The 18th Edition of BS7671, the UK’s standard for electrical wiring installation, was released in 2018 and is now fully in force. As a general rule, anyone working as an electrician in the United Kingdom should have comprehensive knowledge of the most recent edition of BS7671. This is not a legal requirement, but as this standard is recognised as the most thorough and is published by the UK’s highest governing body in terms of electrical installation, The Institution of Engineering and Technology, it is seen as a mandatory resource.
The 18th edition of BS7671 officially came into force on January 1st, 2019 and superseded the 17th edition of the regulations, which were last updated in 2015. As of now, they are the standard for electrical installation in the United Kingdom.
The key differences are mainly driven by technical advances and are briefly described below:
AFDDs are one of the most discussed additions to the regulations, and they have been added as a recommendation. These circuit breaker devices use a microprocessor to detect an electric arc in the circuit, which could pose a significant fire risk. The regulations recommend the installation of one of these devices in consumer units and at distribution boards. Such devices are still relatively new to the British market, but have been the standard in the US and Canada for several years now.
RCDs (residual current device) are potentially lifesaving devices designed to protect users and installers from electric shock. A 30ma RCD trips when 30ma of current is "missing." In some locations, a 30ma trip is the maximum allowable for personal protection, prevention of electrical shock injuries and the 18th edition recommends increasing use of them where they were previously deemed necessary. In previous additions, these devices were recommended for installation on sockets up to 20A, but in the new regulations, <30mA RCDs should be fitted on all sockets up to 32A unless a thorough risk assessment is carried out that finds the fitment unnecessary.
Another addition to the 18th edition regulations deals with energy efficiency which is something that numerous industry regulations are increasingly including. As we move to towards more efficient lives, and are encouraged to use less and less electricity there will naturally be a requirement to make electrical circuits as efficient as possible. In the new regulations, recommendations are made in terms of circuit designs and install.
Surge protection has been an important feature in the previous edition regulations, but the 18th Edition also brings with it a requirement to consider overvoltage protection. The guidance insists that a risk assessment is carried out to determine if this is required, with a variety of factors playing into this. Where there would be significant injury or loss of life, or where public services may be interrupted, overvoltage protection should be installed. If a risk assessment is not carried out for whatever reason, then again, overvoltage protection is a requirement.
Metal Cable Supports
Regulations previously stated that wiring found in fire escape routes should be supported by metal clips to protect against collapse in the event of a fire. This has now been revised, and the regulations suggest that all wiring installations will need support going forward, with an adequate number being constructed from metal.
Certification and Reporting
Model forms have also been revised and the new regulations now require the use of 18th Edition certification or reports. These include Electrical Installation Certificates, Minor Electrical Installation Works Certificates and Electrical installation condition reports.