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. Hey, in this article we are going to see the Single Phase Distribution Box Wiring Diagram and Connection Procedure. All the electrical sub circuits are originated from a Distribution Board. Main Distribution Board: It is the main circuit breaker panel box connected to the incoming power supply from the secondary of the transformer through an energy meter and an isolator switch.