18th Edition Update: How has it changed the way electrical installers are working?

29 January 2019

Ending months of anticipation, BS7671:2018, also known as the 18th Edition of the IET Wiring regulations finally came into effect on January 1st 2019.

This comes after a six-month adjustment period during which, all electrical professionals have been making the necessary changes. Six months ago, we looked at what may be the key changes facing electrical professionals; now, we thought we’d revisit this and see what’s really changed.

In line with the latest technology advances and updated technical data, the new regulations aim to make installations safer, as well as impact on energy efficiency.

So, what has changed?

There are many differences between the 17th and 18th Edition, from new and revised regulations to new chapters and restructured sections.

Energy Efficiency
In today’s environmentally conscious society, it’s important to acknowledge Appendix 17. In its first appearance, Appendix 17 makes recommendations for the design, construction and assembly of installations in order to make the use of electricity as efficient as possible. It’s an informative appendix, so it’s not a requirement, but it is a positive change intended to motivate electrical professionals to work with the environment in mind.

Providing Quality
Chapter 13 lays out that good workmanship and proper materials should be used in any installation and requires that designers and installers take account of manufacturers’ instructions. One example of this is that devices used in low voltage assemblies must only be those that have been declared suitable for that purpose by the manufacturer of the assembly. In other words, a professional should use manufacturer approved parts, aim not to mix brands and if in doubt, always ask the manufacturer to confirm compatibilities.

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Metal Cable Supports and other Non-Combustible Fixings
In the previous edition of the Wiring Regulations, only wiring systems on escape routes were required to have metal or non-combustible fixings. This has been updated and now encompasses all wiring throughout the installation, to help protect cables against collapse in the event of fire. Plastic cable clips are not permitted as a method of support in the event of fire.

Additional Protection by RCD
Residual Current Devices (RCDs) constantly monitor the electric current in the circuits they protect and trips the circuit if flow through an unintended path to earth is detected—such as a person. Previously, all sockets rated up to 20A required RCD protection, but this has been extended up to 32A, in an effort to reduce electric shocks to installers working with live AC socket outlets. We covered this point in our previous blog on the 18th Edition, and explain more about how the addition of RCDs in these applications are a potentially life-saving update.

Arc Fault Detection Devices
Chapter 53 of the Wiring Regulations has seen a major rewrite in this update and now includes new advice relating to where Arc Fault Detection Devises (AFDDs) are to be installed and located within the installation.

The Wiring Regulations stipulate protection against thermal effects that may occur as a result of arcing or burning, overcurrent, insulation faults, sparks, etc. AFDDs moderate fire risk in some circuits through early detection and isolation of arc faults. The use of AFDDs conforming to BS EN 62606, a requirement, is a recommended method for providing additional protection against fire caused by arc faults. The Wiring Regulations also advise taking into account the device manufacturer’s instructions.

If used, AFDDs should be placed at the origin of any circuit to be protected, for example, in the consumer unit or distribution board. AFDDs are especially important for accommodation buildings such as hotels and apartments; high fire risk locations or which are built from combustible materials such as wood; and locations which house irreplaceable items such as museums and galleries. 


Overall, the 18th Edition brings progress toward safer installation and safer spaces. New or revised processes now call for investments in new equipment, and perhaps further training. Now and going forward, electrical professionals will also have new opportunities to take on leading roles in the design process of buildings, to ensure the projects are fully compliant with new regulations.

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