Failures Of Equipment Operating Under Normal Operating Conditions

Informational Note No. 1 for the definition of arc flash hazard in National Fire Protection Association Standard 70E-2015 states "Under normal operating conditions, enclosed energized equipment that has been properly installed and maintained is not likely to pose an arc flash hazard." Table 130.7(C)(15)(A)(a) of the standard states that arc flash PPE is not required for normal operation of a circuit breaker, switch, contactor, or starter if the equipment is properly installed, properly maintained, equipment doors and covers are closed and secured, and there is no evidence of impending failure. This paper will review three electrical equipment failures during substation circuit breaker operations where if personnel had followed the guidelines described above, they could have been seriously injured during these failures due to the arc flash energy released at the time of the fault.