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Circuit training

May 2018 18th Edition, General | Comments Off on Circuit training
Circuit training

As electrical technologies evolve, one thing remains constant – the vital importance of circuit protection and its critical role in electrical safety. With the 18th Edition just around the corner, MK Electric head of marketing looks at its past, present and future

It may seem hard to believe, but it is less than 150 years since the first public experimental supply of electricity was provided to the streets of Godalming in 1881. A year later, the 1st Edition of the Institution of Electrical Engineers (IEE, later to become part of the IET) wiring regulations, entitled ‘Rules and Regulations for the prevention of Fire Risks Arising from Electric Lighting’, was published.

This simple four-page document was far removed from the comprehensive regulations of today. At the time of publication, there was no formal inspection body, and no way of knowing if the outlined regulations were actually being adhered to in practice. At this stage, circuit protection was in its earliest phase, taking the form of a re-wirable fuse. These are no longer advocated in the regulations following significant improvements in life safety de-vices available.

So, as we approach the latest update to the wiring regulations, 136 years since the first guidelines were published, how much has changed, and what next for domestic circuit pro-tection?

As a manufacturer that prides itself on reflecting the changing needs of its customers, MK Electric keeps a close eye on the changing landscape of domestic circuit protection. Below, we take a look at the biggest shifts of recent years and what the 18th Edition is likely to bring.

17th Edition

The 17th Edition wiring regulations BS 7671 came into force on 30 June 2008, when the previous 2001 version was withdrawn and it became the required standard for all new in-stallations.

This set of regulations contained a number of updates pertaining to circuit protection, and most prominently, a call for more extensive provision of RCD (residual current device) for domestic and non-domestic dwellings.

This edition mandated that, in most circumstances, a consumer unit would be required to have increased protection, using multiple RCDs or RCBOs. The increased use of these life-saving devices represented a new level of circuit protection safety, improving on previous standards.

A few years later, circuit protection would evolve again with the publication of BS 7671: 2008(2015) – Amendment 3 to the 17th Edition of the IET wiring regulations. Amendment 3 was in part developed as a response to a report from BEAMA that identified the primary root-cause of consumer unit fires as loose connections. This was bolstered by research from the London Fire Brigade (LFB) that revealed an increase in fires involving consumer units, raising concerns around the flammability of consumer unit enclosures.

Alongside the BEAMA working groups that were instrumental in developing Amendment 3, the LFB, Electrical Safety First and other industry organisations played a major role in lobby-ing for the edits to Amendment 3 to reduce the risk of residential fires and consequently improve personal safety.

This collaborative work resulted in enhanced fire risk protection within Amendment 3, re-quiring switchgear assemblies – including consumer units – to have their enclosures made from a suitable non-combustible material, or be installed in a cabinet or enclosure com-prised from a suitable non-combustible material, for example steel.

In practice, this change meant a move from the plastic consumer units, which had become commonplace for their cost-effectiveness and aesthetic appeal, to metal. Until this point, the wiring regulations had never stipulated a material for enclosure construction, and Amendment 3’s requirement for non-corrosive material represented a major advancement in terms of modern circuit protection.

MK Electric responded to this change by releasing a full range of metal Sentry consumer units, thereby supporting contractors as they made the switch by offering compliant, high-quality units that contractors could trust to meet regulations and protect customers.

18th Edition

The 18th Edition is due to be published in July 2018, with the regulations coming into full effect in January 2019.

While we will have to wait until 2 July to get the full picture, we do know that there will be a recommendation for the installation of arc fault detection devices (AFDDs).

AFDDs are designed to mitigate the risk of fire in the AC final circuits of a fixed installation due to the effects of arc fault current – an important consideration given the number of fires linked to electrical distribution. The numbers around this are far from negligible. In fact, UK fire statistics for 2013-14 identified that around 12% of electrical fires start within the electrical distribution system of an installation (wiring, cables, plugs).

Essentially, AFDDs are able to detect dangerous arc faults, which MCBs and RCDs cannot identify, further increasing the safety that domestic circuit protection can offer, and closing the gap on the risk of fires. This means they offer enhanced safety and defence against fire outbreak, and could likely reduce the above accidental fires.

AFDDs are already common in certain parts of the world, especially those that have histori-cally utilised timber-framed buildings. North America, for example, has mandated AFDDs for around 20 years, while much of northern Europe has been using them for a few years.

It is important to note that the use of AFDDs is expected to be an advisory rather than a mandatory requirement. Despite this, specifiers and designers for developments such as social housing, sheltered accommodation and university halls, where the occupier doesn’t have any decision-making powers over the safety devices used, could begin to adopt AFDDs as a matter of course, as part of their duty of care to users and residents.

In terms of other key circuit protection changes, contractors should look out for Section 536: Co-ordination of electrical equipment for protection, isolation, switching and control. The term ‘discrimination’ has been replaced by ‘selectivity’, where selectivity is the ability of a protective device to operate in preference to another protective device in a series.
Circuit protection has come a long way over the last century as manufacturers and contrac-tors strive to create ever safer environments.
The 18th Edition is just the latest update to circuit protection regulations – there will doubt-less be further improvements and innovations on the horizon, and it is important contrac-tors stay abreast of changes.

Following its rapid reaction to the changes of Amendment 3, MK Electric will continue to update its range to meet the latest regulations and the needs of contractors, offering flexi-bility, support and peace of mind.