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AFDD
a variety of potential faults, nor should lighting circuits be on individually protected circuits, so as to remain on at all times and not plunge people into darkness when other circuits are faulty. The simple way to comply with this regulation is to use RCBOs (and for more information see Chapter 31, Division of the Installation).
Protection against the risk of fire The 18th Edition recognises that risk of injury may result from arcing or burning (131.1), and so includes requirements for installations to be so arranged that the risk of ignition of flammable materials due to high temperature or electric arc is minimized, and requires people, livestock and property to be protected against the risk of burns (Chapter 13). Electrical fires caused by dangerous arc faults
typically occur at loose connections, poor terminations, or in impacted and damaged leads
Wylex mini-RCBO
and cables, or through old, weak and failing insulation. AFDDs (Arc fault Detection Devices) can decrease the likelihood of electrical fires from these conditions by detecting the arcing conditions before the overheating and ignition of flammable materials. AFDDs detect arc faults that cannot be
detected by RCDs or MCBs. These new devices use digital technology to provide additional protection against fires caused by arcs in AC 230V final circuits, making them a must-have for new installations.
Manufacturer approved parts Another new regulation, 536.4.203, states that only devices and components that have been declared suitable for purpose by the manufacturer of the assembly can be used in in low voltage assemblies, such as consumer units. Or put another way: only use manufacturer approved parts, don’t mix brands of devices or
control items. Using unapproved parts will invalidate manufacturer guarantees and may result in an unsafe installation.
A bitesize brief Designers and installers should obtain their own copy of BS7671:2018 and follow the requirements and recommendations in the 18th Edition of the IET Wiring Regulations, but to understand these requirements in more detail, Wylex has created a Bitesize look at some of the new content. The guide has been produced in order to help simplify and emphasise certain key points.
The bitesize document includes requirements
for overvoltage protection, prevention of unwanted tripping of RCDs and the use of AFDDs - to name a few. The “Bitesized Look at Some New Regulations” is available for download at:
electrium.co.uk/18th-edition
AFDDs detect arc faults that cannot be detected by RCDs or MCBs. These new devices use digital technology to provide additional protection against fires caused by arcs in AC 230V final circuits, making them a must-have for new installations.
18 | electrical wholesalerDecember 2018
ewnews.co.uk
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