Identifying Which Wiring Method You Have

Before extending or modifying a lighting circuit, you need to know whether it uses loop-in or junction box wiring. The method determines where you connect a new light.

At the Ceiling Rose

Open the rose backplate carefully (with the circuit isolated):

Loop-in (3-plate)Junction box (1-cable)3+ cables enter1 cable enters

Loop-in rose — you'll see multiple cables entering (supply in, supply looping out, switch cable). Three sets of terminals.

Junction box rose — typically only one cable — the pendant feed from the JB. Only the pendant terminals are used.

Cable Count at the Rose

| Cables in rose | Method | |---------------|--------| | 3 or more | Loop-in | | 1 or 2 | Junction box (or end-of-run loop-in) |

Checking for a Junction Box

If you only find one cable at the rose, look in the ceiling void above for a round junction box. It should be accessible. If you find one, you have junction box wiring.

When Adding a New Light

  • Loop-in: Take a new loop from the last rose on the circuit
  • Junction box: Add a new JB adjacent to the existing one, or extend from it

Always isolate the circuit and test before opening any fittings.