Open door arc flash calculations related to closed-door applications

NFPA 70E defines Incident Energy Analysis as “A component of an arc flash hazard analysis used to predict the incident energy of an arc flash for a specified set of conditions.” Conditions presently specified are for hazards that exist when energized electrical conductors or circuit parts are exposed. From a letter of the law perspective, address of closed door Arc Flash hazards requires either the use of a calculation for other than specified conditions or use of equipment for a purpose for which it lacks certification. Practically, combining information from existing calculations with knowledge of existing equipment certification testing can improve understanding of closed door hazards. As a starting point, calculated calories per centimeter squared are translated into equivalent force. Similar conversions are applied to energies of standard device functions such as interruption of available fault currents. Estimated forces are then compared to present enclosure certifications to produce expected closed door hazards based on present incident energy analysis techniques.