The best mains isolation switches, compared.
Top pick: BG Nexus 951 Best value: Knightsbridge CU6300N – Lowest price at this score with a real review count: about £3.74, 4.6 from 361 reviews. Score 92. The specification table does not list a fuse carrier. Updated October 2026.
A mains isolation switch disconnects a UK 230 V supply, or part of it, and is meant to stay off while someone works. Householders meet it beside a boiler, a bathroom fan, outdoor equipment, or the meter. You tell a suitable mains isolation switch by current, poles and the standard on the listing. A fixed appliance is 13 A, or 10 A for a fan. A whole-house switch is 80 A or 100 A. A 16 A rotary is a local box, not a meter switch. Double pole opens live and neutral. A timer fan with a permanent live needs three poles. Four poles are for three-phase. BS 1363-4 is the 13 A fused connection unit. BS EN 60947-3 is off-load isolation, or on-load if it is a switch-disconnector. IP65 is the outdoor claim. IP20 and IP00 are indoor. A seal or a padlock matters where the switch must stay off. The [mains isolation switch buying guide](/hub/electrical-equipment/mains-isolation-switch/sub/mains-isolation-switch-buying-guide) sets that order. Do not pull the cut-out fuse, or open on load a switch with no arc extinguishing.
A mains isolation switch disconnects a UK 230 V supply, or part of it, and is meant to stay off while someone works. Householders meet it beside a boiler, a bathroom fan, outdoor equipment, or the meter.
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Personal buying guide
Question 1 of 2
Which part of the supply are you isolating?
The Nexus 951 is £5.20 and prints 4.8 from seven ratings, the highest star line in the set and the smallest useful sample. The title is a 13 A switched fused connection unit with a square edge and an LED, and a bullet cites BS 1363 Part 4. The saved listing contains one written review, which calls it sturdy and an easy swap. Voltage is not stated in the technical table, and the 25-year warranty is a listing claim. A 4.8 from seven people does not outrank 1,218 ratings on the round-plate 852 when you are choosing on evidence. It is the square-edge twin if that plate shape is what the wall already uses. Leave it if you wanted a review count you can lean on, or a switch for the whole supply.
Pros
Cons
Best for: You want a square-edge 13 A fused spur with an LED and you accept a very small review file.
Less suitable: You want a large UK review count, or any switch above 13 A.
Specifications
Common questions
Is the Nexus 951 a fused spur?
Yes. The title is a 13 A switched fused connection unit with an LED, square edge, and the bullet cites BS 1363 Part 4.
How many reviews are in the file?
The listing shows 4.8 from 7 ratings. The saved listing contains one written review, which calls it sturdy and an easy swap.
Across 1,218 amazon.co.uk ratings the BG Nexus 852 sits at 4.6 and £4.76, the largest review file in this set for a 13 A switched fused connection unit. The listing states double-pole switching, an LED, a round white plate, BS 1363 Part 4 and a 35 mm back box, so you can see whether the spur is on and you know the box depth before you buy. Reviewers use the light as the sign the spur is live. One review reports melting, which is a single fault against a large file rather than a pattern you can count. The 30-year warranty is a listing claim, not something these reviews prove. It isolates a 13 A spur, not a 100 A supply beside the meter. If you want a fused connection unit with a long UK review trail, this is the listing that matches that job, and you still fit the fuse the appliance manual asks for.
Pros
Cons
Best for: You are replacing a 13 A switched fused spur on a boiler or other hardwired appliance and want an LED on a round plate.
Less suitable: You need a 100 A meter switch, an outdoor rotary, or a three-pole fan isolator.
Specifications
Common questions
Does the BG 852 isolate live and neutral?
The listing says double-pole switching and that it isolates a spur from the mains. It is a 13 A fused connection unit, not a 100 A meter switch.
Does it have a power indicator?
Yes. The title and bullets specify an LED, and reviews mention the light as the reason they can see the spur is on.
What back box does it need?
The bullets say a minimum mounting box of 35 mm and that it fits a 35 mm back box.
The BG NBS15-01 is a 10 A three-pole fan isolator at £7.99, with 4.6 from 703 reviews, a brushed-steel plate and IP20. The listing cites BS 60669-1, and the bullet says it can also be used as double pole. That 10 A rating is for a fan unit, not for a 13 A boiler spur or a 100 A meter switch. A moisture gasket is described as protecting the metal edges, which is not an outdoor rating. One reviewer says the fixing screws were too short for the back box. Others praise the brushed-steel look as a replacement for a plastic fan switch. Use it when the fan has a permanent live and you want three poles outside the bathroom zones, and skip it for every other job in this comparison.
Pros
Cons
Best for: You are replacing a bathroom or kitchen fan isolator that needs three poles at 10 A, outside zones 0, 1 and 2.
Less suitable: The load is a 13 A fused spur, an outdoor unit, or the supply at the meter.
Specifications
Common questions
How many poles does the BG fan switch have?
The title and bullet say three-pole, and the bullet adds that it can be used as double pole. It is rated 10 A.
Is it waterproof?
The table says IP20. The bullet mentions a moisture gasket to protect the metal edges, not an outdoor rating.
What fitting complaint comes up?
One reviewer says the fixing screws were too short for the back box. Others praise the brushed-steel look as a replacement for a plastic fan switch.
The Knightsbridge CU6300N is the lowest price here at £3.74, with 4.6 from 361 reviews, a curved white plate and IP20. The title is a 13 A double-pole switch and the listing cites BS 1363-4, but the specification table does not list a fuse carrier. Some reviews talk about a fuse, which does not match that table, so you should not assume a BS 1362 fuse-link is in the plate. Two reviews describe a switch that would not stay off, one of them after six weeks, and another says a neon only faded. The file also has many short positive swaps, which is why the star line stays at 4.6. It is the best value pick if you need a cheap double-pole plate and you have checked that the job does not need a fused spur. It is the wrong plate for a boiler manual that asks for a 3 A fuse in the carrier.
Pros
Cons
Best for: You need a low-cost 13 A double-pole plate and the job does not depend on a fuse in the carrier.
Less suitable: A boiler or other appliance manual asks for a fused spur, or the switch has to live outdoors.
Specifications
Common questions
Is the Knightsbridge CU6300N a fused spur?
The title is a 13 A double-pole switch. The specification table does not list a fuse carrier. Some reviews talk about a fuse, which does not match that table.
Can it go outdoors?
The table says IP20. That is not a weatherproof rating.
What do reviews say goes wrong?
Two reviews describe a switch that would not stay off, one of them after six weeks. Another says a neon only faded. The file also has many short positive swaps.
The WCED WEC440SP is £30.00, with 4.6 from 61 reviews, and it pairs a 100 A isolator with a Type 2 SPD in one enclosure at 230 V AC. The bullet says the arrangement is aimed at BS 7671 surge protection, which is a listing claim, and it also says the switch is sealable. The comparison row lists 4 pole, so you match that count to the supply before you treat it as the ordinary house switch. Reviews say 25 mm² tails are awkward, the lower entry does not line up as well as the top, and the enclosure is tight, so installers feed it from the top. One review says there are no instructions and asks how to reset it after a trip, and the file does not answer that. You pay about £9 more than the WFIS100 for the surge module, and you still need room for the tails. Choose it when a Type 2 SPD beside the meter is the point, and skip it if you only wanted a fused switch with a lid that opens in the OFF position.
Pros
Cons
Best for: You want a 100 A isolator and a Type 2 SPD together, and you can dress 25 mm² tails in from the top.
Less suitable: You only need a fused switch, the tails will not bend into this enclosure, or the job is a 13 A spur.
Specifications
Common questions
Does this enclosure include surge protection?
The title and bullet say a Type 2 SPD with the 100 A isolator. The bullet also says the arrangement is aimed at BS 7671 surge protection. That is a listing claim.
What do installers say about the tails?
Reviews say 25 mm² tails are awkward, the lower entry does not line up as well as the top, and the enclosure is tight, so it is fed from the top.
Are there instructions?
One review says there are no instructions and asks how to reset it after a trip. The saved listing does not answer that.
The WCED WEC4400 is £22.49, with 4.4 from 14 reviews, and the listing describes a 100 A 4-pole isolator with twin screw terminals, a colour-coded handle and sealable lid screws. A bullet says 400 V, and the table also prints 230 V, so the voltage rows conflict. A review says it switches three-phase. IP20 means this enclosure is not the outdoor rotary. BS 7671 is named on the comparison row as a listing reference, not as a certificate in the file. Fourteen reviews is a thin sample next to the 65 on the fused WFIS100. It belongs on a three-phase supply if that is what the board already is, and it is the wrong default for a single-phase house meter.
Pros
Cons
Best for: You are fitting a 100 A isolator on a three-phase supply and you can reconcile the 400 V bullet with the 230 V table line.
Less suitable: A normal single-phase house, an outdoor IP65 job, or a 13 A appliance spur.
Specifications
Common questions
Is the WEC4400 single phase?
The bullet says 400 V and 4 pole. A review says it switches three-phase. The table also prints 230 V, so the voltage rows conflict.
Can the lid be sealed?
The title says sealable lid screws. The IP row says IP20.
The WCED WFIS100 is £21.00, with 4.3 from 65 reviews, and the bullets include an 80 A fuse, a 100 A fuse and a cable shroud for a fused main switch at 230 V. The listing cites BS EN 60947-3, and the lid can be removed only when the lever is OFF, which stops the enclosure being opened while it is on. The technical table prints an amperage capacity of 80 A even though a 100 A fuse is in the title, so both figures stay on the page. Reviews mention a missing 100 A fuse, a damaged case, and one unit whose springs behind the switch were missing, so the house had no power until that was found. Check the carton before anyone isolates. It is the fused meter switch in this set when both fuses are present, and it is not a 13 A spur and it does not include a surge protector.
Pros
Cons
Best for: You want a fused main switch at the meter and you will check that both the 80 A and 100 A fuses are in the carton.
Less suitable: You need a Type 2 SPD in the same box, a three-phase 4-pole switch, or a 13 A spur.
Specifications
Common questions
Which fuse ratings are in the box?
The bullets say an 80 A fuse and a 100 A fuse, plus a cable shroud. The technical table prints an amperage capacity of 80 A. One review says the 100 A fuse was missing.
When does the lid come off?
The bullet says the lid can be removed only when the lever is in the OFF position.
What faults do reviews name?
Reviews mention a missing fuse, a damaged case, and one unit whose springs behind the switch were missing, so the house had no power until that was found.
The LIDER ULS-F112W-W is a 13 A double-pole fused unit at £9.99 with a glossy screwless white plate, and the star line is 3.9 from 49 reviews. The specification table prints IP00, which is an indoor figure, not a weatherproof one. Several reviews say this plastic plate has no earth terminal, so they joined the earth at a metal back box. Reviews that checked the terminals say live and neutral both open, and reviews say a 13 A fuse and instructions were in the box. The listing cites CE, UKCA and RoHS rather than BS 1363-4. At about twice the price of the BG 852, the screwless look is what you pay for, and the missing earth terminal is the reason to skip it if the back box is not metal. Country of origin is given as China, with a one-year warranty.
Pros
Cons
Best for: You want a screwless 13 A fused plate and you can earth at a metal back box.
Less suitable: The back box is not metal, or you need an outdoor rating or a BS 1363-4 line on the listing.
Specifications
Common questions
Does the LIDER unit switch live and neutral?
The bullet says it is a double-pole switch for live and neutral. Reviews that checked the terminals say both poles open.
Is there an earth terminal on the plate?
The bullet says an earth connection is required only with metal faceplates. Several reviews say this plastic unit has no earth terminal, so they connected the earth at a metal back box.
What IP rating is printed?
The specification table says IP00. That is not an outdoor rating.
The Tiardey CP027688 is titled as a 16 A 4-pin rotary at £11.99, with 3.8 from 13 reviews and an IP65 claim. A bullet says the switch has no arc-extinguishing function and is for disconnecting small circuits, while another bullet says up to 100 A, so the current lines conflict. The technical table prints 440 V AC. The same table says four items, yet two reviews say a single rotary arrived and call the pack claim false. Reviews also call the box plasticky, short of space, and still loose after the fixing is tightened. One review calls it a great isolator without more detail. You should not open it on load, and you should not treat the 100 A line as a meter switch.
Pros
Cons
Best for: You need a small 16 A rotary for a circuit that is already off, and you have read the no-arc-extinguishing line.
Less suitable: You need a 100 A meter isolator, a switch-disconnector you can open on load, or a pack of four.
Specifications
Common questions
Is this a pack of four?
The table says 4 items. Two reviews say a single rotary isolator arrived, and they call the pack claim false.
Can it break a load?
A bullet says the switch has no arc-extinguishing function and is for disconnecting small circuits. The title current is 16 A. Another bullet says up to 100 A. Those lines conflict.
What do reviews say about the box?
Reviews call it plasticky, short of space inside, and still loose after the fixing is tightened. One calls it a great isolator without more detail.
The RiseNova listing is £8.95 and the title says a 16 A 3-pin rotary with an IP65 claim, aimed at ventilation, air conditioning and pumps. The saved listing has no customer-review score and no review text, so the comparison score stays at 0. Voltage is not in the bullets. The technical row gives polycarbonate, 307 g and a box of 10 × 10 × 8 cm, and the model string reads like a marketplace code rather than a catalogue number. Nothing on the page names BS EN 60947-3 or a lock. An IP65 claim without reviews does not show that the box stays shut outdoors or that it can break a load. Buy it only if you already accept an unreviewed 16 A rotary, and do not use the title as evidence that it isolates a house supply.
Pros
Cons
Best for: You have already decided a 16 A 3-pin rotary fits the appliance and you accept a listing with no reviews.
Less suitable: You want UK review evidence, a named standard, or anything other than a 16 A local rotary.
Specifications
Common questions
What current is on the RiseNova title?
The title says 16 A and 3-pin, with an IP65 claim. A voltage figure is not in the bullets.
Are there UK reviews?
The saved listing has no customer-review score and no review text.
Ten amazon.co.uk listings were scored from the product files. This is not a lab test. The weights follow the order a buyer should check: current and the job, then poles, the standard on the listing, lock-off, IP and place, and what else is supplied. A printed amp rating, IP code or standard name is a listing claim. A high star line on a handful of ratings does not outrank a large review file.
Current and job
25%Whole-house switches in this set are 80 A or 100 A. A fixed appliance on a final circuit is 13 A, or 10 A on a fan plate. A 16 A rotary is a local box. A bullet that says up to 100 A on a 16 A title does not change that.
Poles
20%Double pole opens live and neutral on a single-phase appliance. A timer fan with a permanent live needs three poles. Four poles are for three-phase. The pole count has to match the supply you are isolating.
Standard on the listing
20%BS 1363-4 is a 13 A fused connection unit. BS EN 60669-2-4 is a household isolating switch. BS EN 60947-3 is a disconnector, off load, or a switch-disconnector, on load. A listing that says there is no arc extinguishing is not for opening on load.
Lock-off
15%Regulation 12 of the Electricity at Work Regulations 1989 requires the separation to stay secure. A sealable lid or a padlockable handle matters at a meter or outdoors. A domestic rocker does not lock itself.
IP and place
10%IP65 is the outdoor claim on the small rotaries. IP20 and IP00 plates are indoor. An IP rating with no review file is still only a claim on the listing.
What else is supplied
10%A fused main switch that lists 80 A and 100 A fuses is a different job from a Type 2 SPD in the same enclosure, and from a 13 A plate whose table does not list a fuse carrier.
Start with the current and the job, then poles, then the standard named on the listing. Lock-off, the IP rating and what is in the box come after those three. Price comes last. None of the scores is a lab test.
A mains isolation switch disconnects a UK 230 V supply, or part of it, and is meant to stay off while someone works. Householders meet it as a 13 A switched fused connection unit by a boiler, a 10 A three-pole plate by a bathroom fan, a small rotary box outdoors, or a 100 A switch between the meter and the consumer unit. Tell quality by current, poles and the standard on the listing, not by the colour of the plate. Current comes first. Whole-house switches in this set are 80 A or 100 A.
A 16 A rotary is a local box. A bullet that says up to 100 A does not make it the switch beside the meter. Use the current in the title, and treat a conflicting bullet as a conflict.
A listing that says there is no arc-extinguishing function is for disconnecting small circuits that are already off. Do not use that switch as a switch-disconnector. BS EN 60947-3 draws the same line between a disconnector and a switch-disconnector.
The cut-out fuse belongs to the distributor. HSE says lock off, keep the key, and prove dead. Electrical Safety First says check the voltage indicator before and after, and isolate solar or a generator as well. If you cannot do that, stop.
Match the amps to the job before you look at the plate. In this category a whole-house switch is 80 A or 100 A, a fixed appliance on a final circuit is 13 A, and a fan plate is 10 A. A 16 A rotary stays a local box even when a bullet says up to 100 A. Double pole opens live and neutral on a single-phase appliance. A timer fan with a permanent live needs three poles, outside zones 0, 1 and 2. Four poles are for three-phase.
Regulation 12 requires the separation to stay secure. A sealable lid or a padlockable handle matters at a meter or outdoors. A domestic rocker does not lock itself. One fused main switch lets the lid come off only when the lever is OFF. That is a useful limit, and you still check that both fuses are in the carton, because reviews mention a missing fuse and missing springs. IP65 is the outdoor claim on the two small rotaries. IP20 and IP00 are indoor.
Three typical situations, each with a recommendation from this comparison.
You are swapping a 13 A switched fused connection unit, and you stop if the circuit changes inside a bathroom zone. The BG Nexus 852 is about £4.76, with an LED and 4.6 from 1,218 reviews. Fit the fuse the appliance manual asks for. A gas boiler often wants 3 A.
You are choosing a 100 A enclosure and you will check the tails and the carton. The WCED WFIS100 is about £21.00, with 80 A and 100 A fuses listed and a lid that comes off only when the lever is OFF. Reviews mention a missing fuse and missing springs. The cut-out fuse is the distributor’s.
You want a local rotary and you follow the appliance manual rather than the cheapest IP65 title. The Tiardey CP027688 is about £11.99. The listing says there is no arc extinguishing, so you do not open it on load. The title is 16 A. A bullet that says up to 100 A does not make it a meter switch.
In this set of 10 amazon.co.uk listings, the top pick is the BG Nexus 852 at about £4.76, with 4.6 from 1,218 reviews and a score of 92. It is a 13 A double-pole fused connection unit with an LED, and the listing cites BS 1363 Part 4. The best value is the Knightsbridge CU6300N at about £3.74, with 4.6 from 361 reviews and the same score of 92, the lowest price at that score with a real review count. The specification table does not list a fuse carrier. Neither score is a lab test. A 13 A plate does not isolate a 100 A supply.
Knightsbridge CU6300N
Lowest price at this score with a real review count: about £3.74, 4.6 from 361 reviews. Score 92. The specification table does not list a fuse carrier.
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.
Public UK sources are listed below. Shelf prices and star lines are the amazon.co.uk figures in the product files. Checked October 2026.
Expert source (DIY & tools): Charlie White (Charlie DIYte) (external profile) – public expert commentary used as a research source, not as a contributor to our pages.
This page contains affiliate links to amazon.co.uk. If you buy through them, we may earn a commission at no extra cost to you. Prices, stars and review counts are from the UK listings. We did not lab-test these switches.
