Feature Circuit Protection
There’s safety in the standards T
There have been few electrical manufacturers that have developed their products in response to the amendments to BS and EN standards for RCDs that were introduced in 2012. Here, Allan Boutall, design manager at GreenBrook, highlights why they are so important in underpinning electrical safety Important updates
he core technology at the heart of residual current devices (RCDs) performs the same task today as it did more than 35 years ago when RCDs first became commonplace. However, the RCD products themselves have developed significantly in the interim. Over the years, standards of safety, durability and aesthetics have all improved, driven partly by market forces and the need to stay ahead of the competition, and partly by revisions to BS and EN standards focused on driving improvements in safety and quality. However, despite this, recent research by the Electrical Safety Council (ESC) has revealed that less than 50% of UK homes are protected by any kind of RCD, thus presenting a significant risk of elec- trical injury, fatality or a house fire due to an electrical fault. The ESC also found that there is a lackadaisical approach to good electrical safety behaviours in the home, with many of those surveyed admitting to leaving equipment unat- tended or unventilated.
Updates improve product perfor- mance and provide the end user with confidence of consistently high stan- dards so should be an immediate cue to invest in product development. Let us take, as an example, one of the key changes introduced in the most recent revisions to BS EN 61543:1995 - the addition of new EMC (electro- mechanical compatibility) require- ments. Designed to ensure that RCDs are robust and resistant to high electrical spikes and are neither susceptible to electro-mechanical interference, nor a potential source of electro-magnetic interference, EMC compliance requires numerous tests including fast, transient bursts of 4kV at repetitive frequency, 2.5kHz tests and high surge current tests. Only by investing in product develop- ment and stringent testing, carried out by a specialist EMC laboratory, can man- ufacturers comply with the standard. While this may be a major outlay upfront, it is also an investment in cus- tomer confidence and product quality.
Above: Allan Boutall, design manager at GreenBrook
solution for each installation. EMC requirements are just one exam- ple of updates to BS EN standards for RCDs that have not seen widespread implementation across the market- place. Others include the latest BS 1363-4 specification which requires that RCD spur units have an adjustable cable clamp to provide retention of cable of any diameter ranging from OD 4.6mm to 10.4mm.
Left: revisions to BS and EN standards are focused on driving improvements in safety and quality
This not only improves flexibility of installation for the contractor but could impact on safety for the end user because it will ensure that the cable is retained and secure and will not come lose. Conforming to this change was a simple matter of product development for GreenBrook and should be both a ‘must have’ product development for the manufacturer, and a ‘must see’ product feature for the specifier. Some manufacturers are not as aware as they could be of the latest BS EN stan- dards requirements for RCDs. As a result, those specifying RCDs must be methodical in understanding current BS EN standards and demanding proof of compliance from their suppliers. If in doubt, the best advice is to ensure that you always purchase RCDs from BEAMA member manufacturers who will always have the inside track on the very latest standards and developments.
This has led to the launch of the
ESC’s ‘Plug in to Safety’ campaign, which GreenBrook is supporting. Just 250mA of current leaking through a human body for 200 milliseconds can be fatal and contractors regularly sug- gest RCDs as cheap and effective pro- tection for their domestic customers. However, not all RCDs on the market actually comply with the latest BS EN standards. While the prolifera- tion of counterfeit products entering the UK market is being tackled with some success by the British Electrotechnical and Allied Manufacturers Association (BEAMA’s) anti-counterfeiting campaign, lack of awareness about the requirements of the latest standard for RCDs means that there are many products being sold that simply do not comply.
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How to tackle the problem? Most reputable RCD manufacturers are members of BEAMA, so they have recog- nised that failure to comply with stan- dards has become an increasingly important issue in the industry and it’s one which they are committed to help- ing to address. Indeed, BEAMA, with the support of its members, is now in the process of developing a campaign that aims to tackle this issue by raising awareness of the dangers of buying and installing non-compliant products amongst both electrical wholesalers and contractors. BEAMA’s comprehensive guide to RCDs, which was put together to coincide with the introduction of the 17th Edition of the Wiring Regulations, also provides an important reference text for specifiers and contractors to help ensure they use the most appropriate
Plugging in to change Ultimately, one would hope that more and more RCD product lines will even- tually become fully compliant. While many installations these days rely on RCD protection for circuits or consumer boards, the 17th Edition of the Wiring Regulations clearly recommends that RCDs should also be used on sockets, so ensuring that those socket-based devices have been designed in line with the current standard and have been thoroughly tested to verify compliance is essential. It is unfortunate that so many manufacturers seem to view the latest requirements as onerous obliga- tions rather than an opportunity to enhance product quality and end user safety, but an insistence of quality and an emphasis on safety at contractor level will help to drive change.
Greenbrook
www.greenbrook.co.uk T: 01279 772 700
Enter 210 OCTOBER 2013 Electrical Engineering
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