How to hide an extension lead
Updated: 23 October 2026
The lid will not close, or it closes and you cannot see the block again. That is the usual failure when a UK extension goes into a cable tidy box. How to hide an extension lead, here, is a short order of work: measure the block with the plugs in, give every live lead a real exit, leave the cavity so you can look later, and stop if the lid, the smell, or the flex is wrong. The comparison is the [cable box comparison](/hub/diy-supplies/cable-box). Peter F. used the listings and public UK sources, not a lab test. A qualifying purchase can earn a commission at no extra cost to you.
The lid will not close, or it closes and you cannot see the block again. That is the usual failure when a UK extension goes into a cable tidy box.
The lid will not close, or it closes and you cannot see the block again. That is the usual failure when a UK extension goes into a cable tidy box. How to hide an extension lead, here, is a short order of work: measure the block with the plugs in, give every live lead a real exit, leave the cavity so you can look later, and stop if the lid, the smell, or the flex is wrong. The comparison is the cable box comparison. Peter F. used the listings and public UK sources, not a lab test. A qualifying purchase can earn a commission at no extra cost to you.
Our top picks
| Badge | Product | Stated fit | Cable exits | Lid | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  D-Line D-Line cable tidy box, small, black | 4-gang blocks up to 280 mm | 3 | Snap-on lid | 9.5 | about £9.99 | View offer |
| Alternative |  Bearware Bearware cable tidy box | Size not published | n/a | Tight lid, end tabs | 7.5 | about £16.90 | View offer |
| Best value |  GOZOLA GOZOLA rattan cable box, 2-pack | 33 × 15 × 13 cm and 28 × 10 × 10 cm | 4 | Button lid | 7.3 | about £23.99 | View offer |
On this page
Measure the block with the plugs in
Put every plug you will leave in the strip and measure the length and the height. Compare those numbers with a fit the listing prints. The only published internal fit in this set is the D-Line small unit: popular 4-gang blocks up to 280 mm. If the block is already longer than that, a title that says large does not help. Where the listing prints no millimetres, the fit is n/a. Which job to buy is the cable tidy box buying guide.
Route the leads through real openings
The incoming flex needs one opening on a face you use. The appliance leads need the others. An unused hole on the back does not count if your leads leave to the left. D-Line states three exits. GOZOLA states four. Seat the block so it is not hanging on its own flex. The Fire Protection Association says not to hang a block on its cable. A lead pulled tight over the lip is the home version of that fault. Where reviews describe a tight snap lid, as on D-Line and Bearware, do not force a charger through a full slot. Bearware's sample includes a unit that cracked from a cable hole.
Leave the cavity able to breathe and to be checked
Do not pack the cavity. On the D-Line small unit, the UK datasheet says to leave about 45 percent of the internal capacity free for 240 V cables. That figure is D-Line's, not a result for the rattan, wood, or other plastic boxes. UL 94 HB on the same sheet does not mean the shell contains a fire. If the lid presses on the plugs, that cavity is too full. A heater or a kettle goes in a wall socket.
Stop if the lid, the smell, or the flex is wrong
Close the lid only if it closes without crushing a plug. Forcing it is how a tight shell cracks at a cable hole. Unplug and stop if you smell hot plastic or see scorch marks. If you are daisy-chaining, or before you drill a wall, call a registered electrician. One pick per job is the best cable management box page. If the lead still crosses the walkway, the box has not finished the task.
The order, then stop
Measure with the plugs in, give each live lead an opening you actually use, then leave the cavity so the lid is not pressing on the plugs. A close that needs your weight is the wrong combination. A hider does not cover a lead people walk over, and it does not add sockets.
Common questions
How do you measure a UK extension block before it goes in the box?
Fit the plugs you will leave in, then measure the length and the height of the tallest plug. The only internal fit in this set is D-Line's 280 mm for popular 4-gang blocks, in a 325 × 125 × 115 mm shell. If the listing has no millimetres, the fit is n/a on the page until the box is in your hand. Do not invent a length the listing does not print.
Where should the incoming lead and the appliance leads leave the box?
Give the incoming flex one opening on a face you use, and the appliance leads the others. D-Line states three exits and GOZOLA states four. A hole on a face you do not use does not count. Keep the block supported. A flex pulled tight over the lip is the same fault as hanging the block on its cable.
How much empty space should you leave, and whose figure is that?
D-Line's UK datasheet says about 45 percent of that unit's internal capacity should stay free for 240 V cables, with a 60 °C ambient and UL 94 HB on the same sheet. It is not a result for the rattan, wood, or other plastic boxes here. If the lid presses on the plugs, that D-Line cavity is too full. UL 94 HB does not mean the shell contains a fire.
Can you coil a cable reel inside the box?
No. Electrical Safety First and the Fire Protection Association want a reel unwound while it is in use. Keep only a loose loop of spare flex in the hider. Plug heaters and kettles into a wall socket rather than into the hidden strip. A modern lead is usually 13 A, and some older leads are 10 A.
What do you do if the lid will not close?
Remove the plug that is holding it open. On the D-Line small unit that is often a USB charger or a smart plug. On the generic rattan box, reviews include a 4-gang that would not take USB plugs as well. Do not force the lid. If the block is longer than the stated fit, you need a different published size or fewer devices. Bearware's sample includes a shell that cracked from a cable hole.
When is the next step a registered electrician rather than a bigger box?
Call one if you live on daisy-chained leads, if a hot smell remains after you cut the load, if the flex is damaged, or before you drill a wall. Scorch marks and melted insulation mean unplug and stop. Another hider does not add sockets, and the large D-Line 6-gang size is not in this set. A lid is not that job.
Related pages
Sources
Public UK sources and the amazon.co.uk listings compared on this page. Updated 22.10.2026.
- Electrical Safety First, extension leads, cable reels and block adaptors (retrieved 22.10.2026)
- BSI, BS EN 60670-22:2006+A11:2024 (retrieved 22.10.2026)
- D-Line cable tidy unit (retrieved 22.10.2026)
- D-Line cable tidy unit datasheet (retrieved 22.10.2026)
- Fire Protection Association, extension lead briefing (retrieved 22.10.2026)
- HSE, electricity introduction (retrieved 22.10.2026)
- GOV.UK, consumer product safety advice (retrieved 22.10.2026)
- Which?, faulty products and the Consumer Rights Act 2015 (retrieved 22.10.2026)