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Issue18 | Autumn 2010 | ÂŁ5.00
Killer at the gate ESC highlights the dangers of electrically-powered gates
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WELCOME While we have an excellent record for safety of fixed electrical installations in the UK, having no controls in place for people undertaking certain electrical work could, particularly in difficult economic times, see an explosion in DIY. This would negate the efforts of everyone over recent years to improve the safety of electrical installations in people’s homes across the UK.
o a new government is now in full swing and looking at how it can reduce the budget deficit. The level of cuts is potentially deep and just recently a massive 40% reduction of spend across government departments was being mooted; let’s hope the reality is less harsh for everyone’s sake.
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Part of the government’s push to reduce costs is to ease the burden of regulation on business, and it is anticipated that many established regulations, including the Building Regulations, will at some point come under the government’s spotlight. There are some that would welcome the review of regulations, particularly if it saw the end of Approved Document P, although it is the Electrical Safety Council’s view that Part P is having a positive effect and that its removal would be detrimental to electrical safety.
the annual report, which this year has a different look and feel. As a charity we have a duty to report on the impact, or otherwise, of our campaigns in respect of how they helped the beneficiaries of the Charity. The report is available via our website, so please download a copy.
Therefore it was with some concern that we learnt through correspondence from the wife of a Part P registered installer that some registered electricians are willing to notify work on behalf of others, without even seeing the work that was undertaken. This practice could have devastating consequences for the customer should the work be defective. It will also make the firm notifying the work liable should anything happen and the firm also risks being prosecuted because it will have taken responsibility under the requirements of the Building Regulations. While we have raised the matter with the scheme operators, we would ask that if you are approached to notify work on behalf of someone else, you point them in the direction of the local building control department or, better still, suggest they register with one of the schemes. After all, if you have made the decision to invest in your profession, why shouldn’t they? Our year-end review occurred at the end of March and we have been busy developing
As always, we would welcome feedback on Switched On, to help us improve the content. Email feedback@esc.org.uk Phil Buckle Director General
FROM THE EDITOR…
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een readers of Switched On will notice that we’ve introduced a few changes to the magazine for this issue. We’ve listened to your feedback about how you use the magazine and what you would like to see in it and made some improvements.
to air their views on any the issues raised in published articles. The new Letters column page 6 is there for you as a valuable feedback mechanism and I urge you to write in with any concerns, comments or criticism.
We’ve made Switched On easier to navigate around by introducing clear and simple signposting to help you distinguish from news coverage, features and technical articles. We’ve also given readers a platform
I hope that you like the improvements we’ve made. Happy reading. Andrew Brister Editor andrewbrister@ymail.com
SwitchedOn Issue 18 - Autumn 2010
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Council partners with Trading Standards - see page 9
issue 18 Autumn 2010
switchedon your insight into the electrical safety industry
news
technical
features
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Have you ever been asked...
10 Electric shock is not the only
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Spotlight on…BASEC and cable safety
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From the editor… Also, Welcome
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News in brief
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Plug into Safety campaign sparks the media’s attention
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Progress of investigation into in-service reliability of RCDs
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Letters Also, Annual consumer survey
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ESC publishes two leaflets on downlighters Also, ESC schedule of events
Assessing the general characteristics of a domestic electrical installation
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Private tenants at increased risk of electric shock
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Investigation into overloading of four-way extension leads
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Exploring the EU Injury Database (IDB) for consumer product risk categorisation
danger from electricity
12 Homes made safe by ESC grants scheme
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Essential Guide to the Wiring Regulations ESC partners with Trading Standards
SwitchedOn Issue 18 - Autumn 2010
Published by: The Electrical Safety Council Unit 1.10, Canterbury Court, Kennington Park Business Centre, 1 - 3 Brixton Road, London SW9 6DE www.esc.org.uk www.eschub.org.uk www.twothirtyvolts.org.uk www.switchedonkids.org.uk Tel: 0870 040 0561 Fax: 0870 040 0560 email: switchedon@esc.org.uk
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news IN BRIEF Launch of the ESC Hub Work is progressing on the development of the ESC Hub. It will bring together the Electrical Safety Council’s considerable guidance for industry and provide a central reference source for electrical installers. Currently The Hub only provides access to the Essential Guide, with the remainder of the Council’s industry publications on its main website at www.esc.org.uk. However, in order to provide clearer definition between the ESC’s industry and consumer communications, the Council is moving the technical guidance and industry communications to The Hub www.eschub.org.uk. The Hub will grow to include the full range of Best Practice Guides, technical articles, back copies of Switched On magazine and a user-friendly online version of each current issue. It will be updated regularly with industry news and events and the topics raised via the industry forum will also be posted regularly. Users will be able to register to receive regular news and articles direct from the Electrical Safety Council. Look out for the launch at the end of the year.
International Product Safety symposium takes shape As reported in the summer issue of Switched On, the International Consumer Product Health and Safety Organisation (ICPHSO) symposium in association with the Electrical Safety Council is to take place in London on 29 – 30 November. The 2010 symposium promises to be outstanding and an event not to be missed. It will bring together the electrical product safety community to share information and to formulate workable solutions for improving the safety of electrical products in a truly globalised marketplace. The Council is taking the lead role in the plenary session on counterfeiting and will be presenting at other plenary sessions and breakout sessions, as well as being an exhibitor at the event.
The ESC is warning people in Glasgow about the dangers of buying counterfeit electrical goods, following reports from Glasgow City Council that hundreds of counterfeit GHD hair straighteners are on sale in the city.
By the time this issue of Switched On is distributed, two new Best Practice Guides should have been published: Best Practice Guide No 7 Test instruments for electrical installations: Accuracy and consistency Best Practice Guide No 8 Selection and use of plug-in socket-outlet test devices
To report counterfeit goods contact Consumer Direct on 08454 04 05 06.
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If you have any suggestions for further Best Practice Guides, please send them to bpg@esc.org.uk
For further information on the symposium and updates on the event programme keep an eye on our website www.esc.org.uk .
Best Practice Guides - an update
Further information or advice can be found at www.esc.org.uk or call the ESC helpline on 0870 040 0561.
Work on updating the published Best Practice Guides on microgeneration (No 3), and domestic electrical installation condition reporting (No 4) is now expected to start in the autumn.
Please note that registrations are as always limited, so to be sure of your place visit the ICPHSO website www.icphso.org.
Electrical safety threat in Glasgow
“With 44% of all accidental fires in UK homes arising from faults or misuse of electrical goods, we are very concerned for the safety of anyone in Glasgow who has bought and is using any sort of counterfeit electrical goods”, says Steve Curtler, product safety manager at the ESC.
Until around November, all ESC Best Practice Guides can continue to be viewed at, or downloaded free of charge from, the ‘Business and Community’ section of the main ESC website www.esc.org.uk. After that, all the information intended for the electrical industry will be migrated to the new ‘Electrical Information Hub’ at www.eschub.org.uk
Both guides have been developed by a Working Group comprising representatives from the following organisations:
Amendment 1 to BS 7671: 2008 By the time this issue of Switched On is distributed, the closing date for comments on the Draft for Public Comment of the proposed first amendment to BS 7671: 2008 will have passed. The committee responsible for the technical content of the standard, together with its four panels, will have begun to consider all the comments received.
BSI • City & Guilds • Electrical Safety Council • GAMBICA Association • ECA • ELECSA • NAPIT • NICEIC • SELECT
BS 7671: 2008 incorporating Amendment No 1 is expected to be published on 1 July 2011 and, following a six-month transition period, all installations designed after 31 December 2011 will have to comply.
The HSE has a particular interest in the guidance on the selection and use of socketoutlet test devices, as this had been an area of concern to it for some time. It is also hoped that the Institution of Engineering and Technology will add its support to both guides.
The amendments will not be published as a separate document, but will be incorporated in a new full version of the regulations which, for the first time, will be referred to as the ‘IET Wiring Regulations’. In accordance with tradition, the first amendment will have a green cover.
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news
PLUG INTO SAFETY CAMPAIGN SPARKS THE MEDIA’S ATTENTION he first wave of the ESC’s five-year flagship campaign – Plug into Safety – has generated strong media interest, with coverage across the UK on local radio and television as well as national and regional press.
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Plug into Safety, which aims to promote awareness of the benefits of RCD protection to consumers, was launched during May Bank Holiday – a particularly active time for both DIY and gardening enthusiasts, who are the initial focus of the campaign. In the UK one person a week dies from an electrical accident in the home and research indicates that gardeners and DIYers are most at risk of electric shock or injury. This is due to their use of hand-held power tools which have cables or leads that can easily be cut through and which are often operated in damp or wet conditions. In these circumstances particularly, the use of an RCD can quite simply be a lifesaver. Despite the safety benefits that RCDs offer, ESC research found that almost 13 million homes in the UK do not have adequate RCD protection; and almost 70% of people are unaware of what they are. The Plug into Safety launch was fronted by the well-known celebrity builder, Tommy Walsh, but a number of ESC staff also took to the airwaves to publicise the campaign. Phil Buckle, director general of the ESC, undertook a regional radio blitz and was interviewed by Sky News; and Gary Gundry, one of the ESC’s senior engineers, featured on a BBC London television programme.
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In addition to coverage in a range of trade press, the Plug into Safety campaign also featured in several national newspapers including The Guardian, The Sunday Mirror and The Mail on Sunday as well as a host of regional titles. Coverage is continuing to filter through into various media channels, including online sites, and more features are in the pipeline over the coming months. The electrical industry has been extremely supportive of the campaign and the ESC is working with key stakeholders including the fire service, housing providers, government and electricians in order to take RCDs mainstream. For example, one way in which the ESC is engaging with electricians is through a free toolkit which will provide them with the key information needed to inform consumers about the importance of using RCD protection (see box). Through collaboration with our partners, the ESC aims to increase awareness of RCDs in much the same way that smoke alarms were promoted by the government in its ‘Fire Kills’ campaign - the campaign persuaded 70% more households to use the safety device in their homes. “The flagship campaign is off to a great start,” says Cherry Read, head of communications and campaigns at the ESC. “We hope, that by focusing on an issue with such a fundamental and clear safety message, we will really be able to make a difference to people’s safety.”
Toolkits for electricians Along with the consumer materials that will be available at point of sale with retail partners, the ESC is providing packs to electricians to help them engage with their customers and convey the benefits of having RCD protection in their homes. The pack will include 50 leaflets and a business card that electricians can leave with their customers. With support from the Electrical Safety Council, it is hoped that this will enable more electricians to help their customers understand the benefits of RCDs. The packs are available from wholesalers and industry bodies. To find out more, email plugintosafety@esc.org.uk
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letters What about RCD sockets? I was delighted to read about the launch of the ESC’s Plug Into Safety campaign in the last issue of Switched On magazine: as the company that first launched RCD adaptors in the UK and has pioneered RCD use for the past 35 years, it’s a campaign that we at GreenBrook wholeheartedly support. However, this campaign is about educating the marketplace and ensuring that both those that specify RCDs and those that use them in the home are familiar with all the products available so that they can select the best solution for their needs. What I was left asking myself after I’d read your article was how can this education campaign hope to succeed if many of the most popular and widely-used RCD product types are not even mentioned in the media coverage? While the article discussed the importance of consumer board units and portable adaptors, no mention was made at all of RCD sockets or fused spurs, both of which are best sellers. Leaving out these product types from any discussion fails to educate the marketplace and, ultimately, will fail to increase levels of safety. The stark facts are that almost 10% of all fires in the UK are caused by electrical faults of one kind or another and that equates to just over 20,000 fires every year! What’s more, 50% of UK homes still do not have RCD protection (that’s 13 million homes), all of which highlights the need for better understanding of the role of RCD protection and the varied forms it can take. Obviously, in the commercial world everyone wants to sell the products that will help them develop market share, but the issues at stake here are more than simply commercial – this is a matter of life and death. That’s why my recent presentation on RCDs to the Electrical Distributors’ Association (EDA) covered product types that GreenBrook doesn’t even sell and why I would urge anyone else involved in the manufacture, promotion or sale of RCDs to focus on a clear, representative safety message, regardless of their own commercial interests. It’s time we all did our bit to improve electrical safety in the home and that means educating the public...not misleading them. Richard Shaw Managing Director GreenBrook Electrical
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The ESC replies: The early stages of the Plug into Safety campaign needs to raise awareness of RCDs and the additional protection they provide. In our annual consumer survey, 60% of respondents stated that they didn’t know what an RCD was and 8% gave the wrong answer when asked to explain what it is (Source: MORI, April 2010). In order to get the RCD message to people when they are most receptive, the Council felt it important initially to target people when they are gardening or doing DIY or when an electrician is already working on their home/property. We therefore felt it most important to promote RCD adaptors and consumer unit replacement, particularly in the first year. By focusing on these two most accessible examples of RCD use we hope to ‘introduce’ the benefits of RCD protection in the simplest possible fashion. Experience has taught us that if we promote too complex, or too many messages, we are likely to confuse people. As we are planning to run this campaign over a five-year period, we will be referring to the various kind s of RCDs available in future activity. And in reference to the 50% figure quoted in the letter – 13 million homes do not have adequate RCD protection, rather that none at all. Angela Murphy Media Manager Electrical Safety Council
Letters We hope you like the new Letters column. Now all we need to do is to fill it regularly! I’m sure that there are many within the electrical industry that will have strong feelings about some of the issues raised in Switched On. So feel free to shout about them. Please email your letters to andrewbrister@ymail.com Please note that we will not be able to enter into correspondence regarding every letter received, nor will we have the space to publish every viewpoint. We reserve the right to edit letters for publication.
ANNUAL CONSUMER SURVEY 2010 psos Mori recently completed the Electrical Safety Council’s fifth annual consumer survey. It carried out over 2,000 face-to-face interviews and looked at public understanding of electrical safety issues in the home, as well as barriers and motivators for taking action.
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The survey asked whether people would be more likely to attempt electrical DIY in light of the recession and what factors would encourage people to choose a registered competent person. Word of mouth still key to selecting electricians Despite the internet giving people more ways to get information about tradespeople, word of mouth is still the most popular. Almost half (49%) of respondents said they would be most likely to use this method rather than online search engines (4%) or other directories’ websites (4%). The majority (70%) would not use any online tools when searching for an electrician. Strong support for electrical safety certification 78% of people believe that it should be a requirement for landlords to get the electrics in their properties checked on an annual basis. Over a quarter of people (28%) of people already believe that this measure is in place. Paying for an electrician in the recession The current economic situation appears to be having an impact on the way in which the British public are approaching DIY tasks around the home. A significant number of respondents indicated that, due to the recession, they would be prepared to carry out electrical DIY themselves, or ask friends or relatives to undertake work, rather than pay for a professional to do it. Almost a quarter (22%) said that they are now more likely attempt to wire in new sockets or install an oven without an electrician and, most alarmingly, one in ten said they would do likewise when rewiring a part, or all, of their house. SwitchedOn Issue 18 - Autumn 2010
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news ESC PUBLISHES TWO LEAFLETS ON DOWNLIGHTERS wo leaflets in the form of quick reference guides have been produced (in association with other leading bodies) to draw attention to the hazards associated with downlighters. The first is aimed at helping the trade to select and install them correctly, and the second targets householders to raise awareness of the importance of selecting the correct type and rating of replacement lamps.
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The guides have been produced in response to the conclusions from the Council’s investigations into claims that downlighters may have been the cause of a significant number of fires in homes. It is hoped that retailers and electrical wholesalers will demonstrate their support to this initiative by making the guides available at outlets where downlighters can be purchased.
The guides are available to view and download from the website at www.esc.org.uk
ESC CONTINUES BUSY EVENT SCHEDULE AT ELEX AND PARTY CONFERENCES
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ith a busy schedule of events behind us, the year will end with the Electrical Safety Council’s attendance at the Party Political Conferences in September and October and a packed two days at the Elex Show at Sandown Park on 30 November and 1 December.
Elex provides the ESC with the opportunity to hear first hand about the issues affecting electrical contractors working around the country and to show electricians the whole host of consumer literature and best practice guidance that the ESC has to offer.
Attendance at the Party Political Conferences has given the Council valuable opportunities to liaise with ministers and MPs as part of its public affairs programme of activity and will again provide access to key decision makers and influencers within government and opposition. The ESC’s public affairs work is focused on improving regulation, especially in the private rented sector, working with landlords to help them keep their tenants and properties safe.
The Electrical Safety Council is also proud to host an industry forum at Elex, bringing together panel members from Elecsa, NAPIT and NICEIC to discuss issues of importance to installers. The forum has been very well attended in the past and has produced some interesting debate on:
SwitchedOn Issue 18 - Autumn 2010
and Additions — applying the • Alterations regulations; Inspection Reports – proposed • Periodic change to Electrical Installation Condition Report, which will come in as part of Amendment 1 to BS 7671.
Tickets for Elex are available free of charge. Please register your interest at enquiries@esc.org.uk or visit www.elexshow.com
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news YOUR ESSENTIAL GUIDE TO THE WIRING REGULATIONS s announced in the Spring issue of Switched On, the ESC has made its definitive guide to complying with BS 7671 (IEE Wiring Regulations) and related standards available to all* - online.
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Fully updated to the ‘17th Edition’, The Essential Guide to the Wiring Regulations is a unique and authoritative source of reference on electrical installation safety matters. It’s the definitive guide to complying with the requirements of BS 7671, and related standards, for the electrical contracting industry and other qualified practitioners. The relevant requirements of BS 7671, other British Standards and Industry Codes of Practice are identified and amplified, and their implications explained. Many topics also incorporate data and other useful information on the subjects they cover. Formerly known as ‘the Technical Manual’, the constantly-developing Guide, which has already been many years in the making, currently comprises over 330 illustrated topics. In printed form, the topics would fill at least four large A4 binders. However, in this electronic age, all the topics are fully searchable on screen, and are hyperlinked to related topics. All the published topics are kept under review, and are updated as and when necessary. The Essential Guide is growing at the rate of about 40 new and significantly revised topics per year towards a target of 800 topics. But there’s no need to download updates – the latest version of the Guide is always the one online.
Forthcoming topics will cover aspects of the following subjects:
• Fused connection units • Replacement of accessories Regulations Approved • Building Documents (England and Wales) • Installation of electric central heating boilers trunking systems – current• Busbar carrying capacity and voltage drop sheathed cables to BS 8436 • Foil protective device requirements • Extra-low voltage lighting • Recessed downlighters – fire performance of small generators to supply mobile • Use or transportable units of 16 mm meter tails and • Adequacy 10 mm earthing conductors in existing 2
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domestic installations However, for those who might prefer to keep some of the essential information at their fingertips on paper, each of the topics is printable in full colour as a PDF. The online version contains a range of interactive features, including:
• Your popular searches • Your reading list • What’s new • Options for comments and feedback. • Dynamic search options and links 8
• Caravans and caravan parks • Construction sites In addition to the wide range of topics, subscribers to the online Essential Guide will gain access to additional technical material, including the latest BEAMA Guides. The intended users of the Essential Guide are persons trained to at least National Vocational Qualification (NVQ) Level 2 in electrical installation work, and having a good understanding of the requirements of BS 7671 and related standards.
The Essential Guide is a valuable source of technical information and guidance for all those involved in electrical installation and allied work, including:
• electrical engineers • electrical installation designers • electrical contractors and installers • building services engineers • building services maintenance engineers • colleges and training bodies • electrical equipment manufacturers • housing associations authority building control and • local environmental services departments • NHS Trusts • Facilities management companies A 12-month subscription to the online Essential Guide to the Wiring Regulations currently costs only £85 plus VAT, which is exceptionally good value. But the price is under review, so don’t delay. Subscribe at the ESC’s new Electrical Information Hub at www.eschub.org.uk
*By arrangement with the Council’s trading subsidiary NICEIC Group Ltd, the online version continues to be available free of charge to NICEIC Approved Contractors, NICEIC Domestic Installers and to NICEIC Partners.
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news ESC PARTNERS WITH TRADING STANDARDS he consumer watchdog Trading Standards has become the latest partner of the Electrical Safety Council, joining forces to help combat the issue of product safety.
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We reported in the last issue of Switched On that the Council is working hard to combat the increasing volume of counterfeit and dangerous electrical products available in the UK, some of which pose a high risk of serious injury or fire. In a bid to combat the growing market in unsafe goods, the collaboration between the Electrical Safety Council and Trading Standards hopes to use the knowledge and position that each has within their fields to ensure that information relating to unsafe electrical products can be shared via a secure online microsite which will enable information to be accessible to Trading Standards Officers out in the field. The aim of the mircosite is to: a database of recalls of electrical • provide products which can then be shared with
Over 2000 delegates attended the three-day event and visitors to the ESC’s stand included trading standards professionals, senior leaders and decision makers from local and national government - including the Office of Fair Trading, LACORS, and LBRO - as well as representatives from a range of business and consumer organisations. In addition to the information and advice being sought from the ESC team, future partnership and working opportunities were discussed for the coming year. The ESC had around 200 visitors to the stand and the strong presence was further cemented by the keynote welcome speech delivered by director general Phil Buckle. Also, the Council’s product safety manager Steve Curtler presented the popular mini theatre sessions on “Working with TSI for safer electrical products”. These attracted around 65 Trading Standard Officers. In addition to this activity, ESC materials were inserted in delegate briefcases and advertisements were carried in the conference promotional publications.
The event was a unique opportunity for the Council to network and promote current activities to large numbers of Trading Standards professionals, including the Trading Standards product recall interlink microsite and The Safe Shoppers Guide which has been produced to inform consumers about the most common problems with buying electrical products online. It also provided the team with the opportunity to raise awareness for the opening of this year’s Fire Safety Fund which welcomes applications from Trading Standards teams UK-wide to apply for funding up to £5k to support electrical fire prevention schemes at local level.
Next year’s conference will take place in Bournemouth at the Bournemouth International Centre between 21-23 June and will provide another opportunity for the Council to tell the sector about its work.
the wider public via individual websites a strong partnership and • build knowledge database in relation to electrical recalls that may be used in the future to clamp down on counterfeiting and unsafe products joint activity where resources • encourage can be shared for mutual benefit, eg. independent product testing and investigations, regional/national consumer awareness campaigns, funding for local consumer safety activities, regional projects, etc. The Electrical Safety Council is keen to extend partnerships within the industry and hopes that this new arrangement with Trading Standards will provide a wider benefit to the public as a whole. To further cement the close working relationship and to reinforce the two bodies’ shared passion for consumer safety, the Council was the main sponsor at TSI’s conference and exhibition which took place in Edinburgh in June. Trading Standards Institute’s annual conference is the leading consumer affairs and trading standards event in Europe and hosted 120 exhibition stands, interactive plenary sessions and mini theatre sessions.
SwitchedOn Issue 18 - Autumn 2010
Phil Buckle delivers the opening speech
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feature
Electric shock is not the only danger from electricity
Three separate incidents involving electrically-powered gates tragically illustrate the dangers of electrical equipment in use. o much of the general public, electric shock is the sole danger posed by electricity or electrically-operated equipment. However, many, especially children, don’t realise that electrical equipment can also pose a serious risk of physical injury when in use.
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Children are more vulnerable than adults when exposed to electrical or electrically-driven mechanical equipment; they don’t see the dangers or they may be inquisitive into the workings of the equipment. Electrically-driven gates are one example, as tragically illustrated by three separate cases involving children who have died from mechanical movement of this type of gate. The first accident involved a nine-year-old boy whose mother and sister watched as he was horrifically crushed by one of a pair of centrally-opening, wrought iron gates designed and installed for security reasons at some flats in Poole, Dorset. The gates were attached on either side to brick pillars by hinges, which resulted in a gap of 160 mm existing between the gates and the pillars. To prevent accidents, the Automatic Entrance Systems Installers Federation (AESIF) recommends gaps associated with electricpowered gates should be no more than 100 mm. A gap of 100 mm will generally protect against penetration of a head of a small child.
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At the flats there was also a gate activation switch fitted inside the development, intended for providing a simple means of opening the gates to exit the flats. However, this could be reached by a person approaching the gates externally, should they chose not to use the entry system provided on the outside. This effectively provided an unsafe means of activating the gates. On the day of the accident the boy approached the gates from outside the flats, squeezed part of his body through the 160 mm gap and reached out with his hand to operate the gate activation switch. Then as the gates opened inwards the 160 mm gap contracted, the boy became trapped and was crushed. He later died from his injuries. Three companies were later charged with contravening Section 31 of the Health and Safety at Work Act 1974; two companies were acquitted, however the company that manufactured and installed the gates was fined £80,000, with £40,000 costs. Following the accident the Health and Safety Executive (HSE) in February 2010 issued a Safety Notice* to remind organisations or individuals involved in the design, construction, installation, maintenance and/or commissioning of electrically-powered gates to the potential safety risks to pedestrians.
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feature
Figure 1: Guidance on gate safety
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Despite the HSE notice, two further fatal accidents involving the mechanical movement of electricallypowered gates have occurred, just five days apart. The tragic deaths of two girls aged five and six occurred in Bridgend, South Wales and Manchester, respectively. The two accidents, all though separate, had similarities:
• the gates were single electrically-powered; opening, the gates slide along behind a wall • when (see Figure 1); girls were pre-occupied playing games when • the the incident occurred; gates were activated and slid into the open • the position; • the girls were trapped and died from their injuries. The tragic accidents described above highlight the need to carry out risk assessments and comply with the measures found, for example, in the Machinery Directive 2006/42/EC and BS EN 12453: 2001 Industrial, commercial and garage doors and gates. Safety in use of power operated doors – Requirements. Competent installers, such as those approved by AESIF, are vital parts of the process where electrically-powered gates are required. To improve the safety measures of electricallypowered gate installations, there may be a need for additional protective measures to those generally
incorporated in such systems, for example an audible warning when the gates are operating and/or an emergency stop button. Indeed, Regulation 537.4.1.1 of BS 7671: 2008 Requirements for electrical installations requires a means to be provided for emergency switching of any part of an electrical installation where it may be necessary to control the supply to remove an unexpected danger. However, before a stop button is installed a risk assessment should be carried out to identify that an emergency switching arrangement does not introduce further danger or interfere with the complete operation necessary to remove danger (Regulation 537.4.1.4 refers).
three “cases involving children who have died from mechanical movement of electric gates...
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The UK is not alone in automation accidents. AESIF has reported that five fatalities involving automation occurred in Spain in 2009 and data obtained from the United States Consumer Product Safety Commission revealed that every year 800 children are treated in hospital for injuries from automated gates. In the light of this spate of tragic events, it is hoped that electrical contractors, installers and other interested parties will have a critical look at all electrically-operated gate installations they come across in the course of their work and, if possible, draw the attention of the owners to any evident dangers to children.
* HSE Bulletin No: FOD WSW 1-2010 (www.hse.gov.uk/safetybulletins/electricgates.htm) SwitchedOn Issue 18 - Autumn 2010
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feature HOMES MADE SAFE BY ESC GRANTS SCHEME
Grants are awarded to members of the community who are householders over 60 years of age
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who cannot afford to carry out the necessary electrical work in their home to make it safer.
During the last year, the Council enabled 486 grant beneficiaries across the UK to have urgent small-scale electrical works carried out by Care and Repair, the ESC’s partnering home improvement agency.
In the last year, Bristol Care and Repair assisted 110 clients with electrical work ranging from replacing failed light fittings and dangerous sockets and repairing electrical heating failures to upgrading earthing and bonding and replacing consumer units. The programme of works also included installing residual current device protection.
he Electrical Safety Council’s Grants Scheme continues to support vulnerable people in their local community, helping to provide them with a safer home environment.
In total, £79k was distributed between 11 local Care and Repair partners across the UK, which was used to safeguard the health, safety and wellbeing of vulnerable people in emergencies and in situations that would facilitate earlier discharge from hospital or avoid admission. Work completed under the scheme ranged from:
• urgent minor electrical works; installation condition reporting; • electrical and • portable appliance testing. Grants are awarded to members of the community who are householders over 60 years of age, on means-tested benefit and
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One of the many people the scheme was able to assist in Bristol was an elderly gentleman in his late 80s, who was in very poor health and in receipt of state pension with no savings. A fire in his kitchen had occurred as a result of water ingress around sockets close to the sink area, which caused three appliances to ‘short out’ and ignite. The gentleman was distressed as his wife was due to be discharged from hospital and no electrics worked in the kitchen because of the fire. Our funding allowed for the electrics to be repaired and enabled the gentleman’s wife to come home from hospital.
This case mirrored many others that the scheme has helped since its inception and highlights the positive effect it has had in helping vulnerable people to make their homes safer. Lindsay Hay, the service manager at Bristol Care & Repair said: “The scheme has been extremely useful for our frontline advisors who have been able to arrange emergency works for clients having very little income or savings, and without delays caused by having to complete detailed funding applications.” Bristol Care & Repair also said that the scheme has resulted in them giving a greater focus to electrical safety issues in their own training programmes that are delivered to health and social care workers in the area. This year, £80k of grant funding has been allocated and the Council will continue to work in partnership, at local level, with home improvement agencies.. Further details and information is available on the website at www.esc.org.uk.
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Have you ever been asked...
Is it permitted to earth the electrical installation of a caravan to a PME earthing facility when kept at home
?
Many owners of a touring caravan or motor caravan choose to store their caravan at home, such as on a driveway, when not in use for holidays. Some owners also connect their caravan’s 230 V electrical installation to the electricity supply of their home to keep the caravan’s battery charged and to allow the mains-voltage socket-outlets and lights in the caravan to be used. However, in a high proportion of homes in the UK, a Protective Multiple Earthing (PME) facility is used as the means of earthing for the installation (TN-C-S system).
Therefore, where a PME facility is used as the means of earthing for the installation of the home, it is recommended that a socket-outlet be provided external to the building. The socket-outlet should be supplied through an RCD meeting the requirements of regulation 415.1.1 for additional protection, and connected to an installation earth electrode meeting the requirements for a TT system. Figure 3 shows a typical arrangement for doing this. Figure 3: Typical supply and earthing arrangement for an external socket-outlet to supply a caravan at home
This leads to the question of whether it is permitted to earth the installation of a caravan to the PME facility when stored at home, given that regulation 9(4) of The Electricity Safety, Quality and Continuity Regulations 2002 (ESQCR), requires that: ‘The distributor shall not connect his combined neutral and protective conductor to any metalwork in a caravan or boat.’ The question does not apply where the installation of the home is earthed to a means other than a PME facility – that is, to a separate protective conductor of the supply, where provided (TN-S system), or to an installation earth electrode (TT system). The reason for the requirement of regulation 9(4) is given in the Publication URN 02/1544 – Guidance on The Electricity Safety, Quality and Continuity Regulations 2002, issued by Engineering Inspectorate of the former Department of Trade and Industry. ‘The particular risk at these installations arises from the possibility of the supply neutral conductor becoming disconnected from earth, possibly causing the metalwork in the caravan or boat to rise to live potential (assuming that the caravan or boat does not benefit from an independent connection with earth). Persons entering or exiting the caravan or boat would then be at risk of electric shock.’ Connection of a caravan to the supply at home Caravanners wishing to connect their caravan to the electrical supply of their home usually do so by using the caravan’s 25 m ‘hook-up’ lead (see Figure 1) and connecting this to a socket-outlet of the home’s installation. This connection to the socket-outlet generally requires the use of a 13 A to 16 A adaptor, such as that shown in Figure 2, as a hook-up lead is fitted with a 16 A BS EN 60309-2 plug as standard, to suit the pitch socket outlets at caravan parks.
Figure 1: Caravan hook-up lead
Figure 2: Typical 13 A 16 A adaptor
Earthing for the caravan Whatever means is used to connect the caravan to the supply, a PME earthing facility should not be used as the means of earthing for the caravan. To do so would involve connecting the combined neutral and protective (PEN) conductor of the supply to metalwork in the caravan, which is not permitted by ESQCR regulation 9(4), mentioned earlier. SwitchedOn Issue 18 - Autumn 2010
1) The socket-outlet should have a degree of protection (IP rating) suitable for its external location. 2) The RCD should have a rated residual operating current (I∆n) not exceeding 30 mA and an operating time not exceeding 40 ms at 5 I∆n, as required by Regulation 411.3.3. 3) The earth electrode should be selected and installed in accordance with Regulation Group 542.2 and have no electrical connection with the PME earthing terminal. The resistance of the earth electrode should be as low as practicable and not exceed 1667 Ω. A value exceeding 200 Ω may not be stable. BS 7671 Table 41.5 refers. 4) The socket-outlet should not be installed inside the building, as this may result in equipment in the home being plugged into the socket outlet, which could in turn result in exposed-conductive-parts that are connected to different earthing systems being simultaneously accessible, contrary to the requirement of Regulation 411.3.1.1.
The arrangement in Figure 3 reflects the requirement of Regulation 708.553.1.14 for the earthing of a caravan pitch socket-outlet at a caravan park. The regulation requires that the socket-outlet shall not be connected to any PEN conductor of the electricity supply, but shall be connected to an earth electrode, and that the requirements of Regulation 411.5 for a TT system shall be met. Essentially the same requirement is found in Engineering Recommendation G12/3 – Requirements for the application of PME to low voltage networks, issued by the Energy Networks Association. Clause 6.2.6 states that ‘Supplies to caravans and boats should be two wire phase [line] and neutral supplied through an RCD which must be supplied by the site owner. An independent earth electrode is required …’
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technical Spotlight on…BASEC and cable safety
In light of the recent warning to the UK electrical industry to be vigilant for recent batches of 'Atlas Kablo' branded cable, Jeremy Hodge of BASEC discusses the importance of taking all necessary precautions to check your cables are safe The British Approvals Service for Cables (BASEC) has advised the electrical sector to be vigilant for recent batches of Atlas Kablo branded cable that has been found to have insufficient copper, leading to excessive conductor resistance. As soon as the problem was brought to BASEC's attention by a vigilant distributor, Atlas Kablo had its BASEC licence suspended due to the scale and severity of the problem (the licence has subsequently been cancelled, see box). The manufacturer was required by BASEC to investigate, to communicate with customers and to assist the market in locating and recovering affected product for scrapping. A communication was sent to distributors, buying groups, wholesalers and contractors to ensure they checked and quarantined affected cable. Cable from manufacturers holding a BASEC licence is regularly retested with a range of assessments to ensure conformity. Unfortunately, suspect cable products can often be found in the UK marketplace and historically these have not been subject to the same level of scrutiny or action. Now, however, organisations such as BASEC and the Approved Cables Initiative are active in responding to leads from installers and traders, testing cable, identifying sources, and providing warnings to the market. All public warnings and further advice can be found on the BASEC and Approved Cables Initiative websites www.basec.org.uk and www.aci.org.uk. Electrical contractors, specifiers and electricians who purchase and install cable have a responsibility to ensure that the cable they specify meets British and/or European standards to ensure compliance with the Wiring Regulations. In some cases markings on the cable sheath can be misleading, or even make false claims of compliance with a particular standard. Always look for a manufacturer's mark that you recognise. For peace of mind, you should also insist on an independent third-party approved cable with either a BASEC, HAR or equivalent mark. It is also important to specify on your order the British Standard (BS) number the cable must comply with. Installers who are concerned that affected cable may have been used should ensure they check that the necessary electrical installation
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verification tests have been performed by a qualified and competent electrician. Any performance concerns following these tests should be investigated to ensure circuits are safe or need protection enhancement or cables replaced. We would advise that you keep records of all purchases, including reel ends with batch markings, receipts from distributors and sales records on your computer system. If you are unsure of the cable and have any scrap lengths, these can be sent to the BASEC for checking and testing. Jeremy Hodge is chief executive of the British Approvals Service for Cables (BASEC). Further information and guidance may be obtained from BASEC at technical@basec.org.uk Tel: 01908 267300, or at www.basec.org.uk
Atlas Kablo licence cancelled On Monday 17 May 2010, BASEC suspended the product certification licence of Atlas Kablo, of Denezli, Turkey. The licence is now cancelled and the company no longer holds a BASEC product certification licence. As a consequence, the use of the BASEC registered trademarks in connection with cable produced by Atlas Kablo is no longer authorised and cable produced by Atlas Kablo bearing the BASEC registered trademarks should not be sold. The reason for the suspension was a serious decline in quality across the company’s range of products. Affected cable has excessive conductor resistance (insufficient copper). BASEC advises that affected cable should not be sold or installed, and to seek advice if it has been installed.Atlas Kablo has notified its customers, issued a letter of guidance and posted a list of affected batches of cable on the Atlas Kablo website (www.atlaskablo.com). The quantity of cable involved is 11 million metres, and identified batches are production with a “2010” manufacturing date. Cable traders, wholesalers and contractors should check what cable they have in stock, quarantine affected cable and notify their supplier about recovery, or contact Atlas Kablo direct.
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technical Progress of investigation into in-service reliability of RCDs We report on phase three of the Council’s study into RCD performance Phase three of the Council’s research into the reliability of residual current devices (RCDs) in domestic premises got underway last year. The research, commissioned by the Council, was carried out by ERA Technology with the principal aim of investigating abnormal factors that could potentially affect the operation of RCDs, compare the performance of voltage-dependent and voltage-independent RCDs and investigate alternative technologies for auto-testing of RCDs. After consultation with the Council’s RCD Research Steering Committee, comprising representatives from ECA, BEAMA, Schneider Electric and Greenbrook, the test programme was set as follows:
and 1000 A for comparative purposes. The results of the testing showed that degradation of the RCD main contacts can occur at both 500 A and at 1000 A, as shown in Figures 1 and 2. The damage shown in both Figures 1 and 2 is commensurate with expected results and is within acceptable limits, according to the RCD Research Steering Committee.
Circuit conditions that could affect RCD operation The research involved carrying out a desktop exercise to investigate what installation conditions could in theory lead to malfunction of the RCD. These theories were then replicated and simulated in laboratory tests. The main conclusions of the findings are as follows:
the adequacy of RCD main contacts under fault current • determine Neutral-to-earth faults conditions An RCD will detect and operate in the presence of a neutral-to-earth the circuit conditions that could affect the operation of • explore fault in the following circumstances: RCDs, including the effects from fault conditions there is a neutral-to-earth voltage, caused by the voltage • where the influence of connected loads, in particular the • determine drop along the neutral conductor, or influence of capacitive loads there is a load connected, part of the load current then • where whether equivalent technologies exist that can be relied • investigate flows back to the source of supply via the earth return thus upon without the need for periodic testing by users. operating the RCD.
The project, which is now nearing completion, has involved a combination of desktop research and, where appropriate, laboratory testing using simulated installation conditions. Although the final report has been drafted, there are still some points that require further discussion and deliberation with the RCD Steering Committee and RCD test instrument manufacturers. Once these points have been finalised, the ESC hopes to include a more detailed summary of the results from the research in the next issue of Switched On. In the meantime, some of the main findings from the research to date are as follows:
However, in an installation forming part of a TT system, a high impedance earth combined with a neutral-to-earth fault can cause RCDs (RCCBs and RCBOs) not to operate. This is because if a line-toearth fault occurs in an installation having a pre-existing neutral-toearth fault the fault current will split between the neutral and earth. If the earth path is of sufficiently high impedance the portion of current flowing down it may not be enough to cause an imbalance and to cause the RCD to operate. Open-circuit PEN conductors
RCD main contacts The RCD product standards BS EN 61008-1 and BS EN 61009-1 require a test current of 500 A or 10 I∆n (whichever the greater) for checking adequacy of RCD main contacts for breaking fault currents. However, previous research shows that prospective earth fault currents upwards of 1000 A are not uncommon in domestic installations. To simulate the adequacy of RCD contacts breaking earth fault currents in line with those found in typical domestic installations, it was decided that the laboratory testing should apply a test current of both 500 A
In an installation forming part of a TN-C-S system with an open-circuit PEN conductor, the circumstances of whether the RCD will operate depend on its type. With voltage-independent RCDs, an open-circuit PEN conductor should not affect the operation of the RCD under lineto-earth fault conditions, as long as there is a sufficiently low impedance path back to the source of supply. However, under the same conditions, but with a voltage-dependent RCD, the resulting line-toearth voltage during the earth fault may not be sufficient for the amplification circuit to operate the RCD.
Influence of connected loads The research indicated that for circuits containing capacitance, such as for motor starting, filters for IT equipment or EMC requirements, RCD trip times shown on the oscilloscope can be shorter or longer than the time recorded on the RCD test instrument. This disparity between measurements was more significant depending on what make and model of RCD test instrument was used.
Figure 1: Fixed contact and conductor after 500 A test
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Figure 2: Moving and fixed contacts after 1000 A test
To this end, the Council is in the process of discussing these results with manufacturers of RCD test instruments. Once the discussions are complete, a report of the research findings will be published on the ESC’s website www.esc.org.uk and a more comprehensive article will be developed for Switched On.
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technical Assessing the general characterisics of a domestic electrical installation For either a new installation, or an alteration or addition to an existing installation, Part 3 of BS 7671 requires an assessment to be made of the general characteristics, including the maximum demand. These characteristics are to be taken into account in the choice of protective measures (Part 4) and in the selection and erection of equipment for the installation (Part 5). With the exception of the maximum demand, this article gives guidance on assessing the general characteristics for the electrical installation of an individual dwelling (house, bungalow or flat). Guidance on assessing the maximum demand for a dwelling will be given in a future issue of Switched On. General
purpose of the installation, its general structure and its • The supplies (Chapter 31) • The external influences to which it is to be exposed (Chapter 32) • The compatibility of the electrical equipment (Chapter 33) • Its maintainability (Chapter 34) • Recognised safety services (Chapter 35) • Assessment for continuity of service (Chapter 36) Purpose, structure and supplies (Chapter 31) Chapter 31 identifies particular characteristics relating to the purpose, structure and supplies of the installation that must be determined and taken into account. An abbreviated checklist of these characteristics is given in Table 1. Table 1: Checklist of characteristics relating to purpose, structure and supplies a) The maximum demand (to be covered in a future issue of Switched On) b) The number and type of live conductors (generally one line and a neutral) c) The type of earthing arrangement (generally TN-S, TN-C-S or TT) d) The nature of the supply or supplies, including: (i)
nominal voltage(s) and characteristics, including harmonic distortion
(ii)
nature of current (ac or dc) and frequency
(iii) prospective short-circuit current at the origin of the installation (iv) earth fault loop impedance at the origin (Ze) suitability of the installation for its required purposes, including maximum demand
(vi) type and rating of the overcurrent protective device at the origin (supply main fuse) Note: The characteristics in (a), (b), (c) and (d) must be ascertained for an external supply and determined for a private source, such as a generator. This applies equally to main supplies, standby supplies and supplies for safety services.
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• the number of phases (generally one for a single dwelling) • the frequency (generally 50 Hz) • the nominal voltage (generally 230 V line-to-earth) maximum prospective short-circuit current at the supply • the terminals earth fault loop impedance of that part of the system • the external to the installation ( ) type and rating of the distributor's protective device or • the devices nearest to the supply terminals type of earthing arrangement applicable to the connection • the (TN-S, TN-C-S or TT). Ze
Regulation 300.1 requires the following characteristics of an installation be assessed, in accordance with the Chapters indicated.
(v)
Information about items b), c) and d) of Table 1 for the main incoming supply to an installation can be obtained from the electricity distributor. Some distributors make this information available by publishing notes of guidance giving:
External influences (Chapter 32) Part 2 (definitions) of BS 7671 defines an external influence as: “Any influence external to an electrical installation which affects the design and safe operation of that installation.” The electrical installation designer must assess the external influences to which each part of the installation is likely to be exposed during installation, use and maintenance. The external influences must be taken into account in the choice of measures of protection for safety and selection and erection of equipment for the installation. (Regulation Group 512.2 and Section 522 refer.) Examples of external influences include ambient temperature, presence of water and high humidity, impact and solar radiation. Appendix 5 of BS 7671 gives a comprehensive list of external influences, some of which will apply to the installation in a dwelling. A bathroom or shower room is a location in a dwelling where the presence of water and high humidity needs particular consideration. In Section 701 of BS 7671 – Locations containing a bath or shower – Regulation 701.512.2 specifies the minimum degrees of protection (IP ratings) for electrical equipment, including wiring systems, to be installed in each of zones 0, 1 and 2 of the location. Compatibility of the electrical equipment (Chapter 33) Regulation 331.1 requires an assessment to be made of any characteristics of the equipment of an installation likely to have harmful effects on other equipment or services, or be harmfully affected by them, or impair the supply. Examples of such characteristics (listed in Regulation 331.1) include transient overvoltages, undervoltages and excessive protective conductor currents. For an installation in a dwelling, the main practical consideration regarding compatibility is to follow manufacturers’ instructions in applying and installing equipment. For example, where lighting is to be controlled by a dimmer, the luminaires must be suitable for this purpose. Certain types of luminaire, such as fluorescent and extra-low voltage, require special controlgear to SwitchedOn Issue 18 - Autumn 2010
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technical achieve dimming. Also, the dimmer must be adequately rated for the load current and for the type of load (resistive or inductive). Maintainability (Chapter 34) Regulation 341.1 requires an assessment to be made of the frequency and quality of maintenance that an installation can reasonably be expected to receive during its intended life. The reason for the assessment is to allow the equipment and protective measures for the installation to be chosen and installed so that, for the intended life of the installation: periodic inspection, testing, maintenance and repair likely to • the be needed can be readily and safely carried out; protective measures must not diminish for safety to remain • the effective; • the reliability of equipment for proper functioning is sustained. Wherever practicable, the wiring and other equipment of the electrical installation in a dwelling should be of a type requiring little or no maintenance. Where maintenance is necessary, the equipment concerned should be selected and installed to make it as simple and safe as possible to maintain, especially where it may be worked on by the householder. For example, luminaires should not be positioned where it would be difficult to gain access for re-lamping. Safety services (Chapter 35) The only safety services likely to be required in a dwelling are a fire alarm and fire detection system (generally smoke alarms and possibly
some heat alarms) and, exceptionally, an emergency lighting system. Any requirement to provide either of these in a dwelling will be found in guidance that supports national building regulations. This guidance is given in Approved Documents in England and Wales, the Technical Standards that support the relevant building regulations in Scotland, and in Technical Booklets in Northern Ireland. Continuity of service (Chapter 36) Continuity of service is not usually a major issue for the electrical installation of a dwelling but it needs to be considered nevertheless. The one and only example that Chapter 36 gives where continuity of service may be considered necessary during the lifecycle of an installation is for a life support system, which is not found in most dwellings. Where continuity of service is an issue for any circuit of the installation, the characteristics listed in Regulation 361.1 should be considered. These include (amongst others) the number of circuits, the use of monitoring equipment, and multiple power supplies.
Private tenants at increased risk of electric shock New research for the Electrical Safety Council has highlighted the risks people are exposed to from electricity1. It demonstrates the high level of risk to tenants in private properties, and where the threat of injury lies. This new research gives a clear picture of the danger to the UK population from both electrical installations and products. Worryingly, while only 14% of the population live in privately rented accommodation2, some 20% of people who experienced electric shocks live in privately rented homes. This suggests that private tenants are at disproportionately high risk of electric shock. Previous studies conducted on behalf of the Electrical Safety Council have indicated that privately rented properties are among the least likely to have RCD protection in the consumer unit, with 52% left unprotected3. The survey asked people what had caused their injuries. The two biggest causes were using faulty appliances (21%) and carrying out repairs or maintenance without having turned off the electricity at the mains (20%). This highlights both the need to ensure that electrical products are maintained in good working order, and the importance of having repairs carried out by someone who knows how to work safely on electrical products and fixed wiring.
Electrical installations and lighting remain a major contributor to electric shocks. Between them they accounted for two fifths (43%) of all electric shock injuries. Nearly a quarter (23%) of people who had had an electric shock in the last five years reported being burnt as a result. Over one in six of the 23% were left scarred by the burn ie 4% of the total sample. This work will continue to inform the ESC’s campaigning activity. As the Council gets more clarity on which groups are most at risk from injury from contact with an electric current, it can focus its campaigning work and help those people most at risk to protect themselves from danger. 1 All data unless otherwise indicated from Ipsos Mori: 1024 adults aged 18-65 in Great Britain who have personally experienced an electric shock that resulted in injury while at home or in the garden in the past five years, interviewed via Ipsos online panel 25 June - 2 July 2010 2 http://www.communities.gov.uk/documents/statistics/ pdf/1346249.pdf, pp11 (England data) 3 Data supplied by BRE (formerly the Building Research Establishment), used to inform the English Housing Survey
The study also revealed that 64% of those injured by electric shock across all age groups were men. However, this varies greatly with age: of those aged 55+ who reported having an electrical shock, 73% of those injured were men, whereas in the 18-24 age range, equal amounts of men and women reported being injured. SwitchedOn Issue 18 - Autumn 2010
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Investigation into overloading of four-way extension leads We investigate the issues of overloading four-way extension leads fitted with a 13 A BS 1363 fuse As part of the Council’s electrical product safety screening programme, and following several reports of fires where the source of ignition was attributed to a four-way extension lead, the ESC decided to investigate and replicate the effects of overloading of these products. Also, the Council’s latest research into electrical product risk categorisation indicated that extension leads are a high priority for further investigation and for evaluation regarding safety and compliance with product standards.
Use and misuse Extension leads are used in most households as a temporary means for supplying equipment for purposes such as DIY and gardening. They are also used as a more permanent means for supplying several electrical appliances in households, usually because the number of fixed socket-outlets is insufficient. In most cases, extension leads are used either for short periods, as would be the case for DIY or gardening work, or for longer periods to supply appliances operating at relatively low currents. In some instances, however, several high current-using appliances, such as electric heaters, are plugged into an extension leads or several extension leads are coupled together with numerous electrical items plugged into the available outlets. The consequences of such actions can be that the total current flowing through one or more extension leads exceeds the maximum rating of 13 A (or 5 A for lower rated extension sets). The overloading of extension leads is arguably a foreseeable condition despite the presence of permanent marking on the product, warning against exceeding the maximum rated current. It is also reasonable to suggest that most members of the general public would, if asked, think that the 13 A fuse fitted in the supply plug will provide overload protection in the event of them unwittingly exceeding the maximum current rating. However, this is simply not the case.
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Product testing The national standard for extension leads, BS 1363-2: 1995, specifies a maximum ‘continuous use’ rating of 13 A for the fitted plug and socket-outlet. The test current is set marginally above this at 14 A for type-testing, to determine compliance with the product standard. Standard BS 1362: 1973, covering the fuse link, requires the fuse to operate at 1.9 times rated current (that is 24.7 A) within 30 minutes, and also that the fuse shall have a non-fusing current of 1.6 times rated current (that is 20.8 A). It is therefore possible for an extension lead to carry a total current of 20 A for an indefinite period. While this may not be a common situation, the product testing undertaken was to determine whether it is possible to overload extension leads such that they might pose a fire hazard.
After consideration of various other factors that could affect safety, the test programme was set as follows:
• Visual assessment of fitted plug (under BS 1363-1) • Visual inspection of fuse including counterfeit indications • Measurement of supply cord conductor cross-sectional area • 5000 insertions/withdrawals, on one socket from each type endurance test assessments, including shutter • Post operation, access to live parts, insulation resistance and electric strength rise test at 20 A, the total load being divided • Temperature equally between two of the possible four socket-outlets. Minimum test duration being time to operation of the fuse with maximum duration of four hours. Seven samples were tested: six were randomly selected and purchased and one sample was tested that had been in use at the Council’s office.
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technical Product testing results All of the fitted plugs satisfied the visual assessment under BS 1363-1. The fuse in each fitted plug appeared genuine and contained the expected quantity of sand filler (used for assisting arc extinction). The cross-sectional area of flexible cord conductors for each sample was marked as 3 x 1.25 mm2, which was verified by measurement and was correct in each case. Each sample passed the 5000 insertion endurance test with no evidence of damage and the socket-outlet shutters continued to shield live parts. All except one of the samples passed the insulation resistance testing. The exception was the sample that incorporated RCD protection where damage after the overload test prevented the application of the 6 kV insulation resistance test. As expected, it was the results of the overload and temperature rise test that gave the most concern. In all but one case, the supply lead plug on each sample showed varying states of overheating damage and enclosure deformation. The accessible surface of the fitted plug
was measured for five of the seven samples. The lowest recorded temperature was 84.5oC and the highest was 200oC. This highest temperature softened the plug body leaving the line conductor pin in the mains socket-outlet after the test, as depicted in Figure 1. Significant damage was also observed for one other sample where the accessible surface of the plug reached 153.4oC, as depicted in Figure 2.
Conclusions and next steps It is possible and arguably foreseeable to overload extension leads, resulting in hazardous conditions, and that the fitted supply plug appears to be the weakest component part. The limited insertion endurance test of 5000 operations was an attempt to simulate poor contact within the four-way extension but this did not highlight any such concerns for the limited sample size of seven products. The accessible surface temperature of two samples reached 153oC and 200oC, which was sufficiently high to cause damage to the supply plug body, leading to an electric shock hazard. This was especially apparent during the testing of the sample where the line conductor pin became detached from the plug and remained in the socket-outlet. For the samples where damage to the plug was observed, an obvious odour was present after about 20 minutes into the overloading. This would be likely to provide sufficient time for the user to take action, if someone was in the house and was awake at the time.
Figure 1: Line conductor pin stuck in socket-outlet
The maximum temperatures of 153oC and 200oC are also slightly below the ignition temperature of most furnishings and paper that might be in close proximity to the fitted plug. This leads to the question whether the reported fire incidents are more likely to have resulted from poor contacts within the socket-outlets of the four-way extension block, rather than from overloading. While this is feasible, it is difficult to fully support this supposition with such a small sample size. To this end, the Council will continue to liaise with Trading Standards Officers and Fire and Rescue Services with the aim of collating more detailed evidence from incidents involving four-way extension leads. Misuse of electrical products is outside the scope of the Electrical Equipment (Safety) Regulations, so further discussion needs to take place to determine whether foreseeable conditions of overloading of extension leads constitutes a required change in the regulations and product standards. The Council will raise this issue through its representation on various product standard committees.
Figure 2: Damage to supply plug exposing line conductor pin
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Nevertheless, the findings of the research reinforces the need to provide consumer advice about the dangers of overloading extension leads with further suggestions for keeping the area around the extension set free from dust and other combustible materials. We will also encourage users of extension leads to carry out regular visual checks to look for signs of overheating damage at the plug and socket-outlets and to do routine maintenance operations on the supply plug, flexible lead and four-gang socket-outlets. A copy of the test report is available in the ‘business and community’ section of the Council’s website www.esc.org.uk
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Exploring the EU Injury Database (IDB) for consumer product risk categorisation Research carried out by the Council shows how the EU Injury Database played a vital part for categorising the risks associated with electrical consumer products.
Figure 1: Breakdown of electrically-related injuries per product category
Although the UK has a fair record of electrical safety, someone dies every week in an electrical accident at home. Further, there are an estimated 4,000 injuries and 8,000 fires in people’s homes caused by an electrical fault every year and nearly 113,000 estimated injuries are caused by using electrical products without due care. To help the Council achieve the greatest impact and benefit for consumers, it carried out a risk categorisation exercise for electrical consumer products. This involved analysing data from sources, such as EU RAPEX, UK fire statistics, Trading Standards, newspaper clippings and from consumer incidents reported on the Council’s website (www.esc.org.uk ). However, to produce risk categories that considered all contributing factors, the ESC needed to include a factor for injuries caused by using electrical products.
Injury data The UK system for collecting injury data was, until 2002, the Home and Leisure Accident Surveillance Systems. But, unfortunately, in 2002 the Government ceased to collect this data for the UK. Since then the range of electrical consumer products available in the UK has increased year on year. The vast majority are now manufactured in the Far East and imported, and there has been a rapid growth in the purchase of electrical products over the internet. Hence the HLASS database is now of limited value in assessing injury rates and trends. To this end, the Council turned to the EU Injury Database. Injury data was analysed from a sample of 84 hospitals from eight European Countries between the years 2005 and 2007. This represented a good cross-section of EU countries and cultures from which detailed analysis was carried out and estimates were made by extrapolating into 27 EU member countries. Analysis of the 2005-2007 injury data indicated an estimated 1,212,000 injuries being attributed to electrical products or 2.96% of the total cases. The vast majority of these cases are due to physical injury and are not directly attributed to the electrical integrity of the products concerned. The breakdown of the results for electrical products is shown in Figure 1.
Other contributing factors Evaluation of electrical consumer products notified as being unsafe under RAPEX, indicates that in most cases the product standards
BACK ISSUES OF SWITCHED ON
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written to support the Low Voltage Directive are either not understood or not properly followed. However, the fact that products do not pose an electric shock risk does not mean that they do not pose a safety risk. For example, health and beauty products that may be used close to the body that are either sharp or emit heat may pose a risk to consumers or vulnerable users. Another key factor is unnecessary child appeal built into the design of products that could be a hazard to children eg kitchen and cooking appliances shaped to look like an animal. Such products should be supported by an appropriate risk assessment and risk management process. In terms of domestic fires in the UK, the general trend is that the number of electrically-related fires is decreasing. However, the number of fires due to electrical consumer products accounted for over 90% of all fires having an electrical origin in the 2007 UK fire statistics.
Conclusions Taking all relevant data sources into account, the following is a list of products registered as high priority for further research and evaluation regarding safety and compliance. These products will also be considered in the future safety screening programme conducted by the Council: • Lighting chains • Night lights • Hair straighteners /curling devices • Deep fat fryers • AC/DC adapters for toys • Extension leads • Kitchen and cooking devices with play value • Residual current devices (RCDs) Additionally, the Council continues to lobby the government to develop and implement an appropriate database to collect injury data, as required by the EU.
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