Tag Archives: 18th Edition Wiring Regulations

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/

Wiring Matters – Issue 90 – May 2022

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Lets take a look at what is in the May 2022 issue of Wiring Matters (Issue 90)

BS 7671: Chapter 42 – Protection against fire

With the introduction of the 15th Edition of the IEE Wiring Regulations in 1981 the UK aligned the requirements of the regulations with the International Electrotechnical Commission (IEC) worldwide electrical installation standard IEC 60364.

Coming up: Guide to Earthing and Bonding for AC Electrified Railways

We think readers of Wiring Matters will be interested in the forthcoming publication from IET Codes & Guidance. Guide to Earthing and Bonding for AC Electrified Railways aims to assist infrastructure owners, railway designers and installation contractors in adopting a harmonised approach towards earthing and bonding design philosophy for 25 kV railway infrastructure.

Draft for Public Comment coming soon: Code of Practice for Grid-connected Solar Photovoltaic Systems, 2nd Edition

We are happy to announce that in the coming weeks we will be sending Code of Practice for Grid-connected Solar Photovoltaic Systems, 2nd Edition out for its consultation period.

We want to hear from you

With the introduction of BS 7671:2018+A2:2022 and the updates to the associated publications that come with that, we want to hear from you, our readers. Do you have a question you want answered in a forthcoming article, or maybe you have a particular area that deserves an investigation by our team? Do you want to debate a point made in the past by one of our articles?

Wiring Matters – Issue 87 – September 2021

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It’s that time again, here is what you can find in Issue 87 (September 2021) of the IET’s Wiring Matters magazine.

Evaluation and metrics

The design framework of IEC 60364-8-1 provides guidance on a more energy-efficient electrical installation through careful placement of electrical supplies, considered infrastructure design, controls and energy management. All of this is designed to minimise energy loss in the distribution of electricity and reduce energy consumption at the point of use in the electrical installation, whilst still maintaining a suitable and comfortable environment for the end-users.

Electrical Safety Standards in the Private Rented Sector

The IET’s Technical Helpline continues to be inundated with queries relating to the practicalities of implementing the Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020 (ESSPRS). These place legal requirements on landlords to ensure that every electrical installation in a privately rented residential premise is inspected and tested at intervals of no more than 5 years, by an electrically qualified and competent person.

Myth Busters #7 – Out with the old, in with the new?

The introduction of the 18th Edition of the IET Wiring Regulations (BS 7671:2018) saw a new regulation buried in Section 536 Co-ordination of electrical equipment for protection, isolation, switching and control.

Back to the Forum – Current-carrying capacity of cables buried in the ground

A question that arises periodically on the IET Engineering Communities forum concerns the current-carrying capacity of cables buried in the ground, in particular, the data used to select the appropriate cross-sectional area (CSA) of live conductors.

TT earthing considerations

TT earthing facilities are installed when the distributor does not provide a TN earthing system or when circumstances dictate that a TN earthing system cannot be used. A look at the considerations and what you need to know.

You can take a look at the full edition via the link below –

https://electrical.theiet.org/wiring-matters/years/2021/87-september-2021/

Can I install a metal consumer unit with a TT earthing system?

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High earth fault loop impedance values associated with TT earthing systems mean the earth fault current level is unlikely to be sufficient to operate the distributor’s protective device within the permitted time of 1 second, as required in Regulation 411.2.4, or at all in some cases, depending on Earth resistance values.

There is nothing to prevent a metal consumer unit being installed with a TT earthing system, but it’s important to ensure that an earth fault cannot develop between the meter tails and the metallic enclosure before the RCD.

Methods of reducing an earth faults include keeping the meter tails as short as possible, the installation of proprietary clamps and glands to secure the cables and prevent strain on the terminations, minimising the risk of damage to the meter tails and a subsequent earth fault.

Order Now – Eighteenth Edition – BS 7671:2018 (Electrical Regulations)

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You can now order your copy of the Requirements for Electrical Installations, IET Wiring Regulations, Eighteenth Edition, BS 7671:2018 (Electrical Regulations) and the On-Site Guide (BS 7671:2018) (Electrical Regulations) 

Requirements for Electrical Installations, IET Wiring Regulations, Eighteenth Edition, BS 7671:2018 (Electrical Regulations)

The IET Wiring Regulations are of interest to all those concerned with the design, installation and maintenance of electric wiring in buildings. The market includes electricians, electrical contractors, consultants, local authorities, surveyors and architects. This book will also be of interest to professional engineers, as well as students at university and further education colleges. All users of the IET Wiring Regulations need to be aware of the coming changes in the 18th Edition (BS 7671:2018). This is intended to come into effect on 1st January 2019, although industry needs to start preparing for this from its point of publication (2nd July 2018).

On-Site Guide (BS 7671:2018) (Electrical Regulations) Spiral-bound – 2 Jul 2018

The On-Site Guide is an essential guide to BS 7671. It incorporates the extensive changes in BS 7671:2018, making this a vital guide for keeping up to date. It enables the competent electrician to deal with installations (up to 100 A, 3-phase) providing essential information in a convenient, easy-to-use format. The 18th Edition IET Wiring Regulations publishes in July 2018 and comes into effect on 1st January 2019. All new installations from this point must comply with BS 7671:2018.

     

All above links on this page offer you the ability to order the above publications via Amazon directly.