Exposed to the Arc Flash Hazard

It is widely acknowledged that an arc flash hazard may exist when energized conductors are within equipment in an enclosed condition if a person is interacting with the equipment at close proximity in such a manner that could cause an electric arc fault. This paper presents the results of scouting tests of arc flash events within enclosed low-voltage equipment (internal arc faults). This testing was performed to see if the incident energy mitigation efforts of one company were adequate to prevent arc flash exposures to equipment operators should an arc fault occur within the equipment they interact with. Arc faults were initiated within low-voltage disconnect switches, industrial control enclosures, and motor control center (MCC) buckets. Only the possible severity of such events on nearby operators was investigated. No attempt was made to identify the likelihood of such events from operator interaction, nor all of the potential causes of internal arc faults.