This AutoCAD DWG file includes a complete Single Line Diagram (SLD) of a Distribution Board, showing circuit breakers, wiring connections, and load distribution for lighting, power, and mechanical systems. The best distribution system is one that will, cost-effectively and safely, supply adequate electric service to both present and future probable loads—this section is intended to aid in selecting, designing and installing such a system. Today, electrical systems are essential for homes and industries. But what exactly is a power distribution box, and why is it so essential in our daily lives? The DB panel board controls the flow of electricity.