Arc Flash Accidents Explained

By R.W. Hurst, The Electricity Forum

Arc flash accidents occur when a phenomenom known as "arc flash" explodes from energized electrical equipment without warning, injuring anyone in close proximity to the event. Arc Flash happens when the electrical current passes between two energized electrodes through ionized gases and vapors.

The electrical energy supplied to the arc is converted into other forms of explosive energy. This results in incredible heat, explosive noise, expansion of the surrounding atmosphere due to rapid heating, and the subsequent melting/vaporization of arc electrodes and metal components.

What causes arc flash? It occurs when the insulation between the conductive components can no longer withstand the applied voltage.

Arc flash is primarily found in circuits of 208 and higher voltages in commercial and industrial facilities. Protection from arc flash is commonly referred to as a "personnel safety issue".

The number of arc flash accidents that have occurred has prompted many facilities to re-evaluate their electrical safety programs and their lockout procedures in the workplace.

A comprehensive electrical safety program will help protect employees from arc flash accidents and the resulting injuries: shock, burn and other personal injuries associated with arc flash accidents. Often, energized work is being performed without ensuring that an electrically safe work condition exists or that exposed employees or contractors are using the right personnel protective equipment (clothing , face protection, and tools) for the hazards.

What do you do when you can’t turn the power off? Do you expose your employees or contractors to unsafe conditions? Do you expose yourself or your company to liability? What is needed/required when your employees or a contractor work on energized systems?

Fatal Work-Related Electrical Injuries, 1992-2019 Data on fatal electrical injuries is available from the Census of Fatal Occupational Injuries (CFOI), introduced by the Bureau of Labor Statistics in order to create a comprehensive count of fatal occupational injuries in the United States through the use of multiple source documents. CFOI collects information of fatal work injuries in each state from multiple source documents, including death certificates, workers’ compensation records, data from federal agencies, and newspaper reports, and used them to assemble a comprehensive fatal injury profile of workers.

The use of multiple information sources is credited with the creation of a more comprehensive injury database than would be available through a single data source, and CFOI for this reason has been endorsed by both the National Safety Council and the National Center for Health Statistics as the data source for fatal worker injuries. (U.S. Bureau of Labor Statistics) Between 1992 through 2019, CFOI recorded a total of 5587 fatal electrical injuries, an average of 254 fatal electrical injuries each year. Of these injuries, 5527 (99% of the total) were reported to be electrocutions, while less than one percent of the fatalities 12 were due to burns.

The sum of electrocutions and burns is slightly less than the total number of electrical injuries because some information for some injuries may not be reported or because the data does not meet publication criteria. It should be noted that the data for 2019 is preliminary data and the total number of injuries could increase if additional fatalities are reported before the data is finalized.


 

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