18th Edition: A brief recap

The new year brings new wiring regulations. Without these vital changes, you’re still not fully compliant.

With the six-month 17th-Edition cross-over period over, and the 18th Edition now firmly in place, it’s crucial that you achieve full compliance for any new installation work. We’re only several weeks into the new year, but with Christmas behind us, we look at what you need to know in 2019…

Arc Fault Detection Devices 18th Edition: A brief recap

AFDDs work by detecting a fault at a very early stage, but they are still only a recommendation at this stage, which leaves most contractors in a very grey area. This new regulation has been brought in to mitigate the risk of fire because of arc fault currents. New circuits now may require an AFDD to mitigate the risk of fire in AC final circuits of a fixed installation and protect against these arc faults.

RCD Protection

Now, all AC sockets that are rated up to 32A will require RCD protection, as opposed to just 20A in the 17th Edition. This regulation is designed to prevent electrical shocks to the installer working on live AC socket outlets. It is now vital that you understand which type of RCD to use.

Metal cable supports 

In the 17th Edition, only wiring systems located at fire escape route were required to be supported against premature collapse in the event of fire. However, this now applies throughout the entire installation, where all wiring must have metallic clip supports.


As you are aware, isolation is vital to carry out your work on, or in the vicinity of, parts that are normally live, without the risk of injury or death from electric shock or burns. In the new wiring regulations, every circuit and installation must be provided with a method of isolation from the supply. The isolation device should also be provided with a method to prevent unintentional or inadvertent reinstating. Remember, semiconductor devices can’t be used as isolating devices.

Energy efficiency

A completely new part of the 18th Edition surrounds energy efficiency and the key role it now plays. To most of you, the concept is nothing new, but with its inclusion in BS 7671, a good design will now need to take into consideration maximum demand, load profiles, power factor correction, location of equipment, controls, harmonics and cable sizing. This update is in place to achieve less impact on the environment, reduction of energy losses and less reactive maintenance.

For more on the 18th Edition, visit us in branch or refer to the news section on our website.