Arc Flash: Then vs. Now
November 4, 2016 | Gerry Donahue
The electrical professional’s knowledge of arc flash is continually changing. Arc flash was a subject barely discussed 20 years ago in workplace safety. Now it is a critical component for all employees. As it evolves, it is vitally important that the electrical system owner, electrical engineer, and employee be aware of the hazards and methods to effectively evaluate and minimize their risks. There are several key standards and codes that provide a process to evaluate the hazard. The three most important are the NFPA 70 (NEC) which detail the labeling and warning requirements, the NFPA70E which spells out workplace practices involved in arc flash (PPE – hot work permits), and IEEE-1584 which provides one method of calculating the available arc flash energy. These standards are updated every three years. New requirements have been added with each addition, which affect the implementation of the electrical workplace safety plan. Recent changes affect the frequency of labeling, equipment design, and PPE requirements.
In the latest NFPA 70 – 2014 240.87, requirements were added for all electrical switchgear 1200A or greater to have an approved arc flash mitigation method included in the design. Additionally, 110.21 has new labeling requirements. The provision may soon change again in the next code cycle (2017) mandating further information to be included on the label.
NFPA 70E (2015), Standard for Electrical Workplace Safety has numerous changes from the prior version including reclassification of the different PPE categories, energized work permit changes, and additional electrical equipment maintenance requirements.
It is critically important to the wellbeing of all personnel exposed to the risk of arc flash that the updated standards and practice be put into practice. Failure to do so puts all electrical system owners, engineers and employees at risk.