||The specifications of a computer-aided design system are proposed based on the implementation of a prototype subsystem using UNIVAC 1108 and PDP-8 computers. The design system would aid a designer who wished to select and specify electrical fixtures, controls and circuits, and place them in a building whose description is stored in a computer. The proposed Electrical Design System (EDS) is meant to be a subsystem of the Architectural Design System (ADS) . The proposed Electrical Design System is partitioned into four functional areas or modes of operation. They are the lighting mode, the power mode, the service mode, and the circuiting mode. In the first three modes a user of the design system selects a predefined electrical fixture, or specifies a new fixture, appropriate to the mode chosen. He can then add a graphic symbol representing the fixture he selected to a building plan displayed on a computer- graphics console. The fourth mode, circuiting, would provide computer generated circuits containing the fixtures added to the building in the other modes.