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Best mains isolator switch for the job in front of you

Updated: October 2026

You already know you need a mains isolator, and you want one amazon.co.uk listing to start from rather than a star-sorted grid. The best mains isolator switch in this set depends on the job. A 13 A boiler spur, a 10 A fan and a 100 A enclosure beside the meter are not rivals. This page names the listing that matches each of those jobs, then the ones to leave on the shelf, including who should skip them. Prices and the full table are on the [mains isolation switch comparison](/hub/electrical-equipment/mains-isolation-switch). There is no lab test behind the scores, and a high star line is not a measured isolation result.

You already know you need a mains isolator, and you want one amazon.co.uk listing to start from rather than a star-sorted grid. The best mains isolator switch in this set depends on the job.

Our top picks

BG BG Nexus 852

Best overall

BG BG Nexus 852
9.2/10about £4.76
View offer
Knightsbridge Knightsbridge CU6300N

Best value

Knightsbridge Knightsbridge CU6300N
9.2/10about £3.74
View offer
WCED WCED WFIS100

Rank 3

WCED WCED WFIS100
8.6/10about £21.00
View offer
On this page
  1. 1.Do not rank these by stars
  2. 2.For a 13 A spur, start with the BG 852
  3. 3.For the meter, start with WFIS100
  4. 4.Leave these on the shelf for that job

Do not rank these by stars

The highest star line in the file is 4.8 from seven ratings, on the BG Nexus 951 at £5.20. The BG Nexus 852 is 4.6 from 1,218 ratings at £4.76. Seven opinions can sit above a thousand without telling you more about the switch. The comparison marks the 852 as the top pick because the score of 92 sits on the largest review count, not because a laboratory ranked the plates. The Knightsbridge CU6300N is marked best value at £3.74, with 4.6 from 361 reviews and the same score of 92. Its table does not list a fuse. The spur and the meter switch are different ASINs, and the star sort will not show you that.

For a 13 A spur, start with the BG 852

The BG Nexus 852 is the straightforward 13 A switched fused connection unit in this set. It is double pole, it has an LED, the plate is round and white, the listing cites BS 1363 Part 4, and the bullets ask for a 35 mm back box. One review reports melting. That is one report against a large file, not a failure rate. You still fit the fuse the appliance asks for. A gas boiler often wants 3 A in a double-pole spur. Choose the BG Nexus 951 at £5.20 only when you specifically want the square edge and you accept seven ratings. Skip the LIDER plate if the plastic front has nowhere for the earth to land. Several reviewers joined the earth at a metal back box.
BG BG Nexus 852

Testsieger

BG BG Nexus 852
9.2/10about £4.76
View offer

For the meter, start with WFIS100

The fused main switch to open first is the WCED WFIS100 at £21.00, with 4.3 from 65 reviews. The bullets include an 80 A fuse, a 100 A fuse and a cable shroud. The listing cites BS EN 60947-3. The lid can be removed only when the lever is off. The technical table prints 80 A while the title includes a 100 A fuse, so you check the carton. Reviews mention a missing fuse and missing springs. Look at the WCED WEC440SP at £30.00 only when a Type 2 surge protective device in the same enclosure is the point. The WCED WEC4400 is the three-phase row, not the single-phase house default. Tails and the cut-out are on the meter isolator switch page.

Leave these on the shelf for that job

The Tiardey CP027688 at £11.99, 3.8 from 13 reviews, is titled 16 A and 4-pin, with an IP65 claim. A bullet says there is no arc extinguishing and that it is for disconnecting small circuits. Another bullet says up to 100 A. A listing that says there is no arc extinguishing is not a switch-disconnector. Two reviews say one switch arrived, not four. None of that is a 100 A outdoor switch. RiseNova at £8.95 has no star rating and no review text, so an IP65 title is not evidence. The Knightsbridge CU6300N is the best value plate at £3.74 if you need a double-pole switch and you do not need a fuse in the carrier. It is the wrong pick when the manual asks for a fused spur. The BG NBS15-01 at £7.99, 4.6 from 703, is a 10 A three-pole fan isolator. Ignore it unless the appliance is that fan.

Common questions

Which listing is the straightforward 13 A spur?
Start with the BG Nexus 852, ASIN B004TRRQC0, at £4.76. It is a switched fused connection unit with an LED, double pole, BS 1363 Part 4 on the listing, and 4.6 from 1,218 reviews. One melt report sits in that file. It is a 13 A spur, not a meter isolator. The square-edge 951 is the alternative only if you accept seven ratings.
Which one is the fused main switch?
The WFIS100, ASIN B08J3YFQTW, at £21.00. The listing supplies an 80 A fuse and a 100 A fuse, cites BS EN 60947-3, and the lid comes off only in the off position. Check both fuses are in the carton. Reviews include a missing fuse and a unit with missing springs. The table's 80 A line and the 100 A fuse in the title both stay visible.
Who should skip the LIDER plate?
Skip the LIDER ULS-F112W-W if the back box is not metal, or if you wanted BS 1363-4 named on the listing. Reviews say this plastic screwless plate has no earth terminal. It is £9.99, IP00, and 3.9 from 49 reviews. The screwless look is the extra over the BG 852, and it is a poor trade when the earth has nowhere to land on the plate.
Is the 4.8 rating the best evidence?
No. That 4.8 is seven ratings on the Nexus 951. The 852's 4.6 comes from 1,218 ratings at a similar price. A small file can look perfect and still tell you less. The comparison does not treat seven stars as a test. There is no laboratory result for any ASIN on this page.
Which rotary can I treat as a 100 A outdoor switch?
None of the amazon.co.uk rotaries kept in this set. Tiardey and RiseNova are 16 A titles. Tiardey's up to 100 A bullet conflicts with the 16 A title and with the line that says there is no arc extinguishing. A 100 A IP65 rotary from a trade seller was in a higher price band, about £50 to £67 including VAT.
When is the SPD enclosure the one to look at?
Look at the WEC440SP, at £30.00, when you want a Type 2 surge protective device in the same enclosure as a 100 A isolator. That is a listing claim aimed at BS 7671 surge protection, not a certificate in the file. Skip it if you only wanted the fused WFIS100, or if 25 mm² tails will not enter cleanly. Reviewers feed it from the top.

Related pages

Mains isolation switch buying guide

Rotary isolator vs fused spur

Mains isolation switch

How to isolate electrics safely before any UK work

Meter isolator switch: what sits beside your meter

Sources

Public UK sources are listed below. Shelf prices and star lines are the amazon.co.uk figures in the product files. Checked October 2026.

  1. HSE HSR25, Electricity at Work Regulations 1989, regulation 12 (retrieved October 2026)
  2. HSE, work near electricity (retrieved October 2026)
  3. Electrical Safety First, Best Practice Guide 2 issue 4.3 (retrieved October 2026)
  4. IET Wiring Matters, July 2026, Table 537.4 (retrieved October 2026)
  5. IET extractor-fan FAQ (retrieved October 2026)
  6. Approved Document P 2013 (retrieved October 2026)
  7. SI 2012/3119, regulation 12(6A) (retrieved October 2026)
  8. UK Power Networks, a typical domestic supply (retrieved October 2026)