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Surge-protected extension lead buying guide in the UK

Updated: 23 October 2026

You have one wall socket left, and every result mentions joules, USB or eight sockets. A surge protected extension lead is still a single UK 13 A trailing socket. It can absorb some voltage spikes, and it does not add current. This guide is from the Products Compared editorial team on 20 October 2026. It uses the twelve amazon.co.uk listings in the [extension lead with surge protector comparison](/hub/sockets-and-extension-leads/extension-lead-with-surge-protector), priced from about £8.70 to £29.99. It is not a lab test. A qualifying purchase can earn a commission at no extra cost to you.

You have one wall socket left, and every result mentions joules, USB or eight sockets. A surge protected extension lead is still a single UK 13 A trailing socket.

Our top picks

Masterplug Masterplug SWSRG4210N

Best overall

Masterplug Masterplug SWSRG4210N
9.0/10about £9.50
View offer
Masterplug Masterplug SRG4210N

Best value

Masterplug Masterplug SRG4210N
8.3/10about £8.70
View offer
DEWENWILS DEWENWILS 6-way 3 m

Alternative

DEWENWILS DEWENWILS 6-way 3 m
8.6/10about £16.99
View offer
On this page
  1. 1.The plug, before the joule number
  2. 2.Joules, an indicator, and the 13 A ceiling
  3. 3.Switches, cable, and tower or strip
  4. 4.What this set still does not state

The plug, before the joule number

Regulation 35 of the Electrical Equipment (Safety) Regulations 2016 expects domestic equipment with a flex to reach the wall through a correctly fitted BS 1363 plug, or a conversion plug with a BS 1362 fuse. BEAMA’s checklist adds that a strip with surge parts or USB should meet BS 1363-2. On amazon.co.uk that shows up as a Type G cell, a fuse rating, and sometimes a BS 1363-2 line in the bullets. Several rows agree on Type G and still show Type B in a second field. The switched Masterplug four-way and six-way list both, and the Belkin four-way does the same. The Belkin six-way lists Type B in both plug fields, with no 13 A line in the listing. HANYCONY lists only Type B. Treat those rows as unresolved until the plug in the box is a UK three-pin. The DEWENWILS six-way is the opposite case: both plug fields say Type G.

Joules, an indicator, and the 13 A ceiling

Electrical Safety First is clear that surge protection is not overload protection. A joule figure, where the seller states one, describes energy the surge parts are rated to absorb, not extra amperes. Masterplug’s sheet for the SRG family lists 370 J, says a higher rating absorbs more energy, and says the device is not a lightning arrester. Philex’s instruction for SLx surge leads says that if the surge LED is out and the sockets are still live, replace the lead. The 13 A limit travels with the plug fuse. Watt lines in this set, from 2,990 W to 3,250 W, are that same plug at different nominal voltages. Eight sockets still share one fuse. What each listing prints is on the joule figure guide.
Masterplug Masterplug SWSRG4210N

Testsieger

Masterplug Masterplug SWSRG4210N
9.0/10about £9.50
View offer

Switches, cable, and tower or strip

Five Masterplug bars here are 2 m strips at 370 J, from about £8.70 unswitched to about £12.49 with a switch on each socket. DEWENWILS is 3 m at about £16.99, with four switches claimed on six sockets and 270 J only in a bullet. HAFINO at about £20.62 and Anker at about £29.99 are towers with USB. Reviews say switched Masterplug LEDs stay bright in a bedroom. HAFINO’s switches control groups. Anker has one switch for the tower. BEAMA expects 1.25 mm² or 1.5 mm² flex above 2 m, but conductor size is n/a on every row here. Daily limits are on how to use a surge-protected extension lead.

What this set still does not state

HANYCONY claims surge protection and prints no joules. Both Belkin amazon.co.uk rows show 6,912 reviews and the same opening titles, so treat that count as one shared sample. Warranty wording is a sentence, not a test score. Masterplug pays up to £1,000 for connected equipment for three years, UK only, and says the unit is not a lightning arrester and that daisy-chaining voids cover. Belkin’s UK page for the four-outlet model uses a £20,000 sentence. The six-way bullet mentions £30,000. Neither figure tells you the plug in the box.

Common questions

What should I check before the joule number?
Confirm a Type G plug, a BS 1362 fuse, and BS 1363-2 where the seller claims it. Then look for a stated joule figure and a surge indicator. Socket count, USB and tower shape come after those checks.
What if the table says Type G and Type B?
Treat it as unresolved until you see the plug. The listing disagrees with itself. Rows with Type B only, the Belkin six-way and HANYCONY in this set, should not be bought on faith for a UK wall socket. Rows that print both types need the same pause.
Is a surge label the same as overload protection?
No. Surge parts address spikes. The fuse still limits total load. London Fire Brigade says not to put a kettle, a toaster and a microwave on the same extension, and that rule does not relax because the bar says surge on the box.
When do I want a switch on each socket?
When you want to leave plugs in and stop a heat tool without reaching behind the unit. Pay for a switched Masterplug model if that habit matters. Accept the bright LEDs, or choose an unswitched bar if the lead sits in a dark bedroom.
What cable length is actually in this set?
Most Masterplug and Belkin bars are 2 m. DEWENWILS is 3 m. HAFINO and HANYCONY state 1.8 m in their fields. Measure your run before you pay for length you will coil under the desk.
When should I leave this category for a plain lead?
When you do not need a stated surge figure or indicator, or when unresolved plug fields and missing BS 1363 lines outweigh the joule headline. A plain switched or unswitched 13 A lead may be simpler if spikes are already handled at the consumer unit.

Related pages

Best extension lead with surge protector

Extension lead with surge protector

How to use a surge-protected extension lead safely

What joules mean on a surge-protected extension lead

Surge-protected extension lead for a home TV and PC

Sources

Sources taken from the research digest. Shelf prices, stars and review counts are the amazon.co.uk figures in the stored listings. This page did not run a lab test.

  1. Electrical Equipment (Safety) Regulations 2016, regulation 35 (retrieved 22.10.2026)
  2. Electrical Safety First — extension leads, cable reels and block adaptors (retrieved 22.10.2026)
  3. IET — Surge protective devices (retrieved 22.10.2026)
  4. London Fire Brigade — cables, fuses and leads (retrieved 22.10.2026)
  5. OPSS — ETSC extension lead with USB ports, 2105-0126 (retrieved 22.10.2026)
  6. Masterplug — surge warranty (retrieved 22.10.2026)
  7. Belkin UK — BSV400af2M four-outlet surge strip (retrieved 22.10.2026)
  8. BEAMA — extension lead safety check-list (retrieved 22.10.2026)