From humble beginnings, the IET Wiring Regulations quickly became the standard for electrical installation in the UK. With the latest amendment to the 18th Edition set for publication on 15 April 2026, Rob Shepherd looks at the development of ‘The Regs’.
As well as being the same year that Britain’s first electric trams started running in East London, Queen Victoria opened the Royal Courts of Justice and Old Etonians beat Blackburn Rovers 1-0 in the FA Cup Final, 1882 also saw the Society of Telegraph Engineers and Electricians publish the first incarnation of the Wiring Regulations. Although it was just a simple four page publication, its impact is still being felt today, so let’s look back over 144 years of this important document.
1882
In 1881, the world’s first public electricity supply was switched on in Godalming, Surrey, replacing gas powered streetlights with electric ones. The following year, this milestone was followed by the publication of Rules and Regulations for the Prevention of Fire Risks Arising from Electric Lighting.
Circulated amongst government departments and known as the Wiring Rules, it featured just 21 items and contained the following advice, “Fuses are the very essence of safety. They should always be encased in incombustible cases. Even if the wires become warmed by the ordinary current, it’s a proof that they are too small for the work they have to do and ought to be replaced by larger wires”.
1888 and 1897
The 2nd Edition, published in 1888, built on the success of the 1st Edition by introducing several new rules. The 3rd Edition followed in 1897 and was retitled General Rules Recommended for Wiring for the Supply of Electrical Energy. In 1889, the Society of Telegraph Engineers and Electricians became the Institution of Electrical Engineers (IEE), marking the beginning of what became known as the IEE Wiring Regulations.
1903
In the year of the first transatlantic radio broadcast between the United States and Great Britain, the 4th Edition introduced definitions of electrical equipment, as well as some rather interesting advice. Regulation 48 stated: “Fuses may be considered too large if they are not warm to the touch on full load and too small if they hiss when moistened”.
It is also at this point that certification comes into play. It was stated that there should be a signed declaration confirming that an installation is compliant with the current rules.
1907, 1911 and 1916
As electricity became more prominent within homes and workplaces, the 5th Edition, 6th Edition and 7th Edition were published in relatively quick succession to account for the array of new electrical products being marketed to consumers. The 7th Edition referred to electric tablecloths, which were the height of fashion at the time and lit up in the dark. With an electric current running through them there is no record if what happened when drinks were spilt.
1924
With Ramsay MacDonald in power as the first Labour prime minister, the 8th Edition – Regulations for the Electrical Equipment of Buildings – saw the first instance of different cable sizes being mentioned. It also coincided with the formation of the forerunner to the NICEIC – the National Register of Electrical Installation Contractors (NREIC) – which was set up to help the public identify competent contractors, improve the efficiency and status of contractors, and to establish a register.
1927
While the British Broadcasting Company was renamed the British Broadcasting Corporation (BBC), by the time that that the 9th Edition was introduced the NREIC had a mere 202 contractors on its register. However, this number grew significantly in the subsequent years.
1934
The 10th Edition saw different sections introduced, which helped contractors navigate what was becoming a comprehensive document. In 1937, the Electricity Supply Regulations granted suppliers the authority to inspect the rapidly increasing number of electrical installations before connecting them to the public supply, ensuring they met safety standards. However, the only statutory requirement was an insulation test.
1939
In the same year that World War II broke out the 11th Edition was published. A series of amendments followed with a revised issue in 1943, a reprint with minor amendments in 1945, a supplement issued in 1946 and a revised section in 1948. During this period the concept of the ring circuit became popular and this was reflected in subsequent editions.
1950
With various versions of the 11th Edition, it wasn’t until 1950 that the 12th Edition appeared, which was followed by a supplement issued in 1954 named Regulations for the Electrical Equipment of Buildings. Meanwhile, in a nod to the future, Alan Turing’s paper Computing Machinery and Intelligence was published in Mind.
1955
Amidst the publication of the 13th Edition, it was a big year for the electrical contracting industry. The electricity supply industry began showing greater interest in installation matters and even proposed replacing the IEE Wiring Regulations with a Code of Minimum Wiring Practice.
The proposal was eventually dropped, but it led to the formation of NICEIC in 1956. The first roll of approved contractors was published in 1957 and listed 3,511 individuals. The NICEIC came in at just the right time, as 13th Edition was suitably worded for enforcement, together with non-mandatory recommendations for good practice. It was reprinted in 1958, 1961, 1962 and 1964, and it was the first time that PVC cables were mentioned.
1966
1966 was a year of firsts. England won the World Cup for the first and only time and the 14th Edition was first time that the word ‘bonded’ was mentioned in the definitions. It was reprinted seven times – the reprint in 1970 being the first in metric units.
1981
The 15th Edition of the Wiring Regulations marked a transition from the Swinging Sixties to the Decade of Decadence, reflecting a changing social and technical landscape. It also recognised the growing need for European harmonisation by aligning UK standards with CENELEC.
Many existing practices were expanded or enhanced, such as supplementary equipotential bonding. Regulation 413-7 required the bonding of all metallic items, which led to the installation of supplementary equipotential bonding of general metallic items such as baths, ceiling grids, handrails, kitchen sinks, radiators and pipework at boilers. This was altered in future editions.
When it was published with a cover price of £50, it was also decided that future reprints would feature one of five different coloured covers – red, green, yellow, blue, and brown. A new edition would then be issued whenever the brown covered reprint required updating.
However, the 15th Edition was mired in controversy, with Electrical Times claiming that it was “beyond the ken of ordinary contractors” and that it was a “green light for cowboys”. In an effort to allay concerns, in February 1977, NICEIC Chief Engineer Tom Howell said that it will “not lead to radical changes”.
1991
Certificates as we know them – including test results and inspection schedule – came about in the 16th Edition Requirements for Electrical Installations. It was also formally adopted as a British Standard – BS 7671 – in 1992 and was reprinted four times.
2004
In 2004 Part P of the Building Regulations became law. Its full title was BS 7671:2001 Requirements for Electrical Installations (Incorporating Amendments No 1:2002 and No 2:2004), The IEE Wiring Regulations (16th Edition).
Part P introduced a legal requirement stipulating that all work on fixed electrical installations in dwellings, as well as in associated buildings such as garages, outbuildings and annexes, must comply with the relevant safety and technical standards. This regulation was designed to ensure that electrical work met consistent safety criteria, reducing the risk of accidents, fires and injuries, while also providing clear guidance for electricians, inspectors and homeowners on the proper standards and practices for installing, modifying or maintaining electrical systems.
2006 and 2007
2006 saw the formation of the Institution of Engineering and Technology (IET). It came into existence after the IEE merged with the Institution of Incorporated Engineers (IIE).
The following year saw the publication of the 17th Edition after a committee representing the electrical industry reviewed the 16th Edition for the last two years and received over 2,500 comments from industry during a public consultation period. Amid its 463 pages and 1,274 regulations it paid particular attention to the use of residual current devices (RCDs) and required that an RCD not exceeding 30mA be provided for socket outlets up to 20A that are for general use by ‘ordinary persons’.
2013 and 2015
The 17th Edition was amended in 2013 with a new section for all involved in the installation of electric vehicle charging points and two years later a third and final amendment was introduced to create BS 7671:2008+A3:2015. It stated that switchgear assemblies – including consumer units – must have enclosures made from a suitable non-combustible material, or be installed in a cabinet or enclosure comprised from a suitable non-combustible material.
2018
The 18th Edition – BS 7671:2018 Requirements for Electrical Installations – was issued on 2nd July 2018 and came into effect on 1st January 2019.
Along with new information about protection against electric shock, fire, voltage disturbances and electromagnetic disturbances, there was a new section on protection against thermal effects, which recommended the installation of arc fault detection devices (AFDDs) to mitigate the risk of fire due to the effects of arc fault currents.
It also addressed how electrical installations can provide the required level of service and safety for the lowest electrical consumption. It covered cover several energy efficient areas, such as electric vehicles, lighting, metering, cable losses, transformer losses, power factor correction and harmonics.
2022 and 2024
A second amendment to BS 7671:2018 was published in 2022 and introduced major safety and documentation updates. It included new or strengthened requirements for AFDDs in higher risk residential buildings, expanded use of surge protection devices, improved fire safety design documentation and the addition of a new chapter covering prosumer installations such as those with local generation and energy storage.
In 2024, BS 7671:2018+A3:2024 clarified the selection of protective devices in installations with bidirectional power flow, common in systems with PV, batteries and EV infrastructure. It required electrical contractors to consider whether devices are unidirectional or bidirectional, ensuring correct operation and safety in modern electrical installations.
2026
The fourth amendment – BS 7671:2018+A4:2026 – will include a new chapter on stationary secondary batteries used for storing and supplying electrical energy within installations, as well as a new section addressing functional earthing and functional equipotential bonding for information and communication technology (ICT) equipment and systems. The amendment is also set to introduce a dedicated section on power over Ethernet (PoE).
Section 710, which covers medical locations, has undergone extensive revision. Notably, it now includes a schedule of test results for recording the resistance of supplementary protective equipotential bonding conductors, providing clearer guidance for ensuring safety in medical electrical installations.
Mark Coles, Head of Technical Regulations at the IET, stated: “BS 7671:2018+A4:2026 continues the thread of embracing new technologies. The inclusion of a new section on stationary secondary batteries is an exciting step into the future of renewable sources of energy and their integration into our lives.”
Contributors
Rob Shepherd (author)
Rob is Consulting Editor for InstallerELECTRIC. He is a well-respected journalist with a strong history in the electrical sector.
