Why AFDDs have made it into the 18th Edition of the Wiring Regulations

January 24th 2020

Paul Fisher, Managing Director of Electrium, discusses why AFDD technology has been included in the 18th Edition of the Wiring Regulations. 

Government statistics show that over 13,000 electrical fires occur each year. More than 7,500 of those are reported to be in electrical distribution, with the balance involving electrical appliances.

Even more shocking is the human cost – every year electrical fires cause numerous deaths and thousands of injuries. These statistics underline the importance of electrical safety and keeping up with the latest requirements and recommendations in terms of best practice and advancements in technology.

What’s new?

The fundamental principles in the latest 18th Edition wiring regulations are not new. The regulations require designers and installers to provide for the safety of people and property against dangers that may arise from the reasonable use of electrical installations. It states that the risk of injury may result from excessive temperatures that are likely to cause burns, fires etc. while also stating that risks of injury may arise from arcing or burning. Protection from such dangers is a requirement.

A significant new development for providing additional levels of this element of protection is the recommendation that Arc Fault Detection Devices (AFDDs) are installed to mitigate the risk of fire (from arc faults) in AC final circuits. This is referred to in Chapter 42 (section 421) which includes requirements to protect against fire from electrical equipment and states that harmful effects from heat or fire may be caused by insulation faults, arcs sparks and high temperature particles. AFDDs are viewed as a provider of additional protection.

While this is a new recommendation, it would be unwise for designers, installers and owner operators to ignore the regulator’s advice. Any intended departure from this recommendation should be carefully considered and justified in writing by the decision-maker. It should also be recorded on the electrical installation certificate and the alternative design must not result in a lower degree of safety than would otherwise be achieved by compliance with the 421.1.7 recommendation.

How do AFDDs work?

AFDDs monitor electrical circuits for unusual conditions that are indicative of a series or parallel arc and automatically trip the circuit when a dangerous electric arc is detected. Arc faults can arise from cable insulation faults, poorly made connections, crushed cables, frayed conductors, DIY mishaps, and daily deterioration of insulation materials. They create a build-up of heat that can ignite flammable materials and trigger a fire.

Arc faults aren’t easy to detect but AFDDs are extremely sensitive and can identify arc fault signatures. AFDDs are miniature, modular devices that are easily installed in consumer units. They can also be combined with MCB and RCD technology to provide arc fault protection in addition to overload, short circuit, earth leakage and electric shock protection on each circuit.

How is the industry responding?

Our research shows that electrical professionals are very familiar with AFDDs and recognise the benefit – 92% have heard of AFDDs and 71% agree that AFDDs could prevent fire, protect lives and property. Similarly, awareness of the latest regulations is also good – 88% of electrical professionals know that AFDDs are included in the 18th Edition.

There has, however, been a slow take-up to install AFDDs, with 90% of professionals yet to fit an AFDD. Some of the reasons for not using AFDDs show a lack of understanding of what is available in the market. 31% say that AFDDs take up too much space and aren’t practical to install.

The good news is that the latest models from Electrium are much smaller. Similarly, 33% say they’re too costly – yet the newest versions are also offer greater value for money because they actually incorporate three products – the MCB, RCD and AFDD – in a single module device.

Finally, some professionals say the demand is not there from homeowners. This isn’t surprising as amongst consumers, awareness is low. However, like many other safety issues, we strongly believe that it is the job of the industry to drive forward the adoption of AFDDs and promote best practice. Consumers may not be asking for them but you can be sure that when the benefits of the device are explained, they will be keen to see them installed.

Learn more about Arc Fault Detection Devices

Our 18th Edition area has tons of information on arc fault detection devices. Learn more here. 

Crabtree and Wylex, part of the Electrium family, both have single module AFDDs for your next install.

Choose from Crabtree or Wylex and start your journey. 

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