Henry Adams provided the electrical engineering services for the arc flash study supporting the Veterans Administration Regional Office in Philadelphia, PA. The scope of the power system study includes short circuit analysis, protective device coordination study, voltage and arc flash hazard analysis, as well as metering ten transfer switches and providing load analysis.

The electrical distribution system was surveyed by Henry Adams in order to obtain actual field data required for the modeling of the system. As expected, some equipment data was not available and certain assumptions had to be made. Additionally, record drawings and original building drawings were reviewed.

The purpose of the short circuit calculations was to determine available short circuit current levels throughout the electrical distribution system under various operating conditions. The results of these calculations are used to confirm the short-circuit rating of switchgear and panelboards, and to aid in coordinating protective devices.

The protective device coordination study examines the ratings and settings of the existing overcurrent protective devices and identifies those that are currently not properly coordinated. In a well selectively coordinated system, the protective device closest to the fault will interrupt the circuit; thereby minimizing the disruption of electrical service. In low voltage systems, selective coordination is not always achievable due to fixed trip ratings on smaller molded case circuit breakers.

The arc flash hazard analysis determined the incident energy released by an arcing fault at the location of each device in the electrical distribution system. In addition, an arc flash boundary is defined at the distance where a person is expected to receive a second degree burn when exposed to an arcing fault.

Additional Information:

Location	Philadelphia, PA
Owner	General Services Administration

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