RC Electrical is now trained in these regulations. If this is something that you are interested in, contact us to find out more information about the new regulations and how this can effect your electrics.

After months of anticipation and speculation has come to an end as the Edition of the 18th IET wiring regulations has now been published throughout the UK. This means it will be effective from January 1st 2019 to all electricians. With the 18th Edition, there will be many revised regulations, restructured sections and new chapters available. RC Electrical have been keeping themselves in the loop with the new rules that come with the 18th Edition. They are now trained in these regulations.

The new Regulations apply to the design, erection and verification of electrical installations. This also includes additions and alterations to existing installations. This means that existing installations that have been installed in accordance with earlier editions of the Regulations may not comply, but we will inform you when this is applicable.

These are the chapter headlines available in the book:

These chapter titles are taken from www.electrium.co.uk


Extended Scope

The scope has been extended to include an extra category (section 730 catering for electrical shore connections & inland navigation vessels).  Section 730 contains the particular requirements for this added special location.

Chapter Changes

Chapter 46 is new and Chapter 53 has been rewritten. Part 6 is restructured & the regulations for inspection & testing move to new chapters and get new regulation numbers.


There are several new definitions, and a few existing definitions that have been amended. For example, “Departure” is a new definition.

Departure is explained as an intentional decision to not fully comply with BS7671.This must be accompanied by a declaration from the designer that the safety levels achieved are not less than full compliance with BS7671 would provide.

Energy Efficiency

A new appendix on energy efficiency is included within the 18th edition. Appendix 17 makes recommendations for the design construction & assembly of the installation for optimising efficiencies in the use of electricity.

Only Use Approved Parts

Devices & components used in low voltage assemblies e.g. Consumer Units, Distribution Boards etc. shall only be those that have been declared suitable for that purpose by the manufacturer of the assembly.

If in doubt ask the manufacturer of the assembly to confirm compatibilities.

Note; if a deviation from manufacturer instructions is introduced then the person introducing the deviation becomes the manufacturer.

Arc Fault Detection Devices

AFDDs have been included in Chapter 42. These devices provide additional protection against fires that are caused by arc faults in AC final circuits.

Arc fault detection devices (when used) should be installed at the origin of each final circuit that is are being protected, AFDDS should be installed in consumer units and/ or distribution boards.

Appendix 6

In the schedule of inspections, under the section dealing with consumer units & distribution boards there is a reference to check for the AFDD six monthly test notice, similar to the requirements for RCDs & RCBOs.

Also in the schedule of test results form there is a new tick box for AFDDs which allows the installer to record operation of the manual test button on the AFDDs, again this is similar to RCDs & RCBOs.

Surge Protection

Within the 17th Edition of the Wiring Regulations, the requirements of surge protection were determined through risk assessment methods. Now, overvoltage protection is required in certain circumstances.

For example, where there is risk of serious injury or of loss of life,  where many co-located people are affected, where there is an interruption to public services, or commercial / industrial activity. Other requirements are contained in 443.4.

For circumstances where overvoltage protection is not required, a risk assessment can be carried out. If a risk assessment is not carried out, overvoltage protection must be provided.

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