This document provides recommendations for systems engineering@ design@ and integration of electrical power systems at the total ship level from concept design through the establishment of the design baseline prior to detail design. Recommendations for ac power systems@ dc power systems@ emergency power systems@ shore power@ quality of service (QoS)@ power quality and harmonics@ electric propulsion and maneuvering systems@ motors and drives@ thrusters@ and steering systems onboard ships are established by this document. These recommendations reflect present-day technologies@ engineering methods@ and engineering practices. This document is intended to be used in conjunction with the IEEE 45? series of documents. Purpose IEEE Std 45.3? provides a consensus of recommended practices for systems engineering and integration of electrical power systems as applied specifically to ships@ shipboard systems@ and equipment. IEEE Std 45.3 applies primarily to the design of moderately and highly complex vessels. Designers of less complex vessels should selectively apply these recommended practices to address specific systems engineering challenges.