Take the appropriate rating of MCB and RCCB as per your load requirements. Connect the phase and neutral wires from the input power supply to the input of the Main MCB. Connect the output of the Main MCB to the input of the. 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. Load centers, also known as breaker boxes or distribution boards, are the central hub for distributing electricity throughout a building or home. This article mainly talks about the first one. In this guide, we'll break down everything you need to know to install.