Reading Electrical Diagrams, Part 1

Electrical diagrams are drawings in which lines, symbols, and letter and number combinations are used to represent electrical circuits. In some plants, electrical diagrams may also be called prints, or blueprints. No matter what they are called, however, these drawings are valuable tools for anyone involved in making new electrical installations, locating electrical problems, or modifying existing circuits. There are many different types of electrical diagrams. Each type is drawn differently to provide different information. The four types of electrical diagrams covered in this course are block diagrams, single-line diagrams, schematic diagrams, and wiring diagrams.

• Describe the purpose of the American Standard Device Function Numbers Table and the Standard Diagram Abbreviations Table.
• State the purpose of a block diagram and a legend.
• Define the purpose of a single-line diagram.
• Identify a motor circuit and a control circuit on a schematic.