Junction Box Wiring Method

The junction box method is an alternative to loop-in wiring. A 4-terminal junction box is mounted in the ceiling void; separate cables run to the ceiling rose and the switch.

Circuit Structure

The Four Terminals

| Terminal | Connections | |----------|-------------| | 1 — Mains L | L in (from CU), L to rose, L to switch | | 2 — Mains N | N in (from CU), N to rose | | 3 — Switch | Switch return from switch | | 4 — Earth | All earth conductors |

Advantages and Disadvantages

Advantages:

• Simpler inside the ceiling rose (only the pendant cable connects there)
• Easier to service the rose without disturbing the mains connection

Disadvantages:

• Requires an accessible junction box in the ceiling void
• More cable overall compared to loop-in

Junction Box Accessibility

All junction boxes must be accessible for maintenance. They cannot be buried in plaster or sealed under floorboards. Typically they are mounted to a joist in the ceiling void and accessed from above.