How to replace a light switch in the UK
Updated: October 2026
A broken rocker looks like a five-minute job: the light is off, the screws are small, and a new white plate is £3.00. Turning the rocker off does not make the cable dead, a blue core in a switch can still be a live strapper, and the screws in the bag are often too short for the box you already have. This page is for a like-for-like swap on an existing circuit, outside a bath or shower zone. Prices sit on the [light switch sockets comparison](/hub/electrical-equipment/light-switch-sockets). This is not a wiring diagram.
A broken rocker looks like a five-minute job: the light is off, the screws are small, and a new white plate is £3.00.
A broken rocker looks like a five-minute job: the light is off, the screws are small, and a new white plate is £3.00. Turning the rocker off does not make the cable dead, a blue core in a switch can still be a live strapper, and the screws in the bag are often too short for the box you already have. This page is for a like-for-like swap on an existing circuit, outside a bath or shower zone. Prices sit on the light switch sockets comparison. This is not a wiring diagram.
Our top picks
| Badge | Product | Switching | Finish | Current | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  BG BG single 2-way switch, antique brass, NAB12 | 2-way | Antique brass | 20 A, 16AX | 9.6 | about £5.79 | View offer |
 Knightsbridge Knightsbridge CU1000 1-gang 1-way switch | 1-way | White | 10 A | 9.4 | about £3.99 | View offer | |
| Best value |  Knightsbridge Knightsbridge CU2000 1-gang 2-way switch | 2-way | White | 10 A | 9.4 | about £3.00 | View offer |
On this page
When a swap is the whole job
A swap is the whole job only when four things are already true. The new plate has the same gang count as the old one. It has the same way: 1-way for one position, 2-way for two positions, intermediate only if the old plate was the middle of three or more. You are not adding a circuit, moving the switch to a new place, or changing a consumer unit. The plate is outside the space around a bath or shower. In England, a straight replacement outside that space is generally not notifiable. It still has to be safe. Scotland does not use England's Part P label.
If any of those four fail, stop. A 13 A socket will not replace a lighting plate because the finish matches. None of these twelve is a pull-cord. Choose the mechanism on the 1-way or 2-way page before the screws come out.
Isolation before the plate comes off
The rocker is a switch, not an isolator. Off at the plate can leave a live strapper in the box, which is why the light going out is not proof. Open the correct breaker at the consumer unit for that lighting circuit, or the main switch if you cannot name the breaker, and make sure it cannot be closed while your hands are in the box. Then prove the tester on a known live source, on the circuit you believe is dead, and on the known live source again. A neon screwdriver is not that test.
Photograph the old plate before any core comes off, including which core sits in COM, L1, and L2 if those labels exist. If you cannot find the breaker or cannot prove the tester, the plate stays on and a competent person takes the job.
Terminals, sleeves, and screws
The photograph is the map. You are copying the old arrangement onto a plate of the same type, not inventing a new one. A blue or black core used as a switch line is sleeved brown at the terminations. That is the identification point in BS 7671 Regulation 514.4.1. An unsleeved blue core in a switch is not a reason to call it neutral and park it in COM. If the new terminals are in a different place from the old switch, stop.
UK faceplate screws are commonly M3.5, and about 25 mm is the ordinary length. That length is not printed on these ASINs. Reviews in this set often find the supplied screws too short. If the new plate is metal, the earth tail is the next decision, on the metal or plastic page, before you close the screws.
When to stop
Stop if there is no earth and the new plate is metal. A metal face needs the protective conductor on the plate and a tail to a metal box. These BG plates are not described as Class II in the capture. That is a competent person's job if you want brass, chrome, steel, or matt black.
Stop if the work is in a bath or shower zone, if you are adding a new circuit, or if the consumer unit itself is being changed. Stop if you cannot prove the circuit dead. After you stop, a later plate choice does not make an unidentified box safe.
Common questions
Is turning the switch off enough?
No. The rocker only opens the switch. A strapper in a 2-way circuit can still be live at the plate, and the lamp being dark does not prove the terminals are dead. Isolate at the consumer unit and prove the circuit with a two-pole tester that you have just proved on a known live source. If you cannot do that, leave the plate on.
What if the blue wire has no brown sleeve?
Treat it as unidentified, not as neutral. In a switch, a blue or black core is often a live strapper and should be sleeved brown at the termination. If the old sleeve has fallen off, your photograph and the other end of the circuit are what tell you which core it is. If you cannot tell, stop. Do not copy a review that put a black core in COM because it looked spare.
The new screws do not reach. What length are UK plates?
The usual thread is M3.5. About 25 mm is the ordinary length for a flush box, and longer screws, in the 35–50 mm range, are what people use when tiles eat the thread. That length is not printed on these amazon listings. Do not keep tightening a screw that never bites.
When is this not a DIY swap in England?
When it is a new circuit, a consumer-unit change, or work in the space around a bath or shower. Electrical Safety First lists those as notifiable. A like-for-like plate outside that space is generally not notifiable, and it is still not DIY if you cannot isolate or the new plate is metal on a cable with no earth. Scotland does not use the Part P label.
What if there is no earth?
Stay with a plastic plate, or have a protective conductor installed before any metal face goes on. A metal plate without a CPC is the wrong finish upgrade. The white plates in this set, including CU2000 at £3.00 and the BG 812 at £4.49, are the rows that do not ask the face itself to be earthed. This page only marks the stop.
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.
- Electrical Safety First: What is notifiable work? (retrieved 21 October 2026)
- IET: BS 7671 18th Edition wiring regulations (retrieved 21 October 2026)
- IET: Section 701, locations containing a bath or shower (retrieved 21 October 2026)
- BEAMA: Load ratings for manually operated functional switches (retrieved 21 October 2026)
- BSI: BS EN 60669-1:2018 scope (retrieved 21 October 2026)
- B&Q: How to replace a light switch (retrieved 21 October 2026)
- Homebuilding: Types of light switches (retrieved 21 October 2026)
- amazon.co.uk listings for these plates (retrieved 21 October 2026)