Transformer room fire tests

A series of transformer room fire tests are reported to demonstate the shock hazard present when automatic sprinklers operate over energized electrical equipment. Fire protection was provided by standard 0.5 inch pendent automatic sprinklers temperature rated at 135 F and installed to give approximately 150 sq ft per head coverage. A 480 v dry transformer was used in the room to provide a three phase, four wire distribution system. It is shown that the induced currents in the test room during the various tests are relatively small and pose no appreciable personnel shock hazard.