A study of ARC flash incident energy variations based on MCC unit configuration

There has been significant progress on arc-flash research in recent years, but there has been little focus on how the internal configuration of equipment affects the incident energy released. The relationship between low voltage motor control center (MCC) unit configurations and incident energy exposure resulting from an arc flash is examined in this study. Testing was conducted using actual MCC structures and units. The design of experiment methodology was used to analyze several MCC configuration variables, including unit type, unit size, percent fill of unit, power wire size and length, location of the unit within the structure, and their relationships to incident energy as well as arcing duration and arcing current. The results from 24 arcing tests were analyzed and the magnitude of incident energy measured during the events was observed to be related to the percent fill of components within the units, and properties of interior unit surfaces.