The IET Wiring Regulations is the national standard for electrical installations in domestic, commercial and industrial settings. It is the essential standard for all those concerned with the design, installation, certification and maintenance of electrical installations. Amendment 4:2026 is a major update to BS 7671:2018, The IET Wiring Regulations, Eighteenth Edition.
BS 7671:2018+A4:2026 is a consolidated publication which incorporates all previous amendments to the standard. New inclusions within BS 7671:2018+A4:2026 are: Stationary Secondary Batteries where the purpose is for electrical storage and supply of electrical installations; Functional earthing and functional equipotential bonding for information and communication technology (ICT) equipment and systems; a new section on Power over Ethernet (PoE) and a major revision of Section 710 Medical Locations and the inclusion of a schedule of test results for recording the resistance of supplementary protective equipotential bonding conductors.
From 15th April 2026 you will need to have a copy of BS 7671:2018+A4:2026, known as 'the orange book'.
Introduction to BS 7671:2018
Introduction to Amendment 1:2020
Introduction to Amendment 2:2022
Introduction to Amendment 3:2024
Introduction to Amendment 4:2026
Part 1: Scope, object and fundamental principles
Chapter 11: Scope
Chapter 12: Object and effects
Chapter 13: Fundamental principles
Part 2: Terms and definitions
Symbols used in BS 7671
Abbreviated terms used in BS 7671
Part 3: Assessment of general characteristics
Chapter 30: Assessment of general characteristics
Chapter 31: Purposes, supplies and structure
Chapter 32: Classification of external influences
Chapter 33: Compatibility
Chapter 34: Maintainability
Chapter 35: Safety services
Chapter 36: Continuity of service
Part 4: Protection for safety
Chapter 41: Protection against electric shock
Chapter 42: Protection against thermal effects
Chapter 43: Protection against overcurrent
Chapter 44: Protection against voltage disturbances and electromagnetic
disturbances
Chapter 45: Not used
Chapter 46: Isolation and switching
Part 5: Selection and erection of equipment
Chapter 51: Common rules
Chapter 52: Selection and erection of wiring systems
Chapter 53: Protection, isolation, switching, control and monitoring
Chapter 54: Earthing arrangements and protective conductors
Chapter 55: Other equipment
Chapter 56: Safety services
Part 6: Inspection and testing
Chapter 61: Not used
Chapter 62: Not used
Chapter 63: Not used
Chapter 64: Initial verification
Chapter 65: Periodic inspection and testing
Part 7: Special installations or locations
Section 700 General
Section 701: Locations containing a bath or shower
Section 702: Swimming pools and other basins
Section 703: Rooms and cabins containing sauna heaters
Section 704: Construction and demolition site installations
Section 705: Agricultural and horticultural premises
Section 706: Conducting locations with restricted movement
Section 708: Electrical installations in caravan / camping parks and similar
locations
Section 709: Marinas and similar locations
Section 710: Medical locations
Section 711: Exhibitions, shows and stands
Section 712: Solar photovoltaic (pv) power supply systems
Section 714: Outdoor lighting installations
Section 715: Extra-low voltage lighting installations
Section 716: Power over ethernet
Section 717: Mobile or transportable units
Section 721: Electrical installations in caravans and motor caravans
Section 722: Electric vehicle charging installations
Section 729: Operating and maintenance gangways
Section 730: Onshore units of electrical shore connections for inland
navigation vessels
Section 740: Temporary electrical installations for structures, amusement
devices and booths at fairgrounds, amusement parks and circuses
Section 753: Heating cables and embedded heating systems
Part 8: Functional requirements
Chapter 81: Low voltage electrical installations: functional aspects - energy
efficiency
Chapter 82: Prosumer's low voltage electrical installations
Appendices
Appendix 1 (Normative): British standards and other standards or documents to
which reference is made in BS 7671
Appendix 2 (Informative): Statutory regulations and associated memoranda
Appendix 3 (Informative): Time/current characteristics of overcurrent
protective devices
Appendix 4 (Informative): Current-carrying capacity and voltage drop for
cables
Appendix 5 (Informative): Classification of external influences
Appendix 6 (Informative): Model forms for certification and reporting
Appendix 7: Deleted by BS 7671:2018+A2:2022
Appendix 8 (Informative): Current-carrying capacity and voltage drop for
busbar trunking and powertrack systems
Appendix 9 (Informative): IT, multiple source, DC and other systems
Appendix 10 (Informative): Protection of conductors in parallel against
overcurrent
Appendix 11 (Informative): Warning and user instruction labels
Appendix 12: Not used
Appendix 13 (Informative): Escape routes and fire protection
Appendix 14 (Informative): Determination of prospective fault current
Appendix 15 (Informative): Ring and radial final circuit arrangements,
Regulation 433.1
Appendix 16 (Informative): Devices for protection against overvoltage
Appendix 17: Deleted by BS 7671:2018+A4:2026
Table of figures
Table of tables
Index
