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Ask an Expert

David A. Dini, P.E.

Research Engineer and Corporate Fellow

What factors are making arc flash a more important issue than previously?

The arc flash hazard is nothing new; it has always been a consequence of working with electricity.  In the U.S., the Occupational Safety and Health Act was enacted by Congress in 1970, which led to the formation of the Occupational Safety and Health Administration (OSHA) a short time later.  To help achieve its responsibilities for fulfilling aspects of this new law relative to workplace electrical safety, OSHA approached the National Fire Protection Association (NFPA) for help in developing a standard for electrical safety in the workplace. This eventually led to NFPA 70E, which was first published in 1979.


Although the NFPA 70E Standard for Electrical Safety in the Workplace originally focused primarily on protection against electric shock hazard, by the 2000 edition, protection against arc flash hazard had been introduced, along with a requirement for using appropriate clothing and other personal protective equipment (PPE) for common tasks where an arc flash could occur.  Around the same time, the Institute of Electrical and Electronics Engineers (IEEE) began conducting research on arc flash and, in 2002, published the first Guide for Performing Arc Flash Hazard Calculations (IEEE1584).  With IEEE1584 and NFPA 70E gaining in popularity throughout the 2000s, employers and workers were becoming much more aware of the arc flash hazard and resulting injuries that could occur if proper precautions and PPE were not used.  Today, many employers train their employees on NFPA 70E, and then provide them with the new lightweight clothing and other protective measures when working in “energized” environments. Good employers now know, more than ever, that protecting their employees from electrical hazards, such an arc flash, is not only a legal requirement but also the right thing to do.

What changes do you foresee over the next 5-10 years that will affect the prevalence and severity of arc flash incidents, either positively or negatively?

One of the basic principles of NFPA 70E is that you should always work “de-energized” (free from electrical connection), and energized work should be the exception. For example, if de-energizing the electrical equipment could create a greater hazard, such as with life support equipment, the standard does permit you to work energized. As more and more employers start using and enforcing NFPA 70E, the prevalence of arc flash incidents should decrease, and we are already starting to see this. Also, when energized work is performed, we are seeing an increasing number of employers providing their employees with the necessary PPE, as required by NFPA 70E, to prevent workers from sustaining second-degree burns should they be subjected to an arc flash incident. Labor statistics show that severe electrical burn injuries are virtually always the result of the proper PPE not being worn or used. The growing popularity of NFPA 70E is definitely having a positive effect on these labor statistics.

What services does UL offer to help companies mitigate the risks of arc flash?

The proper installation, use and maintenance of UL listed electrical equipment is always an important first step in safety, including protecting against the risk of an arc flash. When work must be performed energized, UL certifies several different types of PPE for electrical workers. For example, UL certifies Protective Clothing for Electrical Workers (Guide QGVZ) to the ASTM F1506 standard. This clothing (shirts, pants, overalls, etc.) is rated based on incident energy to protect workers against a second-degree burn from an arc flash. UL also certifies Insulated Tools (Guide QGVT). When an insulated tool is dropped, it is less likely to initiate an arc flash. Arc-Resistant Switchgear is tested and certified by UL to IEEE standards, to protect the operators of this equipment from the effects of an internal arc occurrence. Through UL Knowledge Solutions, we offer special courses with curriculum tailored to NFPA 70E, electrical PPE and ways to mitigate arc flash risks. These are just some of the ways UL’s service offerings can help both employers and employees provide safer working conditions.


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