Can I change a light fitting myself?

This is the most attempted electrical job in Britain and the one with the most near-misses, for one reason: people turn the light switch off and assume the fitting is dead. In a loop-in ceiling rose, the permanent live and the loop terminal remain live with the switch off and the bulb out. Isolating at the board is not caution, it is the difference between safe and not.

Safety

Step by step

1. Confirm the room is ordinary.Not a bathroom or shower room and not outdoors. Both are notifiable special locations requiring a qualified electrician. If the fitting is over a stairwell you cannot reach safely, that is also a stop.
2. Check whether the new fitting needs an earth.A metal fitting requires a circuit protective conductor. Many older lighting circuits do not have one. Establish this before you buy — if there is no earth at the rose, you can only fit a Class II all-insulated fitting there until an electrician provides one.
3. Isolate at the consumer unit and prove dead.Find the lighting MCB, switch it off, lock or tape it, and tell the household. Prove the fitting dead at its terminals with a two-pole approved voltage indicator, proved on a known source before and after. A non-contact pen is a screening tool and does not prove dead.
4. Photograph the existing rose thoroughly before touching a core.This is the single most important step. Photograph which cores are in which terminals, from more than one angle, and count the cables. A loop-in rose typically has three cables and it is not obvious afterwards which was which.
5. Understand the three terminals.A loop-in rose has a loop or line terminal where all the permanent lives are joined and which never goes to the lamp, a switched live terminal fed from the switch which does go to the lamp, and a neutral terminal. The loop terminal is the one that is still live when the switch is off.
6. Label every core before disconnecting.Masking tape flags, written. "Loop", "switched live", "neutral", one per core. Do not trust colour: in old wiring the switched live is black, in newer wiring it is blue, and either may or may not be sleeved brown.
7. Fit a ceiling rose adaptor plate if the new fitting has fewer terminals.Most decorative fittings have only line, neutral and earth. The permanent loop conductors still have to be joined together somewhere safely — either in a maintenance-free connector inside the ceiling void or, better, by leaving the existing rose in place and using a suitable connection plate. Twisting them together and tucking them up is not acceptable.
8. Support the fitting properly.A heavy pendant or chandelier must be fixed to a joist or a proper batten, not to a plasterboard ceiling with the rose screws. Check the weight and the fixing before you commit.
9. Stop if you find any of four things.No earth conductor and a metal fitting; rubber or fabric insulation that crumbles; scorching or a burnt smell at the rose; or a wiring arrangement you cannot make sense of from your photographs. Any one of these and you refit the old fitting or leave the circuit off and call an electrician.
10. Restore and check.Every screw tight, no bare copper outside a terminal, earths sleeved, no core trapped by the cover. Restore the MCB, test the switch, and press the RCD test button to confirm protection is working.

Tips

• Do this in daylight. Working on a ceiling light with the circuit off means no light, and a head torch beats holding a phone in your teeth.
• Take the bulb out before you start. It is the easiest thing to break and the most annoying thing to break above your head.
• If the fitting is an integrated LED unit rather than a bulb holder, the whole fitting is the consumable — when the LEDs fail, the fitting is replaced, not relamped. Bear that in mind when buying.

Common mistakes

• Isolating at the wall switch instead of the consumer unit — A switch normally breaks only the line conductor to the lamp. The permanent live loop at the rose stays live with the switch off, and it is directly under your fingers.
• Not photographing the original wiring — A loop-in rose with three cables has six or more cores. Reassembling from memory is how switched lives end up in loop terminals, which causes anything from a dead light to a permanently on one to a fault.
• Joining the loop conductors with a twist and tape — Every connection must be enclosed, accessible or maintenance-free. A taped twist in a ceiling void is a loose connection waiting to arc where nobody will see it.
• Hanging a heavy fitting from the rose screws in plasterboard — The screws are sized to hold a plastic rose, not four kilos of glass. The failure mode is the fitting coming down and staying connected by its cores.

If it doesn't work

Questions people ask