requirements that apply to all electrical installations and utilization equipment, regardless of when they were designed or installed. Additionally, the National Electrical Code (NEC) and the National Electrical Safety Code (NESC) comprehensively address electrical safety regulations. The purpose of the NEC is the practical safeguarding of persons and property from hazards arising from the use of electricity.