BS Numbers for Protective Devices

Last Technical Review: June 2026

A quick identification guide for the BS numbers of fuses, circuit breakers, RCBOs, RCDs and more — as referenced on test certificates and EICRs.

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On-site reference for electricians

Match the device in front of you to the correct BS number before completing your schedule of test results.

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When completing electrical installation certificates, EICRs or minor works paperwork, you are often required to record the British Standard number of the protective device fitted. This reference table lists the most common BS numbers for domestic and light-commercial protective devices, with photos to help you identify what is in the board, fuseway or socket outlet.

BS numbers identify the type of device — not the manufacturer or rating. Always verify the rating marked on the device itself and cross-check against the circuit design.

Protective Device BS Number Reference

BS Standard Description Device
BS 1361 Cartridge Fuses (Consumer Unit Type) BS 1361 consumer unit cartridge fuses of various ratings
BS 1363 Plug Top Fuses BS 1362 plug top cartridge fuses used in BS 1363 plugs
BS 1363 13A Plug Tops UK BS 1363 three-pin plug and socket outlet
BS 3036 Rewireable Fuses Consumer unit with rewirable fuse carriers
BS 3871 Miniature Circuit Breaker (Old Style) Consumer unit with older-style circuit protection devices
BS 60898 Miniature Circuit Breakers Modern miniature circuit breakers on a DIN rail
BS 7288 RCD Sockets Socket outlet with integrated RCD test and reset buttons
BS 88 Cartridge Fuses (General Purpose) Cartridge fuse for general-purpose HRC applications
BS EN 60947-3 Main Isolators DIN rail load switch / main isolator
BS EN 61008 Main RCDs Two-pole residual current device for main RCD protection
BS EN 61009-1 RCBOs RCBO combining MCB and RCD protection in one device
BS EN 62606 AFDDs Arc fault detection device for DIN rail mounting

Practical tips

  • BS 1361 vs BS 1362: BS 1361 fuses are used in consumer units and are physically larger than the BS 1362 fuses found inside 13 A plug tops (BS 1363).
  • BS 3871 vs BS 60898: BS 3871 covered older plug-in or non-standard MCBs; modern DIN-rail MCBs are to BS EN 60898 (often still referred to as BS 60898).
  • RCD vs RCBO: BS EN 61008 is RCD-only (no overcurrent protection); BS EN 61009-1 is the combined RCBO.
  • Device markings are usually on the front or side of the unit — photograph unclear labels for your records if completing an EICR.

Related guides

Last Updated: June 2026

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Certificate completion checklist

  • Record the correct BS number for each protective device on the schedule
  • Verify device ratings match circuit design and cable size
  • Confirm RCD/RCBO test buttons operate correctly
  • Photograph illegible or missing device markings
  • Cross-reference with manufacturer data if the BS marking is absent
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