Case history: Eliminating multiple sources of error

Electrical incidents are seldom the result of one lapse in judgment, one equipment failure, or one design choice. This is an electrical arcing incident case history that occurred at a leading petrochemical facility and which resulted from a combination of human error, operational procedures which excessively exposed the worker, and design choices made in the interests of economy rather than maximizing protection when developing the system. After this incident, the plant addressed ALL its causes in a multi-faceted solution: The facility engaged outside help to re-engineer the switchgear-contactor bussing arrangement; operating procedures were changed to eliminate the worst arc-flash exposures; custom relaying and sub-feeds were incorporated into present and future designs of this system.