Impact of Arc Flash Events With Outward Convective Flows on Worker Protection Strategies

Recent research into arc flash test configurations suggests that some equipment may have the potential for greater arc flash incident energy than that predicted by IEEE 1584 due to outward convective flows associated with electrode orientation and configuration. This research suggests that lower arcing currents could lead to longer clearing time of protective devices and higher incident energies. Additional research also suggests that flame-resistant materials used in electrical personal protective equipment (PPE) may not provide the same protection levels as predicted by their arc rating when placed within these convective flows. The possible impact on protection requirements, work procedures, and mitigation strategies of these findings is discussed. This paper looks at the impact of adjusting the Cf factor of the IEEE 1584 incident energy equation to accommodate test data from alternate configuration, using lower I_ARC and derating the arc rating of PPE.