Reducing the Arc-Flash Incident Energy in the Secondary Bus of Medium and Low Voltage Substations

For several decades, Occupational Safety and Health Administration (OSHA) has increased its requirements for companies to reduce accidents resulting from electric shock or other injuries resulting from direct or indirect contact with energized conductors in electrical equipment. Users need to refer to the guidelines outlined in the National Fire Protection Association standard NFPA-70E, as well as IEEE Std 1584, to satisfy OSHA requirements. An arc hazard analysis to determine the incident energy of the electrical equipment is a fundamental requirement, to ensure that the proper Personal Protection Equipment (PPE) is available to protect workers against high incident energy. From the arc-flash analysis, many users are discovering higher than acceptable levels of incident energy on the secondary bus of their load center substations. Fortunately, an operation and maintenance arc-flash reduction solution is available that involves designing the protection in the upstream device on the primary side of the MV or LV load center substation.