Arc flash analysis approaches for medium-voltage distribution

Arc flash is an important consideration for personnel safety. This paper explores available ways to evaluate arc flash severity for primary distribution systems, both in equipment and in open air. Results from staged tests and from utility monitoring data suggest the need to use longer arc lengths than normal as input into open-air arc flash calculations. Results from tests also show how fast arcs can lengthen and evolve to multiple phases, and performance of conductor covers was evaluated.