An arc flash is the result of a rapid release of energy due to an arcing fault. The fault is sustained via highly conductive plasma and the massive discharge (arc blast) vaporizes metal busing and conductors causing an explosive, volumetric increase with an expansion rate up to 67,000:1. The resulting molten debris devastates everything in its path. Temperatures can reach 35,000 degrees Fahrenheit and create debilitating burns within seconds.
An Arc-Flash Hazard Assessment is part of an electrical hazard assessment required by OSHA and NFPA 70E. The requirement has been around for 40 years. In December of 1970, OSHA issued a requirement that the employer “shall furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees.” A final ruling of the Electrical Safety Related Work Practices regulation was issued in August of 1990 requiring that “employees working in areas where there are potential electrical hazards shall be provided with, and shall use, electrical protective equipment that is appropriate for the specific parts of the body to be protected and for the work to be performed.”
To remain in compliance with OSHA requirements, an Arc Flash Analysis should be performed on all Electrical Systems and appropriate labels applied to equipment. This Analysis should be reviewed every 5 years as well as anytime the system is modified.
References: OSHA Standards 29 CFR, Parts 1910 and 1926 / NFPA 70 Article 110.16 / NFPA 70E / IEEE 1584
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