chapter  13
19 Pages

Electrical Drawings

WithJoseph E. Fleckenstein

There are many variations in the formats of electrical drawings. This chapter introduces samples of the types of drawings used in the electrical industry. To illustrate the principles involved, relatively simple examples are cited. By means of established notations and symbols, the one-line diagram describes the fundamentals of an electrical system. In a sense, the diagram is the starting point for any new or proposed system. Three-line diagrams are prepared not so much to show the concept of a system. Rather, three-line drawings show more details than what is shown on the associated one-line drawing. Logic diagrams present the basic criteria, expressed with a unique set of symbols, for the requirements of a control system. Ladder diagrams are a type of electrical schematic drawing that represent the logic of an industrial control system with physical components. Electrical cable drawings show the sizes as well as the origins and destinations of the cables of an installation.