Minimizing burn injury: electric-arc hazard assessment and personnel protection

Significant progress has been made in understanding the arc flash hazard and protecting people. Standard tests have been established to determine the incident energy required to cause ignition of non-FR clothing and evaluate the protective characteristics of FR clothing. One process for selecting FR clothing to protect personnel against arc flash injury has been presented. Protective characteristics for classes of FR clothing and rainwear have been summarized. This performance information is based upon test data produced in a laboratory simulation, not in real-life conditions that may vary. The user is responsible for determining appropriate FR clothing and protective equipment based upon the actual conditions of use and exposure. Incident energy levels produced by three-phase arcs with a 1.25 in electrode gap on a 600 V electrical system with varying bolted fault values have been experimentally determined in a laboratory setting. Algorithms have been developed for predicting incident energy as a function of available bolted fault current, arc duration, and distance from the arc electrodes; and constant incident energy boundary distances.