Each wire must connect to its appropriate terminal: Live wires (red or brown) connect to the MCB's live terminal. In this video, we'll walk you through the process of wiring a home distribution box with a detailed connection diagram. What is Distribution Board? Distribution board. Connecting a distribution box involves several steps to ensure proper electrical flow. It serves as a central hub for distributing electricity throughout a building, ensuring that power is delivered safely and efficiently to all the required locations. It includes isolator, RCCB (Residual current circuit breaker) or RCD (Residual-current device) devices, protective fuses or MCB's (Miniature Circuit Breaker).