On the left side of image white text on a black background reads "Chauvin Arnoux Explain Energy Efficiency & the IET Wiring Regulations". On the right side of the image a Chauvin Arnoux PEL104 is monitoring an electrical installation.

Julian Grant of Chauvin Arnoux published an article in the January 2022 issue of Professional Electrician & Installer explaining an emerging focus of the 18th Edition IET Wiring Regulations: energy efficiency. As energy prices rise and we continue to work towards achieving net-zero emissions by 2050, ensuring electrical installations are energy efficient is more important than ever.[1]

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Why Should You Care About Energy Efficiency?

Chauvin Arnoux’s Julian Grant explains that Appendix 17 of the 18th Edition IET Wiring Regulations, which covers energy efficiency, is currently designated as ‘informative’. Unlike other sections of the Wiring Regulations, it is not compulsory and you do not have to adhere to the recommendations outlined therein. So, why should you care about it? Grant offers the following reasons:

1.) Energy Bills

Chauvin Arnoux’s 2020 white paper, Sound Advice on Saving Energy, revealed that studies conducted by the Carbon Trust showed that businesses could make savings of up to 20% a year simply through optimising energy efficiency. With fuel prices rising, businesses will want to keep energy bills as low as possible and, therefore, will want to ensure they are not squandering energy unnecessarily.

2.) Environmental Impact

Maximising energy efficiency reduces fuel consumption and subsequently greenhouse gas emissions. This isn’t just beneficial for the environment; it can help businesses to secure lucrative tenders which often request evidence of successful eco policies. Furthermore, Streamlined Energy and Carbon Reporting (SECR) regulations require qualifying businesses to disclose their energy use, carbon emissions, and energy efficiency actions alongside reference comparison metrics. As energy inefficiency can be detrimental to business, companies will want to be certain that their electrical installations and equipment are working optimally and in the most environmentally friendly capacity.

3.) Future-Proofing

Plans for future amendments to the Wiring Regulations involve expanding the section on energy efficiency which could include compulsory requirements. Understanding energy efficiency requirements and measures now will be advantageous should the IET make changes.

What Do the IET Wiring Regs Say?

As mentioned above all the recommendations contain within Appendix 17 are informative. However, familiarity with them is not only economically and environmentally beneficial but could be advantageous should they become compulsory. In his article, Julian Grant highlights that the appendix applies to new installations as well as modifications on existing systems and draws the reader’s attention to key points.

Load Profile

Grant explains that Appendix 17 begins by advising you to determine the load profile. This way you will know exactly when and where energy is being used.


To optimise energy efficiency, the IET Regs suggest using cables that are larger than the ones you might have chosen based solely on their current carrying capacity. This is because it will reduce losses in the cables while helping to ensure that loads are supplied at the correct voltage for efficient operation.

Load Arrangement

Another consideration touched upon in Appendix 17 is whether the loads can be re-arranged to improve energy efficiency. For example:

  • Can they be positioned to minimise the length of the cable runs?
  • Can non-essential loads be grouped so that they can be turned off to reduce peak demand?
  • Can loads be arranged to enable automatic control of some groups? For example, lighting can be controlled using light sensors, ensuring that they are only switched on when needed. Grant points out that the appendix specifically mentions “solutions for lighting control can increase energy efficiency by more than 50%”.

Power Factor

Appendix 17 advises that in many cases it is preferable to provide power factor correction for individual loads at local distribution boards rather than provide overall correction for the entire installation at the main distribution board.

Motors & VFDs

Energy savings can be made by installing the latest high-efficiency motors and/or variable speed drives in place of fixed speed starters.

Measuring & Monitoring

The final point that Julian Grant draws the reader’s attention to is the emphasis on measuring and monitoring. He quotes from the 18th Edition IET Wiring Regulations Appendix 17:

“[P]rovision must be made to allow the measurement and recording of energy consumption throughput major parts of the installation […] to achieve a design capable of delivering a high level of energy efficiency, all energy assumption data must be taken into account.”

How Will This Affect You?

There are multiple ways that optimising energy efficiency will affect you and others positively. As a private individual, ensuring energy efficiency works to reduce both your energy bills and carbon footprint. Businesses can benefit from this too; moreover, effective eco policies can help them to win lucrative contracts. Contractors and electricians may also find that a focus on energy efficiency provides profitable opportunities to sell more equipment and services.

Further Information

At PASS we offer an extensive range of IET guide books, City & Guilds 18th Edition training courses, and Chauvin Arnoux products including portable energy loggers. For further help and advice regarding any of these instruments, books, or courses, please contact our team on 01642 931 329 or via our online form.

To read Julian Grant’s article in full, please click here.

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[1] All information for this blog was gathered using the following sources: