Medium-Voltage Arc Flash in Switchgear and Live-Front Transformers

Arc flash on distribution circuits is a safety issue that can impact work practices for line and substation workers. This paper shows test results for arc flash events in medium-voltage switchgear cubicles and live-front transformer enclosures. Both scenarios can result in more incident energy than the prediction of the IEEE 1584-2002. Much higher than expected energies were measured from rack-in style switchgear breaker cubicles due to the orientation of the electrodes. Live-front transformer cubicles showed wide variability that was not directly related to the enclosure size or arc directionality. Unexpectedly high energies were measured in multiple configurations. For selection of the appropriate clothing systems, incident energy multipliers are suggested based on the IEEE 1584-2002.