Regulation Changes: 18th Edition Wiring Regulations due 1st July 2018

With the 18th Edition to the Wiring Regulations only 12 months away (it’s due to publish 1st July 2018). Andrews Electrical ltd take a look at what is being discussed at committee level now and what changes may be included in what will be BS 7671:2018. (BS 7671: the 18th Edition report)


Protection against over voltages

To summarise Clause 443 is likely to be significantly revised based on the recently published IEC and CENELEC standard. However, the exact requirements will have to be agreed by the UK national committee. If BS 7671 follows the IEC and CENELEC standard the AQ criteria for determining if protection against transient overvoltage is needed would no longer be included in BS 7671. Instead, protection against transient overvoltage would have to be provided where the consequence caused by overvoltage affects:

  • Human life, e.g. safety services, medical care facilities
  • Public services and cultural heritage, e.g. loss of public services, IT centres, museums
  • Commercial or industrial activity, such as hotels, banks, industries, commercial markets, farms

Protection against Fire

Protection against fire resulting from the electrical installation and the use of the electrical installation has been necessary ever since electricity was first introduced into buildings. The requirements for the protection of persons, livestock and property against fire caused by electrical equipment, against burns and overheating and for including precautions where particular risks of fire exist are contained in chapter 42.

RCDs can reduce the likelihood of fires associated with earth faults. However, whilst RCDs can detect earth faults they aren’t able to reduce the risk of electrical fire due to series or parallel arcing between live conductors because there is no leakage current to earth. Details will be included in BS 7671:2018 for the installation of arc fault detection devices (AFDDs) to mitigate the risk of fire in final circuits of a fixed installation due to the effect of arc fault currents.

Changes to Section 753

The scope of Section 753 has been extended to apply to embedded electric heating systems for surface heating. The designer will be required to provide appropriate information about approved substances in the surroundings of the heating units.

New section – energy efficiency

The worldwide need to reduce the consumption of energy means that we have to consider how electrical installations can provide the required level of service and safety for the lowest electrical consumption. The draft proposals enable a client to specify the level of energy efficiency measures applied to an electrical installation. Installations can also be awarded points for energy efficiency performance levels, for example, transformer efficiency.

Andrews Electrical Ltd has used information for this article researched from The Institution of Engineering and Technology (IET)