Electrical Distribution System Office buildings usually include a large variety of electrical distribution equipment including transformers, electrical distribution panels, and bus or cable structures. Larger buildings may have large incoming transformers, and newer buildings may have sophisticated power quality control equipment. Electrical power supply equipment is most often damaged through shorting out of wiring or bus structures. A shorted electrical circuit will not only damage the electrical system, but will also cause the electrical service to be interrupted to all areas on the circuit. Electrical insulation failure can lead to the shorting out of wiring, breakers and distribution panels. This can be caused by various situations ranging from abrasion, to moisture contamination or poor maintenance. Poor housekeeping and lack of maintenance may lead to loosening and overheating of connections. Rotating electrical equipment, such as ventilation fan motors, pump motors and elevator motors can be damaged by electrical power disturbances such as power surges. © 2004 The Hartford Steam Boiler Insurance and Inspection Company.     All rights reserved.