One key change: one huge impact

Energy Efficiency might not cover your safety, but this new 18th Edition regulation is one hot topic.

Energy Efficiency in the 18th Edition

The IET Wiring Regulations are primarily concerned with the safety of electrical installations, but energy efficiency has taken a firm place in Part 8, Section 801 of the 18th Edition. As you are aware, energy efficiency has been part of building design for years, particularly in Europe.

However, In the UK, these solutions were usually implemented at the discretion of the engineer, and often not for environmental reasons but rather to reduce equipment demands and sizes.

Therefore, the reason behind this new addition to the wiring regulations is the increasing importance of having energy efficient electrical installations.

What does it cover?

In the 17th Edition, the steps to be taken during the design process of an electrical installation followed the hierarchy of SAFETY – CAPACITY – RESILIENCE. In the 18th Edition, an extra step has now been added: SAFETY – CAPACITY – EFFICIENCY – RESILIENCE. Section 8 allows an installation to be specified as to how electrically efficient it is, not how it is operated. It gives guidance on all aspects of design and covers the following areas of installation:

  • Voltage measurement
  • Power factor correction measures
  • Power management system
  • Transformer efficiency
  • Load Profile
  • Motors
  • Consumer demand
  • Tariff structure
  • Data logging
  • Lighting
  • Wiring Systems
  • Location of main sub station
  • HVAC equipment
  • Power measurement
  • Renewable energy
  • Harmonic measurement

How does it affect me?

From a design and installation point of view, energy efficiency can be applied to all installers, whether that’s domestic, commercial or industrial. Therefore, it’s important to note that in the 18th Edition, the designer and installer both need to take responsibility for the efficiency of the electrical intake and distribution system efficiency, while also considering the control system effectiveness.

Benefits of these new energy-efficient solutions means you are now able to:

  • Lessen the impact on the environment
  • Reduce energy losses and energy costs
  • Use energy only when it is required and potentially only during off peak
  • Lessen unplanned maintenance due to damages caused by heat losses
  • Optimise the electrical system performance for life cycle


Another important area is the electric vehicle and whether the charging infrastructure that is being installed is being done safely and correctly.

For more advice and information on the 18th Edition changes, please refer to the news section on our website