Arc Flash Calculations for Exposures to DC Systems

Abstract

Electrical systems with AC voltage have been shown to exhibit arc flash incident energy during faults. Are there arc flash hazards related to dc systems, such as battery banks for UPS or drives, or dc buses used in chemical processes? Methods are available to estimate arc flash energy of ac exposures, but not dc. This paper will show the basic equations for maximum power from a dc arc and the resulting estimated arc flash incident energy. Research is required to find accurate values, but until research is completed, these equations can help the engineer provide a preliminary estimate of the thermal energy values for applying protective clothing for these exposures.