The electrical panel box wiring diagram provides a visual representation of the different components and connections within the panel box. It typically includes details such as the circuit breakers, neutral and ground bars, bus bars, and other essential components. A distribution board or distribution box is where the main power supply is distributed to multiple loads. It includes isolator, RCCB (Residual current circuit breaker) or RCD (Residual-current device) devices, protective fuses or MCB's (Miniature Circuit Breaker). A distribution box is the heart of any electrical system. Whether you're an electrician or a DIY enthusiast, this guide will help you understand the basics of home electrical distribution. What is Distribution Board? Distribution board.