Adding a Light or Switch to an Existing Circuit

Adding a new ceiling light to an existing circuit is one of the most common DIY electrical jobs in the UK — and it's non-notifiable in standard rooms.

Planning the Job

  1. Identify the wiring method — loop-in or junction box (see the identification guide)
  2. Find the last rose on the circuit — or a convenient mid-circuit rose for loop-in
  3. Plan the cable route — ceiling void, surface conduit, or chased in plaster
  4. Isolate the circuit before opening anything

Adding a Light — Loop-In Method

ExistingNew loop cableNewSW

Steps:

  1. At the existing rose, take a new loop cable from the loop-in plate (L, N, E) to the new rose
  2. At the new rose, connect: loop-in L/N/E from the new cable
  3. Run a switch cable from the new rose down to the new switch
  4. Connect the pendant flex

Adding a Switch — Replacing 1-Gang with 2-Gang

To add a second gang (e.g. add a fan switch next to a light switch):

  1. Replace the existing 1-gang switch with a 2-gang
  2. Run a new switch cable from the new gang to the new fitting
  3. The original switch cable connects to gang 1; the new cable to gang 2

Part P Reminder

Adding lights in kitchens, bathrooms, or outdoors is notifiable. In standard rooms it is not.

⚡ Plan your new light on the canvas