A1: An electric power distribution line construction drawing, commonly known as a single-line diagram (SLD) or one-line diagram, is a simplified, schematic representation of an electrical distribution system. These blueprints use a single line to represent all phases of a circuit and employ standardized symbols to show the major components. The purpose of these drawings is to provide a clear, easy-to-understand overview of the entire system, detailing the flow of power, the interconnection of equipment, and the locations of key devices such as transformers, circuit breakers, and switches. They are essential for designing, planning, constructing, and maintaining power lines.