Dorchester Central dispatched Station 1 units for a commercial building fire. Chief 1 arrived on location with nothing evident after his 360 and established command. Engine 1-4 arrived on location and stretched 200' of attack line to side alpha but upon further investigation found an electrical outlet short. Units Engine 1-3, Utility 1-1, & Engine 16-1 arrived on location to assist, with the situation under control command was terminated and all units went in service without incident.