Wiring Direction: Wiring between the main circuit breaker and each branch circuit breaker in the box generally goes on the left, and the wiring out of the distribution box generally goes on the right. Follow this guide for a clear and safe connection process: Before starting, always ensure the main power is turned off to avoid electrical shock. Fix the box securely to the wall, ensuring it's at an accessible. Learn how to wire a distribution box step by step! This video shows real on-site footage of electrical installation, demonstrating safe and standardized wiring methods used by professionals. It takes the incoming power and safely distributes it to different circuits throughout your building. Wire color: The neutral wire is blue, and the color of the phase wire (A phase is yellow, B phase is green, and C phase is red).