A complete UK guide to wiring a domestic lighting circuit from the consumer unit — cable sizing, MCB selection, loop-in method, junction box method, switch drops, two-way switching, and how many lights a circuit can supply. This project involves installing a new branch circuit, which consists of a dedicated circuit breaker, the cable run, and the final connection at the switch. Every light fitting in your home is part of a lighting circuit. It shows the wiring layout and the components involved, including the switches, cables, and grounding wires. In this guide, we will walk you through the basics of. Wiring a Distribution Board is vital in any electrical installation.