According to this article in IPT magazine, recent changes in workplace safety regulations have heightened the awareness of hazards associated with electrical arcs. The hazard level must be quantified and workers properly protected before entering proximity of exposed energized conductors. NFPA 70E provides the guidelines for work involving electrical hazards and the selection of arc-flash protective equipment.
To select the protective gear properly, one must have knowledge of the potential thermal energy of the electric arc. The IEEE standard 1584: “Guide for Performing Arc-Flash Hazard Calculations” has been the de facto standard for calculating the arc energy levels at different points in the electrical power system.
However, NFPA 70E also provides the option of using the HRC task tables for PPE selection. These tables provide predefined levels of PPE, which are based on the available short circuit current and the speed of the overcurrent protective device. Therefore, to apply the tables properly, some degree of electrical calculations must be performed and the tables could be subjected to misuse if they are applied
Click here to read the full article in IPT magazine.
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