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Key changes to BS 5839-1:2025 – Part 2

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This was first posted in IET Magazine November 2025.

Main Changes Covered

1. False Alarm Reduction

  • The standard now explicitly highlights the user’s responsibility to investigate and respond to false alarms every time they occur — those commissioning or handing over systems must inform users of this duty.

2. Commissioning and Handover Improvements

  • Before handover, the client or their representative must verify that manual call points have the correct replaceable parts and tools.
  • A cause-and-effect matrix (or equivalent text) explaining how system inputs affect outputs must be provided.

3. Maintenance Changes

  • Routine servicing intervals remain every six months but now allow flexibility of 5–7 months without losing compliance.
  • Control and indicating equipment clocks must be checked/adjusted to ensure accurate event logs.
  • In England & Wales, zone plans must be verified annually to reflect building changes.
  • New cybersecurity clauses require appropriate security measures and authentication to protect systems.

4. Extensions & Modifications

  • A new dedicated section covers how to extend or modify existing fire alarm systems.
  • Extensions must comply with the current standard, even if the original system does not.
  • Redundant devices (e.g., obsolete call points) should be removed or clearly labelled to avoid confusion during emergencies.

5. User Responsibilities

  • If the installation deviates from the standard (e.g., due to compromises in device placement), these variations must now be documented in the logbook, with provided model formats.

Relationship Between BS 5839-1:2025 and BS 7671

The article also clarifies how this fire alarm standard interacts with the UK electrical wiring rules:

  • BS 7671 (IET Wiring Regulations) often references BS 5839 for fire alarm systems under certain regulations.
  • Where differences occur between the two standards regarding fire alarm systems, BS 5839-1:2025 takes precedence.
  • The guidelines emphasise the need for safe isolation — BS 5839 no longer mandates a double-pole isolator, but safe isolation per UK electrical safety regulations remains essential.

Inspection & Testing Notes

  • Although functional testing of fire alarm systems should follow BS 5839-1:2025, electrical inspection and testing (e.g., for certification purposes) remains under BS 7671.
  • Inspectors must clearly agree with clients on what parts of the fire alarm system are included in any electrical inspection report to avoid misunderstandings about coverage.

Overall Message

Staying current with standard changes helps professionals and building duty holders manage fire safety, meet legal obligations, and reduce risk. Specialists should clearly communicate responsibilities, documentation, and limitations of inspections.

Further details – https://electrical.theiet.org/wiring-matters/years/2025/108-november-2025/key-changes-to-bs-5839-12025-part-2/

Product Recall – MK Electric MK Essentials Electrical Three Pin Sockets With Switches

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MK Electric MK Essentials Electrical Three Pin Sockets with Switches

Hazard: The product presents a risk of minor burns, as it has been identified that when the switch on the socket is being switched on, or switched off, whilst it is under load, there is a possibility for an arc flash to occur, for milliseconds.

Corrective action: The products have been withdrawn from the market.

Affected models and barcodes

SKU/ModelUnit barcodePack barcode
MV2747WHI50174909417255017490949721
MV2647WHI50174909417495017490949745
MV2747DPWHI50174909417635017490949769
MV2647DPWHI50174909417875017490949783
MV24344WHI50174909418005017490949806
MV2747MBK50174909633695017490971753
MV2647MBK50174909633835017490971777
MV2747DPMBK50174909634065017490971791
MV2647DPMBK50174909634205017490971814
MV24344MBK50174909634445017490971838
MV2747TTA50174909665445017490974938
MV2647TTA50174909665685017490974952
MV2747DPTTA50174909665825017490974976
MV2647DPTTA501749096660555017490974990
MV24344TTA50174909666295017490975010
MV2747CHA50174909654865017490973870
MV2647CHA50174909655095017490973894
MV2747DPCHA50174909655235017490973917
MV2647DPCHA50174909655475017490973931
MV24344CHA50174909655615017490973955
MV2747CHM50174909676025017490975997
MV2647CHM50174909676265017490976017
MV2747DPCHM50174909676405017490976031
MV2647DPCHM50174909676645017490976055
MV24344CHM50174909676885017490976079
MV2747PRL50174909644275017490972811
MV2647PRL50174909644415017490972835
MV2747DPPRL50174909644655017490972859
MV2647DPPRL50174909644895017490972873
MV24344PRL50174909645025017490972897
MV2747WHI-50174900067525017490007155
Product names
13A 2G SP Switched Socket model
13A 2G DP Switched Socket model
13A 2G SP Switched Socket with Neon model
13A 2G DP SWITCHSOCKET WITH USB PORT

RTS switch-off will force 600,000 households on to new smart meters

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The Radio Teleswitching Service (RTS), also known as the BBC’s long wave signal, is the same signal that powers Radio 4 on long wave, the shipping forecast, and even test cricket broadcasts.

Some electricity meters rely on this signal to switch between peak and off-peak times and to control heating and hot water.

The BBC plans to switch off this signal on 30 June 2025. Similar to the transition from terrestrial to digital TV, this is a nationwide upgrade to a new technology.

When the RTS signal is turned off, your meter could get stuck on the last schedule it used. This means it’ll be out of sync with your tariff’s peak and off-peak hours, which could end up costing you more. 

If you have an RTS meter, it will need to be replaced. Energy company’s will be reaching out via letter or email with details on how to book your meter replacement.

Image below shows a Radio Teleswitching Service (RTS) meter.

1882 1st Edition of the ‘Wiring Rules’ vs. Modern Standards (BS 7671)

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The 1882 Wiring Rules were the first formal attempt to regulate electrical installations in the UK. They were relatively simple by today’s standards but groundbreaking at the time. Below is a comparison of the key aspects of the 1882 edition and modern regulations under BS 7671 (IET Wiring Regulations).

1. Purpose & Scope

  • 1882 Wiring Rules: Focused primarily on safety in electric lighting installations, as electricity was still new and mainly used for street and indoor lighting.
  • BS 7671 (Modern Standard): Covers all aspects of electrical installation, including residential, industrial, and commercial buildings, and considers modern hazards such as EMF interference and smart technology.

2. Earthing (Grounding)

  • 1882: The concept of earthing was not well-developed. The rules mentioned ensuring metallic parts were insulated but did not require a standardized earthing system.
  • Modern BS 7671: A comprehensive earthing system is now required, including TN, TT, and IT systems, bonding of metalwork, and protective earth connections to avoid electric shock risks.

3. Fuses & Circuit Protection

  • 1882: Basic fuse protection was required to prevent short circuits and fires, but the ratings were not standardized.
  • Modern BS 7671: Includes MCBs (Miniature Circuit Breakers), RCDs (Residual Current Devices), and AFCIs (Arc Fault Circuit Interrupters), offering much greater safety and sensitivity to electrical faults.

4. Insulation & Wiring Materials

  • 1882: Wires were often cotton-wrapped copper conductors, sometimes with gutta-percha insulation (a natural rubber-like material). This was highly flammable.
  • Modern BS 7671: Uses PVC, LSZH (Low Smoke Zero Halogen), and fire-resistant cables, ensuring higher durability, heat resistance, and reduced toxicity in case of fire.

5. Voltage & Frequency

  • 1882: No fixed standard for voltage or frequency, but most systems operated at around 100–250V DC.
  • Modern BS 7671: UK now standardizes at 230V AC, 50Hz, ensuring compatibility across appliances and systems.

6. Installation & Testing

  • 1882: Installations were often done without proper testing, leading to numerous fires and shocks.
  • Modern BS 7671: Requires full inspection & testing before energizing a circuit, including:
    • Insulation resistance testing
    • Earth continuity testing
    • Polarity checks
    • RCD testing
    • Periodic Electrical Installation Condition Reports (EICR)

7. Fire Safety

  • 1882: Fire risks were addressed mainly by keeping conductors insulated and properly supported.
  • Modern BS 7671: Introduces fire-resistant cables, fire barriers, emergency lighting, and mandatory RCDs in many circuits to prevent overheating and faults.

8. Evolution of the Wiring Rules

  1. 1882 – 1st Edition: Basic safety principles for early electrical lighting.
  2. 1903 – 5th Edition: Introduced proper fuse sizing.
  3. 1947 – 13th Edition: Recognized earthing as essential.
  4. 1981 – 15th Edition: Formalized earthing and insulation resistance testing.
  5. 2008 – 17th Edition: Introduced mandatory RCD protection.
  6. 2018 – 18th Edition (Current): Focuses on arc fault detection, energy efficiency, and EV charging points.

Conclusion

The 1882 Wiring Rules were a vital first step in electrical safety, but they were basic and lacked modern protective measures. Today’s BS 7671 ensures much higher levels of safety, efficiency, and compatibility with modern technology.

Would you like details on a specific aspect, such as historical cases of early electrical failures or how regulations differ internationally?

IET and BSI urges electrical industry to have its say on IET Wiring Regulations

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The Institution of Engineering and Technology (IET) and BSI are calling on the electrical industry to have its say on an amendment to the current BS 7671:2018 Amendment 2 (2022) + Amendment 3 (2024), which will go to DPC (Draft for Public Consultation) on 7 August 2024. BS 7671 is the Requirements for Electrical Installations: IET Wiring Regulations.

  • Draft for Public Consultation open from 7 August 2024 to 3 November 2024.
  • Latest amendment expected to be published in 2026

The amendment, known as Amendment 4, has been long-scheduled and will incorporate changes to harmonised standards at European level which the UK has to adopt within a certain time period.

The DPC for Amendment 4 is hot on the heels of Amendment 3 which has just been published and is available as a free-to-download PDF ‘bolt-on’ to Amendment 2 from the IET and BSI websites.

Amendment 4 is expected to be published in 2026, until that time electrical installers need to have a copy of Amendment 2 (2022) – the ‘brown book’ and Amendment 3 (2024) free PDF bolt-on to be up to date. Join the IET for a live webinar at midday on Wednesday 7 August 2024 as we announce the proposed changes and how they may affect you.

Comments on the DPC for Amendment 4 can be submitted through BSI’s Standards Development portal between 7 August 2024 to 3 November 2024.

IET’s Mark Coles, Head of Technical Regulations, said: “The days of the ‘evergreen electrician’ are gone. Changes in technology, installation practices and developments in standardisation are happening so quickly. It’s therefore so important that installers and designers stay well-informed of what’s happening in the industry. The IET is the authority for electrical installations in the UK and ensures that the wiring regulations committee, JPEL/64, carefully considers all necessary updates to the Regulations to ensure they best meet the needs of industry.

“It is intended that this Amendment will include requirements for Stationary Secondary Batteries, low voltage generating sets, power over ethernet, energy efficiency and functional earthing and functional-equipotential-bonding for Information and Communication Technology Equipment and Systems (ICT). Each area of change is a response to fast evolving technologies.”

BSI’s Dan Palmer, Associate Director, Committees, said: “BSI is proud to have been partners with the IET for over 30 years.  As electrification increases in the UK, we can all benefit from supporting high standards of safety. Keeping this critical standard on electrical installations updated is vital to ensure continued safety. We urge people with an interest to look at the suggested changes made in the draft and provide your comments.”

The Chair of JPEL/64, Graham Kenyon, said: “The members and officers of JPEL/64 invite anyone involved in the industry to contribute to the standard by providing comments on the Draft. We will initially focus on addressing comments related to the intent of technical changes put forward. Comments made on other parts of the standard will be considered in future work of JPEL/64, both for BS 7671 and international work. I extend personal thanks to all the organisations and individuals that have contributed to this Draft so far, both at National and International level.” 

The IET and BSI jointly manage JPEL/64, the committee responsible for BS 7671.