Arc Flash: Not How or Why, but WHEN To Complete an Assessment on an Electrical Distribution System

Arc flash risk assessment on an electrical distribution system is crucial to identify arc flash hazards in the workplace and determine mitigation measures to protect the safety of employees as well as the general public. The National Electric Safety Code (NESC) and the National Fire Protection Act Standard 70E (NFPA 70E) both have guidelines for when and how to complete arc flash risk assessment; however, there are other factors to consider as to when an arc flash assessment should be completed. This paper was completed to offer additional considerations for “when” an arc flash assessment should be completed on an electrical distribution system and how these additional considerations could affect the arc flash calculations.