How to replace a light switch
Updated: October 2026
You are standing at a single plate in a UK hallway, the rocker is cracked or yellowed, and the job looks like two screws. It is still a lighting circuit until you have proved the conductors dead. This page on how to replace a light switch is for a like-for-like swap of one existing plate, not for a new circuit and not for a full stair diagram. The plates in the [light switch comparison](/hub/electrical-equipment/light-switch) are the ones whose reviews keep mentioning short screws. If you cannot prove the circuit dead, you do not take the plate off.
You are standing at a single plate in a UK hallway, the rocker is cracked or yellowed, and the job looks like two screws. It is still a lighting circuit until you have proved the conductors dead.
You are standing at a single plate in a UK hallway, the rocker is cracked or yellowed, and the job looks like two screws. It is still a lighting circuit until you have proved the conductors dead. This page on how to replace a light switch is for a like-for-like swap of one existing plate, not for a new circuit and not for a full stair diagram. The plates in the light switch comparison are the ones whose reviews keep mentioning short screws. If you cannot prove the circuit dead, you do not take the plate off.
Our top picks
| Badge | Product | Ways | Plate | Fixings | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  British General BG NBN12 black nickel | 2-way | Metal | Matching screws stated | 9.4 | about £5.99 | View offer |
 Knightsbridge Knightsbridge CU1000 1-way white | 1-way | Urea | Screws and caps | 9.2 | about £3.99 | View offer | |
| Best value |  Knightsbridge Knightsbridge CU2000 curved white | 2-way | Plastic | Screws and caps | 9.2 | about £3.00 | View offer |
On this page
Replacing a plate is not the same job as adding a circuit
In England, Approved Document P (2013) treats like-for-like replacement of a light switch as work you do not have to notify a building control body about. The notifiable list is a new circuit, a replacement consumer unit, or an addition in a special location around a bath, shower, pool or sauna. Swapping a tired plate on an existing lighting circuit, in an ordinary room, sits outside that list. That document is England’s. Wales, Scotland and Northern Ireland are not covered by it. An ordinary 230 V plate does not belong in zones 0, 1 and 2. If the plate is beside a bath or shower and you are not sure which zone it sits in, that is a stop.
Prove the conductors dead before they are touched
Electrical Safety First and HSE HSG85 describe the same order. You identify the circuit, switch it off, lock it off, and prove the conductors dead with a suitable voltage tester. Prove that tester on a known live source before the test, and prove it again afterwards. A light that happens to be off is not a test. The device you secure is the breaker or fuse for that lighting way, not the wall switch. The wall switch only breaks the switched live. If you cannot identify which breaker feeds the plate, you stop.
Copy the old terminals, then deal with the screws
Photograph the old plate before the wires come out, close enough that the terminal marks and the core colours are readable. A 2-way plate used on a one-way circuit leaves the spare terminal empty. A blue core, or an older black core, at a UK switch is often the switched live, not a neutral. If L2 is new to you, the terminal names sit on the 1 way vs 2 way light switch page. Reviews in this set mention short faceplate screws on the plastic plates and on the metal plates. Keep the old screws until the new ones reach the box thread. Only the chrome listing states a minimum box depth, 16 mm.
Four reasons to stop
Stop if you wanted a metal plate and there is no green-and-yellow protective conductor in the cable. Plastic is the limit. Do not fit brass, chrome, black nickel or matt black on a cable that has never had an earth. Whether a metal face is allowed is on the metal or plastic light switch page. Stop if the conductors do not match a simple one-way or two-way photo, including an intermediate with four terminals. Stop if the plate is in a bathroom zone, or you are adding a point rather than replacing one. Stop if you cannot prove the circuit dead, including a tester you have not proved or a neon screwdriver offered as a substitute. Call a qualified electrician for any of those four cases.
Common questions
Do I have to notify building control to replace a switch?
In England, like-for-like replacement of an existing switch is not notifiable under Approved Document P. A new circuit, a replacement consumer unit, or work in a bath, shower, pool or sauna location is different. The work must still be safe and within your competence. Wales, Scotland and Northern Ireland do not use that English document as their rulebook. Notification is not a certificate from this site, and it is not a reason to skip isolation.
How do I know the circuit is dead?
Identify the lighting circuit, switch it off, and secure it so another person cannot restore it. Prove a suitable voltage tester on a known source or proving unit, test the conductors you will touch, then prove the tester again. That is the order in the Electrical Safety First isolation guide and in HSE HSG85. A lamp that is off, or a neon screwdriver, is not that test. If you cannot identify the breaker, you stop.
What should I photograph before the wires come out?
The terminal marks and the colour of every core, close enough to read COM, L1 or L2 if they are printed. Include the earth, or the empty space where an earth would be. The photo is what you copy onto the new plate. It is also what you show an electrician if the cores turn out not to be a simple pair. Take it only after the circuit is proved dead.
The new screws do not reach. What is going on?
Short faceplate screws are a repeated review on the plastic and metal plates in this comparison, not a fault of one brand. The old screws often still reach a recessed box when the new ones do not. Only the chrome plate states a 16 mm minimum box. Longer M3.5 screws and extension studs exist for a deep box. They must not be driven into a cable.
There is no green-and-yellow wire. Can I continue?
You can continue only with a plastic or urea plate, and only if the rest of the swap is a simple like-for-like on a circuit you have proved dead. You do not fit a metal plate. Older lighting circuits, often pre-1966, were installed without a CPC. Leaving the metal plate in the basket is the safe branch. Calling an electrician is the branch if you still want that finish.
Related pages
Sources
Public UK sources are listed below. Shelf prices and star lines are the amazon.co.uk figures checked on 21 October 2026.
- Approved Document P (2013, England) (retrieved 21 October 2026)
- EN 60669-1:2018 in the legislation.gov.uk record of Decision (EU) 2020/1779 (retrieved 21 October 2026)
- BSI: BS EN 60669-1:2018 scope (retrieved 21 October 2026)
- BEAMA: load ratings for manually operated functional switches (retrieved 21 October 2026)
- IET: Section 701, locations containing a bath or shower (retrieved 21 October 2026)
- NICEIC via Voltimum: wall-mounted light switches (retrieved 21 October 2026)
- NICEIC via Voltimum: lighting circuits without a CPC (retrieved 21 October 2026)
- B&Q: how to replace a light switch (retrieved 21 October 2026)