Independent comparisons. We may earn from shop links. More info

How to fit a lockable socket cover

Updated: 23 October 2026

You are about to loosen the screws on a UK socket so a lockable socket cover can sit behind the faceplate. The plate still has to move, and that is enough reason to make the circuit dead first. This page is that sequence for a clamp-on cover, and the point where you stop and call an electrician. The product table is the [socket lock comparison](/hub/sockets-and-extension-leads/socket-lock). We used the listings, a Reece Safety sheet for the isolate step, Approved Document P for England, and HSE HSG85, on 21 October 2026. We did not fit a cover in a test house. A qualifying purchase can earn a commission at no extra cost to you.

You are about to loosen the screws on a UK socket so a lockable socket cover can sit behind the faceplate. The plate still has to move, and that is enough reason to make the circuit dead first.

Our top picks

Knightsbridge Knightsbridge CU9LOCKN

Best overall

Knightsbridge Knightsbridge CU9LOCKN
6.7/10about £13.88
View offer
PlugMinder PlugMinder 80 mm cover

Rank 2

PlugMinder PlugMinder 80 mm cover
8.6/10about £21.99
View offer
PlugMinder PlugMinder 38 mm cover

Best value

PlugMinder PlugMinder 38 mm cover
8.2/10about £18.99
View offer
On this page
  1. 1.What you are fitting
  2. 2.Make the circuit dead first
  3. 3.The screw sequence, then the stop
  4. 4.A new key-lock socket is a different fit

What you are fitting

You are fitting a baseplate behind the screws of a socket already on the wall. PlugMinder's bullets say loosen the screws, slide the baseplate behind, and retighten. Shared reviews say it is not adhesive. After it is locked the plug is still powered. Two tools turn a window from green to red. That is a barrier around a live plug, not a maintenance lockout. Do not mix methods. Warmhm says Screw-In, and one UK review describes a self-adhesive pad. A cover that keeps the plug in is the wrong device if the plug must stay out while you work. HSE HSG85, paragraph 49, says a withdrawn plug must not go back in during the work. Tape on a breaker is not that method. A closed cover with the plug still live is not that method either.

Make the circuit dead first

PlugMinder's range page says the baseplate goes behind the faceplate and the socket is not removed. One Socketsafe page claims you need not disconnect the mains on a sound BS socket. Do not copy that claim. The screws still loosen and the plate still eases forward. Reece Safety's sheet for its own SSC1 and DSC1 covers says switch off at the mains first. Use that only for the isolate step. Prove the circuit dead before the faceplate moves. Electricity at Work Regulations 1989, regulation 12, is the isolation duty where those rules apply. If you cannot prove the circuit dead, you do not start. A bathroom zone is a stop. Warmhm and Sewroro name bathrooms, and neither listing has an IP code. CU9LOCKN's maker sheet says IP20, dry indoor use.
Knightsbridge Knightsbridge CU9LOCKN

Testsieger

Knightsbridge Knightsbridge CU9LOCKN
6.7/10about £13.88
View offer

The screw sequence, then the stop

With the circuit proved dead, loosen the faceplate screws until the plate eases forward. Reece's own sheet says about 5 mm and says not to remove the screws fully. PlugMinder does not give that figure. Slide the base behind, square the plate, and retighten. Put the plug in, close the cover, and lock it until the window shows locked. Keep the spare tool with you, not beside the socket. Stop if the plate will not ease forward, if the socket is damaged, or if you are in a bathroom zone. If a moulded plug will not pass the exit, measure again on the buying guide instead of trimming plastic. In England, Approved Document P (2013) treats replacement and maintenance as not notifiable. A new circuit, or work in a bath or shower special location, is notifiable. Scotland, Wales, and Northern Ireland publish their own rules. Notifiable or not, you still isolate.

A new key-lock socket is a different fit

Knightsbridge CU9LOCKN replaces the outlet. It is not a plate you slide behind screws you already have. The Amazon listing is one 13 A Type G socket, double pole, with two keys. It does not print a back-box depth. One UK review says 35 mm is required, and the maker datasheet says the same. If the box is shallower, or you cannot prove the circuit dead, do not start. Like-for-like replacement outside a special location is non-notifiable in England under Approved Document P (2013). That is not a promise that you should do it. The connector attribute says Plug-In, which fights the title of a wall socket. That line is not a fitting method. If you cannot prove the circuit dead and finish the swap, the electrician is the fit.

Common questions

Do I switch the breaker off before I loosen the faceplate?
Yes. Prove the circuit dead before the plate moves, even when a bullet says the wiring is not exposed and a review says the job took a few minutes. A claim on another brand's page that you need not disconnect the mains is not the instruction here. If you cannot prove the circuit dead, leave the screws alone.
When does fitting a cover become a job for an electrician?
When the plate will not ease forward, when the socket is damaged, when you are in a bathroom zone, when the conductors are not as a simple plate should leave them, or when the job has become a new socket or a new circuit. CU9LOCKN is already that second job. A review on it tells a less experienced fitter to get help if in doubt.
How is a key-lock socket different to fit?
A cover uses the screws that are already there, once the circuit is dead. CU9LOCKN replaces the outlet. You need a back box the review and the maker sheet both put at 35 mm, which Amazon does not state. You are changing a wired accessory, not clipping a guard over a plug. If you cannot prove the circuit dead, you do not begin.
Can I use the cover as a lockout while I work on the appliance?
No. The cover is meant to keep a plug in and powered. HSE guidance on lock-off is the other way round: a withdrawn plug must not go back in during the work, and tape on a breaker is not enough. Use a proper lockout for that job. Do not shut a live plug inside a cover and call it isolation.
What if the plate will not ease forward?
Stop. Do not lever it, and do not keep unscrewing until cables come with it. A stuck plate, a scorched socket, or a box you do not recognise is the electrician's job. Reviews that mention a few easy minutes are about plates that already moved.

Related pages

Socket lock vs plug-in covers

Socket lock

Best socket lock UK: one cover, one key-lock socket

Lockable socket cover: which kind, then plug depth

Socket lock dementia: keeping the essential plug in

Sources

Sources taken from the research digest. Listings were scored on 21 October 2026. This page did not run a lab test.

  1. Plugs and Sockets etc. (Safety) Regulations 1994 (retrieved 21.10.2026)
  2. IET Wiring Matters, socket-outlet protectors (February 2020) (retrieved 21.10.2026)
  3. BEAMA position paper on socket outlet covers (5 June 2017) (retrieved 21.10.2026)
  4. Electrical Safety First — socket covers (retrieved 21.10.2026)
  5. Electricity at Work Regulations 1989, regulation 12 (retrieved 21.10.2026)
  6. HSE HSG85 (retrieved 21.10.2026)
  7. Approved Document P (England, 2013) (retrieved 21.10.2026)
  8. CU9LOCKN datasheet — ML Accessories (retrieved 21.10.2026)