Changes to 18th Edition BS 7671:2018 Requirements for Electrical Installations

Summary of new additions to be included in the 18th Edition BS 7671:2018

Requirements for Electrical Installations.


Weblight provides Lighting and Electrical solutions including LED Lighting Upgrades, Compliance Testing and Maintenance to organisations across the UK.



Ahead of the publication of BS 7671:2018, Stephen Williams, Weblight’s NICEIC lead Qualifying Supervisor has reviewed the changes that will be included in the 18th Edition of the IET Wiring Regulations, according to the Institution of Engineering and Technology (IET) and the British Standards Institution (BSI).

The 18th Edition of the IET Wiring Regulations is the essential publication for all professionals working in the electrical industry.  The revision is due to be released on 2nd July 2018, this will form the national standard to which all new and amended electrical installations in the UK are to comply.  The IET is now urging all electrical professionals to ensure they are familiar with the changes before the new requirements come into force on 1st January 2019.

From 1st January 2019, it will be a requirement that all electrical installations designed after this date comply with BS 7671:2018, 18th Edition (2018).

The New Regulations apply to the: Design, Erection, Verification of electrical installations and additions and alterations to existing installations.

Existing installations that have been installed in accordance with earlier editions of the Regulations may not comply with this edition in every respect. This does not necessarily mean that they are unsafe for continued use or require upgrading.



A summary of relevant key changes in the 18th Edition

Regulation 133.1.3 (Selection of equipment) has been modified and now requires a statement on the Electrical Installation Certificate.

Regulation 411.3.3 has been revised and now applies to socket-outlets with a rated current not exceeding 32A. There is an exception to omit RCD protection where, other than a dwelling, a documented risk assessment determines that RCD protection is not necessary.

A new Regulation group (419) has been inserted where automatic disconnection according to Regulation 411.3.2 is not feasible, such as electronic equipment with limited short-circuit current.

Chapter 42 Protection against thermal effects

A new Regulation 421.1.7 has been introduced recommending the installation of arc fault detection devices (AFDDs) to mitigate the risk of fire in AC final circuits of a fixed installation due to the effects of arc fault currents.

Chapter 46 Devices for isolation and switching 

A new Chapter 46 has been introduced which deals with non-automatic local and remote isolation and switching measures for the prevention or removal of dangers associated with electrical installations or electrically powered equipment.

Chapter 52 Selection and erection of wiring systems

Regulation 521.11.201 which give requirements for the methods of support of wiring systems in escape routes, has been replaced by a new Regulation 521.10.202.

Chapter 53 Protection, isolation, switching, control and monitoring has been completely revised and deals with general requirements for protection, isolation, switching, control and monitoring and with the requirements for selection and erection of the devices provided to fulfil such functions, including surge protection devices.
Chapter 54 Earthing arrangements and protective conductors

Two new regulations (542.2.3 and 542.2.8) have been introduced concerning earth electrodes.

Two further new regulations (543.3.3.101 and 543.3.3.102) have been introduced. These give requirements for the insertion of a switching device in a protective conductor, the latter regulation relating to situations where an installation is supplied from more than one source of energy.


Chapter 55 Other equipment

Regulation 550.1 introduces a new scope.

New Regulation 559.10 refers to ground-recessed luminaires, the selection and erection of which shall take account of the guidance given in Table A.1 of BS EN 60598-2-13.

Appendices – Changes have been made to the majority of the appendices and a new Appendix (17 Energy efficiency)  provides recommendations for the design and erection of electrical installations including installations having local production and storage of energy for optimising the overall efficient use of electricity.  The recommendations within the scope of this appendix apply for new electrical installations and modification of existing electrical installations.


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