BS 7671:2018 Requirements for Electrical Installations will be issued on 2nd July 2018 and is intended
to come into effect on 1st January 2019.
Installations designed after 31st December 2018 will have to comply with BS 7671:2018.
The Regulations apply to the design, erection and verification of electrical installations, also 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 the main changes is given below. (This is not an exhaustive list)
Part 1 Scope, object and fundamental principles
Regulation 133.1.3 (Selection of equipment) has been modified and now requires a statement on the
Electrical Installation Certificate.
Part 2 Definitions
Definitions have been expanded and modified.
Chapter 41 Protection against electric shock
Section 411 contains a number of significant changes. Some of the main ones are mentioned below.
Chapter 42 Protection against thermal effects
Chapter 44 Protection against voltage disturbances and electromagnetic disturbances
Section 443, which deals with protection against overvoltages of atmospheric origin or due to
switching, has been redrafted.
The AQ criteria (conditions of external influence for lightning) for determining if protection against
transient overvoltages is needed are no longer included in BS 7671. Instead, protection against
transient overvoltages has to be provided where the consequence caused by overvoltage (see
(a) results in serious injury to, or loss of, human life, or
(b) results in interruption of public services/or damage to and cultural heritage, or
(c) results in interruption of commercial or industrial activity, or
(d) affects a large number of co-located individuals.
For all other cases, a risk assessment has to be performed in order to determine if protection
against transient overvoltage is required. There is an exception not to provide protection for single dwelling units in certain situations.
Chapter 46 Devices for isolation and switching - A new Chapter 46 has been introduced.
This 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. Also,
switching for the control of circuits or equipment. Where electrically powered equipment is within the
scope of BS EN 60204, only the requirements of that standard apply.
Chapter 52 Selection and erection of wiring systems
Chapter 53 Protection, isolation, switching, control and monitoring
This chapter 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.
Section 534 Devices for protection against overvoltage
This section focuses mainly on the requirements for the selection and erection of SPDs for protection
against transient overvoltages where required by Section 443, the BS EN 62305 series, or as
Section 534 has been completely revised and the most significant technical change refers to the
selection requirements for the voltage protection level.
Chapter 54 Earthing arrangements and protective conductors
Chapter 55 Other equipment
Part 6 Inspection and testing
Section 704 Construction and demolition site installations
This section contains a number of small changes, including requirements for external influences
(Regulation 704.512.2), and a modification to Regulation 704.410.3.6 concerning the protective
measure of electrical separation.
Section 708 Electrical installations in caravan/camping parks and similar locations
This section contains a number of changes including requirements for socket-outlets, RCD protection,
and operational conditions and external influences.
Section 710 Medical locations
Section 715 Extra-low voltage lighting installations
This section contains only minor changes including modifications to Regulation 715.524.201.
Section 721 Electrical installations in caravans and motor caravans
This section contains a number of changes including requirements electrical separation, RCDs,
proximity to non-electrical services and protective bonding conductors.
Section 722 Electric vehicle charging installations
Section 730 Onshore units of electrical shore connections for inland navigation vessels
This is an entirely new section and applies to onshore installations dedicated to the supply of inland
navigation vessels for commercial and administrative purposes, berthed in ports and berths.
Most, if not all, of the measures used to reduce the risks in marinas apply equally to electrical shore
connections for inland navigation vessels. One of the major differences between supplies to vessels
in a typical marina and electrical shore connections for inland navigation vessels is the size of the
Section 753 Floor and ceiling heating systems
This section has been completely revised.
The following main changes have been made within the appendices
Appendix 1 British Standards to which reference is made in the Regulations includes minor changes,
Appendix 3 Time/current characteristics of overcurrent protective devices and RCDs
The previous contents of Appendix 14 concerning earth fault loop impedance have been moved into
Appendix 6 Model forms for certification and reporting
This appendix includes minor changes to the certificates, changes to the inspections (for new
installation work only) for domestic and similar premises with up to 100 A supply, and examples of
items requiring inspection for an electrical installation condition report.
Appendix 7 (informative) Harmonized cable core colours
This appendix includes only minor changes.
Appendix 8 Current-carrying capacity and voltage drop
This appendix includes changes regarding rating factors for current-carrying capacity.
Appendix 14 Determination of prospective fault current
The contents of Appendix 14 concerning earth fault loop impedance have been moved into
Appendix 3. Appendix 14 now contains information on determination of prospective fault current.
Appendix 17 Energy efficiency
This is a new appendix that provides recommendations for the design and erection of electrical
installations including installations having local production and storage of energy for optimizing 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. Much of this appendix will not apply to domestic and
It is intended that this appendix is read in conjunction with BS IEC 60364-8-1, when published in 2018