The best socket locks, compared.
Top pick: Knightsbridge CU9LOCKN Best value: PlugMinder 38 mm cover – About £18.99 against the same shared review block, when the plug fits 38 mm. The cheaper key-lock socket is a different job and a sample of three. Updated October 2026.
A socket lock stops someone switching, unplugging, or using a UK 13 A point unless they have a key, a tool, or a padlock. Most homes want a cover over a plug that must stay connected. A key-switched socket is a different job, for a shared point that must stay off. A maintenance lockout uses a padlock and a tag, and it does not leave the appliance powered. Judge by that job, then measure from the wall to the furthest point of the plug. The key or tool has to be in the box, and the listing should be Type G to BS 1363. UK sockets are already shuttered, so a plug-in blank is not a lock. The [socket lock buying guide](/hub/sockets-and-extension-leads/socket-lock/sub/socket-lock-buying-guide) separates a cover, a key socket, and a lockout before you choose a depth. Loosen the faceplate screws only after the circuit is proved dead. In England, a like-for-like replacement outside a bath or shower zone is non-notifiable, while a new circuit is notifiable.
A socket lock stops someone switching, unplugging, or using a UK 13 A point unless they have a key, a tool, or a padlock. Most homes want a cover over a plug that must stay connected.
22 products checked · 62 hrs invested · +21,400 readers
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Personal buying guide
Question 1 of 2
What must the lock do?
The Knightsbridge CU9LOCKN is a 13 A double-pole key-lock socket with a neon and one Type G outlet, at about £13.88. The listing line is 5.0 from 3 reviews, and the saved listing holds two UK texts, so that star line is a very small sample. One reviewer says it is just the job and that directions would help a less experienced fitter, and the review title says to get professional help if you are in doubt. The other says the switch works really well and that a 35 mm back box is required. The Amazon listing itself does not state back-box depth. The maker’s datasheet says thermoset resin, names BS 1363-2 and IP20, and asks for a 35 mm box, while the Amazon material line says Metal. The bullets describe a key that locks the socket on or off, with two keys, and a plate that projects 7 mm. They do not describe a cover over a plug. It is the row when you are replacing the outlet so it can be locked off, not when a fridge plug must stay in.
Pros
Cons
Best for: A corridor or shared point where you will replace the socket and lock it on or off.
Less suitable: Keeping a telecare unit or fridge plug in place, or a fit you cannot prove dead before the old socket comes off.
Specifications
Common questions
Does the CU9LOCKN lock a plug in place?
The bullets describe a key lock on or off and two keys. They do not describe a cover over a plug. The listing states one power outlet. It replaces the socket rather than clamping over an existing plate.
What back box do the CU9LOCKN reviews mention?
One UK review says a 35 mm back box is required. The Amazon listing itself does not state back-box depth. The maker’s datasheet asks for a 35 mm box.
What does the CU9LOCKN listing say it is made of?
The Amazon material line says Metal. Colour is white. A bullet says the plate projects 7 mm and claims anti-microbial properties. The maker’s datasheet says thermoset resin, so the two sources disagree.
The Warmhm cover is about £10.49, with a listing line of 4.8 from 7 reviews and three UK texts in the saved listing. Included components name the cover and the keys. The title says it fits UK and US standards and gives a 5.89 by 4.32 inch footprint, but there is no Type G line and no gang, so a British double plate is not shown. Installation type is screw-in, while one UK review describes a self-adhesive pad fitted in under two minutes and says they had expected to fit it behind the socket. That review used it so an elderly couple could not turn off essential equipment, and another buyer used it for a person with dementia to secure switches. None of the three texts records a breakage. A splash-proof claim names kitchens and bathrooms, and the listing has no IP code. It is a cheap keyed box with a short positive sample, and the fit on a UK plate is still unproven in the attributes.
Pros
Cons
Best for: A plate you have already matched to the stated footprint, where you want keys over the switches.
Less suitable: A proven Type G double, a stated plug depth, or a bathroom zone.
Specifications
Common questions
Are keys in the Warmhm box?
Included Components says plug socket covers and keys. The listing question about whether it comes with a lock has no separate answer.
How does the Warmhm listing say it is fitted?
Installation type is screw-in. One UK review says a self-adhesive pad went on in under two minutes and that they had expected to fit it behind the socket. Those two accounts do not match.
Does the Warmhm listing prove a British double plate?
The title says it fits UK and US standards and gives a 5.89 by 4.32 inch footprint. There is no Type G line and no gang. Match the plate yourself before you treat it as a UK double.
The PlugMinder PMDBLWW80 is the white double cover titled 80 mm deep, at about £21.99, with Type G printed on the amazon.co.uk listing. The star line is 4.6 from 43, and that review text is the same block as on the 38 mm listing, so the 43 is one sample. Reviewers describe loosening the faceplate screws, sliding the plate behind, and retightening in a few minutes, then leaving a telecare unit, fish tank, microwave, or charger in place. The bullets include two tools, a window that shows green when unlocked and red when locked, a cable hook, and a UL94-V0 claim. The same shared reviews call the plastic brittle or obviously 3D-printed, and say some moulded plugs only fit if the bottom of the cover is cut. One comment in the block is about a 58 mm order, so it is not evidence that every 80 mm unit was the one being described. It is the top pick here when you have measured a deep plug from the wall.
Pros
Cons
Best for: A double UK socket where a deep plug or plug-top adapter must stay connected, after you have measured about 80 mm from the wall.
Less suitable: A shallow everyday plug you would rather cover at 38 mm, a socket you need locked off, or a maintenance lockout.
Specifications
Common questions
How does the 80 mm PlugMinder cover lock?
The listing says two supplied tools and a window that shows green when unlocked and red when locked.
How is the 80 mm PlugMinder cover fitted?
The listing says loosen the existing socket screws, slide the baseplate behind, and retighten. It states 1 mm wall clearance and no exposure to wiring. It is not adhesive. Prove the circuit dead before the faceplate screws are loosened.
What depth is this PlugMinder listing?
The title says white, 80 mm deep. The same title names 28 mm, 38 mm, 58 mm and 80 mm as other depths. One review in the shared text describes a 58 mm order, so that comment is not proof about every 80 mm unit.
This is the PlugMinder double titled 38 mm deep, model PMDBLWW38, at about £18.99. The listing line is also 4.6 from 43, and the UK review text matches the 80 mm listing, so those two counts are copies of one block. The bullets still describe two tools, a red/green window, a hinged cover, a cable hook, and a fit behind the faceplate screws with a claimed 1 mm wall clearance. There is no Type G line in the attribute table, and the question about fitting all UK sockets is unanswered. Praise in the shared block is the same screw fit and the same uses, including dementia and chargers that had been taken. The criticisms travel with that block: brittle or 3D-printed plastic, a cheap look, and moulded plugs that miss the cable exit. A reviewer who ordered 58 mm said a longer internet plug would not sit inside, which matters if you have not measured. It is the best value in this set when a standard plug really is within 38 mm of the wall.
Pros
Cons
Best for: A double plate and a plug that projects no more than about 38 mm from the wall surface.
Less suitable: Plug-top power bricks, a lead you have measured past 38 mm, or a buy where the attributes must say Type G.
Specifications
Common questions
Does the 38 mm listing say it fits every UK socket?
The listing asks whether it fits all UK sockets and does not answer that question. The title calls this the 38 mm deep double cover. Type G is not an attribute on this listing.
How does the 38 mm PlugMinder cover lock?
The bullets say two supplied tools and a window that shows green when unlocked and red when locked. A cable hook is also named.
Are the 43 reviews only about the 38 mm cover?
The review text is the same block as on the 80 mm listing. One review in that block says the buyer ordered 58 mm. The listing line still reads 4.6 from 43. Count the sample once.
The Marhynchus listing is an industrial socket lockout kit at about £12.88, with 40 mm inside diameter in the title, polypropylene in a bullet, and a size of 13 by 11 by 5 cm at 27 g. The listing line is 1.9 out of 5 from 2 reviews, and the saved listing has no review text, so the low score has no written reason. Bullets describe isolation during maintenance on small and medium industrial sockets, which is a lockout job, not a cover that keeps a household plug powered. Type G is not stated. The title says kit, but included components are blank and the question about whether a lock is included is unanswered, so a padlock in the box is not shown. Waterproofing is claimed with no rating. The rank line sits in Lockout and Tagout Devices. Use it only if the connector you are isolating is about 40 mm across, which this listing does not prove for a UK 13 A plug.
Pros
Cons
Best for: A maintenance lockout where you have checked the connector against a 40 mm inside diameter and you can supply a padlock if the kit does not include one.
Less suitable: A UK 13 A cover, a fridge that must stay on, or any buy that needs written reviews.
Specifications
Common questions
Is the Marhynchus listing a UK 13 A socket cover?
The title is an industrial socket lock device and lockout tagout kit with 40 mm inside diameter. Type G is not stated. The Best Sellers Rank sits in Lockout and Tagout Devices. It is not scored here as a BS 1363 cover.
Does the Marhynchus listing say a padlock is included?
The listing asks whether it comes with a lock and does not answer. Included components are blank. The title says kit, which does not show a padlock in the box.
What size and rating does the Marhynchus listing give?
Dimensions are 13 by 11 by 5 cm and weight is 27 g. A bullet says polypropylene. The listing line is 1.9 out of 5 from 2 reviews, with no review text.
The Sewroro listing is a white plastic cover at about £9.89, sized 15 by 11 by 5 cm and 170 g, first available on 6 August 2026. The title says it is lockable and waterproof, with keys, and it names bathrooms, bedrooms, and kitchens. The saved listing has no Customer Reviews line and no review text, so there is no star score to use. Keys appear in the title, while included components say to see the package. Bullets claim both a flush in-wall fit and wall or floor mounting, and they claim damp or outdoor use without an IP code. There is no Type G line and no gang. Nothing in the listing says the cover closes over a UK 13 A plug that stays powered. At this price it is the cheapest row, and it is also the row with nothing you can check against a British socket.
Pros
Cons
Best for: Only a purchase where you can confirm the pattern from somewhere other than this listing.
Less suitable: Any UK 13 A socket you need to lock using this listing on its own.
Specifications
Common questions
Is a UK 13 A pattern stated for the Sewroro cover?
No. The title is a lockable waterproof outlet cover with keys. Bullets describe a flush in-wall cover and also wall or floor mounting. Gang and Type G are not stated. Do not treat this listing on its own as a UK 13 A socket lock.
What size and weight are listed for the Sewroro cover?
Product dimensions are 15 by 11 by 5 cm and item weight is 170 g. Colour is white. That size is the listed product size, not a stated plug depth from the wall.
Is there a review score for the Sewroro cover?
The saved listing has no Customer Reviews line and no review text. First available date is 6 August 2026. There is no star score to quote.
Six amazon.co.uk listings were scored on 21 October 2026. Weights sum to 100: Amazon evidence 30, listing fit for the job the title claims 35, review outcome 20, shelf value 15. Stars and review counts are the figures on those listings. The two cover listings share one 4.6 from 43 review block, counted once. A very small sample, or a missing rating, is deducted inside Amazon evidence. A title that says UK and US, or a 40 mm industrial inside diameter, is not scored as a proven Type G 13 A cover. There was no lab test.
Amazon evidence
30%Stars and review count on the amazon.co.uk listing, out of 30. A sample of three, or no Customer Reviews line, loses points here. The shared 4.6 from 43 on the two cover listings is one sample.
Listing fit
35%Whether the listing matches the job in the title, out of 35. A cover that keeps a plug in, a key-lock outlet, and a maintenance lockout are different jobs. Type G, gang, and a stated depth add fit. UK and US, or a 40 mm inside diameter, is not scored as a proven 13 A cover.
Review outcome
20%What the saved UK review texts actually report, out of 20. A screw fit and a plug left in score here. Brittle plastic, a cut cable exit, and a missing written review pull the score down.
Shelf value
15%GBP on amazon.co.uk on 21 October 2026, out of 15. A lower price scores higher only when the plug fits the stated depth. A cheaper key-lock socket is a different job and does not take the value award.
The checks run in this order: the job, then pattern and depth, then whether a key or tool is actually supplied. The table is the six stored amazon.co.uk listings from 21 October 2026. None of these products was lab-tested for this page, and none is described as the safest.
A socket lock stops someone switching, unplugging, or using a UK 13 A point without a key, a tool, or a padlock. It is not a plug-in blank. BS 1363 sockets are already shuttered. The IET says a pin travels about 9.6 mm before it reaches live parts, and dummy protectors often have the wrong pin size. BEAMA’s paper of 5 June 2017 advises against those inserts. Electrical Safety First says shutters are the designed protection and that blanks do not repair a bad installation.
BS 1363 sockets are shuttered. The IET, BEAMA and Electrical Safety First advise against dummy plugs and say blanks do not improve on those shutters. A pin insert is not a socket lock.
Measure from the wall to the furthest point of the plug or the cable bend. Many ordinary plugs need about 38 mm. A plug-top brick often needs 58 or 80 mm. That is a rule of thumb. A moulded lead that misses the exit will not sit in a shallow cover.
HSE HSG85 says tape on a breaker is not isolation and points to a lockout so a withdrawn plug cannot be replaced. A cover that keeps a fridge powered is a different device. Do not add the two PlugMinder review counts. The text is one block.
A cover closes over a plug that must stay in. A key-lock socket replaces the outlet so it can be locked on or off. A lockout, with a padlock and a tag, is for maintenance. Electricity at Work Regulations 1989, regulation 12, separates switching off from isolation. HSE HSG85 says tape on a breaker is not isolation. A cover that leaves the appliance powered is not that lock-off. UK points are Type G to BS 1363. In this set the 80 mm PlugMinder listing prints Type G. The 38 mm listing does not.
A key or a tool should be in the box, with the spare stored away from the person you are locking out. Both PlugMinder bullets name two tools. The Knightsbridge bullets name two keys. The Warmhm included line names keys. The Sewroro title names keys, and the included line says to see the package. The Marhynchus question about a padlock is unanswered. Fit the clamp-on cover behind the faceplate screws only after the circuit is proved dead. Replacing a socket is wiring work.
Three typical situations, each with a recommendation from this comparison.
You need a cover over a plug that stands well off the wall, such as a telecare unit or a plug-top charger. The PlugMinder 80 mm cover is the top pick at about £21.99, with 4.6 from 43 reviews. That review block is shared with the 38 mm listing. The same texts call the plastic brittle.
You have measured the plug and it projects no more than about 38 mm from the wall. The PlugMinder 38 mm cover is the best value at about £18.99. The star line is the same shared 4.6 from 43. Type G is not an attribute on this listing.
You will replace the socket so a corridor or shared point can be locked on or off. The Knightsbridge CU9LOCKN is about £13.88, with one Type G outlet and 5.0 from 3 reviews. It does not hold a plug inside a cover. One review names a 35 mm back box.
The top pick is the PlugMinder 80 mm cover at about £21.99. Type G is printed, the title depth is 80 mm, and the listing line is 4.6 from 43 reviews. That review text is the same block as on the 38 mm listing, so the 43 is one sample. Reviews describe a screw fit and also brittle plastic. The best value is the PlugMinder 38 mm cover at about £18.99, when the plug is within that depth. The Knightsbridge CU9LOCKN is cheaper at about £13.88, but it is a different job and the sample is 3 reviews, so it does not take the value award.
PlugMinder 38 mm cover
About £18.99 against the same shared review block, when the plug fits 38 mm. The cheaper key-lock socket is a different job and a sample of three.
Editorial
Peter F. is the editor for DIY & tools at productscompared.co.uk. Comparisons in this category are checked against amazon.co.uk listings, review evidence and public UK sources.
Guides on what to look for, how to use a product, and common mistakes.
Sources taken from the research digest. Listings were scored on 21 October 2026. This page did not run a lab test.
This article contains affiliate links. If you buy through these links we may earn a small commission, at no extra cost to you. Prices, stars and review counts come from stored amazon.co.uk listings. We did not run a lab test.
