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An article in Consulting-Specifying Engineer magazine discusses an approach to preventing arc flash incidents through designing to reduce the incident energy. The article's subtitle is "Understanding electrical distribution equipment and its associated risks can help reduce incident energy levels and save lives."

After an overview introduction to arc flash, and a discussion of the need for an arc flash study and arc flash labeling, the article discusses four methods for reducing incident energy. It concludes with a description of an arc flash incident the author experienced.

One recommendation described in the article is to reduce the seriousness of a potential arc flash by adjusting the settings of solid-state trip-unit circuit breakers. The article states:

"When energized maintenance is required for this equipment or downstream equipment, the energy level and required PPE may be reduced by setting the LTD to 0.5, the STPU to 1.5, and the STD to instantaneous, with the resulting TCC shown in Figure 2 and its corresponding warning label shown in the inset These settings reduce the arcing fault durations (the 85% and 100% fault levels) to 0.02 sec. This means the breaker will clear the fault more quickly. The flash boundary is reduced from 105 in. to 15 in., and the flash hazard has been reduced from 22 Cal/cm2 to 0.86 Cal/cm2."

Read [url='http://www.csemag.com/single-article/preventing-arc-flash-incidents-by-design/9c519a4c62dd83d957e4d1f468d91fc9.html']the article here[/url].





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