www.esc.org.uk
Issue19 | Winter 2010 | ÂŁ5.00
Green goo clean up
dealing with a legacy from the 1960s
WELCOME Articles support the ongoing modernisation of the Charity and will, with the continued support of our Trustees, staff and stakeholders ensure we continue to fulfil our objectives and meet the all-important public benefit test set by the Charity Commission.
’m writing this having just heard the headlines from the Chancellor’s spending review and while I don’t have a crystal ball, I am pretty certain that we all face some challenging times in the coming years as the austerity measures take effect.
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The Electrical Safety Council is very aware of the difficult global economic situation and the likely impact on the Charity and its beneficiaries. To this end the Charity is ensuring that it is well positioned to meet the challenges of the future. On 30 September a new set of Articles was approved at the Council’s AGM. The changes to the
The Charity has just completed work on a new five-year strategy and the goals set by Trustees are now being incorporated into a new three-year rolling business plan. It is imperative that we deliver on the objectives in the plan. Both myself and my team will be measured against these objectives as part of the ongoing review of performance by Trustees to ensure that we are delivering to our beneficiaries and that we are being financially prudent in everything we do. It is also important that we marshal our finances in a responsible way as funding of the Charity is predominantly from electrical contractors
registered with the NICEIC, and it is likely that the electrical installation industry will be significantly affected during the current round of spending cuts so prudence is required. You may well be aware that since the coalition government took office there has been much said about cutting red tape and of course the Building Regulations, and particularly Part P, have been the focus of people’s ire. Yes, I do agree that Part P has not been seen as the electrician’s friend but it has benefited the consumer. As it does contribute to safety, the Council will continue to lobby Westminster for its retention and we made our support for Part P clear at the party conferences held in the autumn of 2010. We have already sent comments to the Minister, Andrew Stunell, as part of an initial review of the Building Regulations and we have also participated in a workshop on the future of the Building Regulations.
Our whole raison d’être is to ensure the safety of all users of electricity and it would not be acceptable to the ESC if we were to allow a vacuum to appear whereby anyone could undertake electrical work without any checks - which would surely be the case should Part P be scrapped. I agree it’s not perfect but we do have ideas to make it more cost effective and easier to enforce. We will be discussing these views with industry colleagues at an event we will be hosting in January on the future of Part P, so if you have a view please pass it on to your scheme operator. On a final note, I hope that you have a peaceful Christmas and may I offer you and your families a successful New Year. As always, we would welcome feedback on Switched On, to help us improve the content. Email feedback@esc.org.uk Phil Buckle Director General
Have you tried the ESC’s Essential Guide to the Wiring Regulations, the ‘must have’ online information tool for electrical installation designers, specifiers, installers and verifiers? Well respected in the industry, this authoritative, fully-searchable online resource currently contains over 300 articles (known as ‘topics’) covering a wide range of relevant subjects to help you in your work or studies. Subjects are clearly explained with the aid of full colour illustrations, diagrams and tables. The Guide is expanded and maintained by the addition of 40 new or updated topics throughout each year, all included in your subscription.
Go to www.eschub.org.uk for a FREE 7-DAY TRIAL or to subscribe.
ESC publishes 2009/10 annual report - see page 9
issue 19 Winter 2010
switchedon your insight into the electrical safety industry
news
technical
features
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Welcome
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Spotlight on... the JIB
10 Green goo continues to be a
News in brief
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Have you ever been asked...
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After the flood has gone Also, Websites now include sign language
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ESC investigates consumer concerns over compact fluorescent lamps
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Assessing the maximum demand of a domestic electrical installation
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Letters
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Plug into Safety campaign continues apace
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Successful partners announced for this year’s Fire Safety Fund awards Also, ESC helps to create safer migrant communities
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ESC publishes 2009/10 annual report
SwitchedOn Issue 19 Winter 2010
nuisance to householders and to electrical installer
20 ESC reaches out safety messages to Switched On Kids
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 Tackling rogue landlords Housing and homelessness charity Shelter has recently launched a campaign tackling rogue landlords in a bid to raise awareness of rent scams. According to Shelter, almost one million Britons have fallen victim to scams involving a private tenancy or landlord in the last three years. The charity has also revealed that over 90% of environmental health officers said they had encountered cases of severe damp, mould, electrical or fire safety hazards in properties they investigated in the last year. Campbell Robb, chief executive of Shelter, said: “With more and more people set to become private tenants in the future we believe this is a widespread problem that will create thousands more victims unless we urgently do something about it.”
Until about March, all our Best Practice Guides can continue to be viewed on, or downloaded free of charge from, the ‘Business and Community’ section of our main website www.esc.org.uk. After that, all the information intended for the electrical industry will be found in a new dedicated section of a fully redesigned website.
Firm fined after boiler suit fire An Aberdeen building firm has been prosecuted after a joiner's boilersuit was set on fire when a short circuit caused a localised electrical explosion. George Forbes, 62, was working for Graeme W Cheyne (Builders) refurbishing flats when he attempted to move a fuse cut-out because he needed to fit new plasterboard behind it. Unknown to Mr Forbes, the fuse cut-out was still live and connected to a 415 volt cable when he touched it. The HSE investigation revealed that the cable was twisted, causing a shortcircuit that created enough energy to melt the cable and create a small explosion. Graeme W Cheyne (Builders) pleaded guilty to breaching Section 2(1) of the Health and Safety at Work Etc Act 1974. The firm was fined £9,000 and ordered to pay Mr Forbes £4,000.
Best Practice Guides 7 & 8 As advised in the autumn issue of Switched On, two new Best Practice Guides have now been published: Best Practice Guide No 7 - Test instruments for electrical installations: Accuracy and consistency
Atlas Kablo – an update BASEC and the Approved Cables Initiative (ACI) have revealed that cable manufactured by the Turkish company Atlas Kablo as early as 2009 has now been identified as faulty following recent cable sample testing.
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“We believe that cables manufactured by Atlas Kablo should now be treated as suspect and urge contractors and installers to consider and review where they have already installed these cables and to seek guidance from qualified electrical authorities as to what action needs to be taken,” says the ACI. Atlas Kablo, which now appears to have ceased production, had its BASEC product certification licence cancelled and is no longer authorised to use the BASEC registered trademarks. Atlas Kablo’s HAR licence has also been removed. www.aci.org.uk
Luton companies ignored warnings on electrical equipment Three Luton car repair companies have been fined a total of £4,000 for failing to act on electrical defects in their workshops - exposing their workers to a serious risk of injury. On 6 September 2010, the Health and Safety Executive (HSE) prosecuted Azhar (aka Aziz) Mohammed (trading as ANS Bodyshop and AMS Spares) for failing to comply with improvement notices served on 1 May 2009. Meanwhile Izhar Ul Haq (trading as BM’s Repair Centre) and Asif Butt (trading as Hydeny Autos) were convicted and sentenced for a similar offence respectively on 23 July and 23 August 2010. All three companies are based on neighbouring sites in Empress Road, Luton. Mr Butt and Mr Mohammed admitted breaching Section 21 of the Health and Safety at Work etc Act 1974 for failing to act on the improvement notices. Mr Butt was fined £500 and ordered to pay costs of £742.40 while Mr Mohammed was fined £1,500 with costs of £742.40.
Best Practice Guide No 8 – Selection and use of plug-in socket-outlet test devices Work on updating the Best Practice Guide on connecting microgeneration systems to domestic electrical installations (No 3) commenced in December, in association with a number of other interested parties. Revision of the Best Practice Guide on recommendation codes for domestic electrical installation condition reporting (No 4) will follow in due course, and will take into account the new report form that is likely to be included in Amendment 1 to BS 7671: 2008.
that the company had manufactured and supplied faulty cables during 2009 to the UK market.
As reported in the last issue of Switched On, batches of affected Altas Kablo cable originally dated from February 2010, however recent cable testing clearly shows
Mr Ul Haq pleaded guilty to two breaches of the same section. He admitted failing to act on the improvement notices and failing to arrange maintenance examinations of a car hoist which was found to be defective. He was fined £2,000 and ordered to pay costs of £742.40.
SwitchedOn Issue 19 Winter 2010
news AFTER THE FLOOD HAS GONE - A SAFETY GUIDE BEFORE MOVING BACK IN fter months of living away from home, Angela Beauchamp and her three children have to start again. Following torrential rain in June 2010, the domestic flood they experienced covered many electrical goods in water and she is aware that many of them may have to be replaced to avoid serious injury. The need to ‘get back to normality’ is prevalent, although safety is a key concern for Ms Beauchamp; she has considered how she will redecorate the house, however the safety strategy is more complex and very daunting. A flood is not usually foreseen and therefore it can be difficult to plan for its aftermath. Much like many Britons who have suffered the devastation of flooding, Ms Beauchamp was certainly not expecting this to happen to her family home.
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sure the property is safe before to switch on the lights or use • Make • Attempt you enter. candles to guide you. a torch at hand when entering the on any electrical appliances in • Have • Switch property. the areas affected by the flood until they have been tested and assessed as off the electricity supply at the • Switch safe by a registered electrician. fuse box, if it is safe to do so. any electrical repairs or • Attempt for other services, such as gas, • Arrange connection of temporary electrical to be turned off by the service providers. The electricity and gas supplies should remain off until you are advised that it is safe to turn them back on. your insurance company (and • Contact your landlord, if applicable) to tell them what’s happened and to get advice and take instruction. a registered electrician to assess the • Use condition and safety of the electrical wiring in the property, as well as fixed and portable electrical appliances affected by the flood.
The ESC has compiled two useful lists to assist homeowners and tenants when re-entering their homes following a flood:
DON’T...
professional advice about the • Seek restoration of your property before clean up commences.
supplies yourself.
any exposed wires – they may • Touch still be live. to clean up until you are sure it is • Start safe to do so. Phil Buckle, director general at the Electrical Safety Council warns: “Anyone who has suffered a flood in their home must consider the damage that may have been caused to their electrical wiring, sockets and electrical appliances. Flood-damaged electrical goods and installations may be dangerous and anyone concerned about their safety should ask a registered electrician to assess their safety and condition before use.”
The Electrical Safety Council has produced a leaflet advising how to deal with flood damaged property which is available to download from www.esc.org.uk. For further advice and information call the Council helpline on 0870 040 0561
WEBSITES NOW INCLUDE SIGN LANGUAGE recent survey from The National Deaf Children’s Society (NDCS) revealed the growing void between the GCSE exam results of hearing and non-hearing students. The study showed that 71% of deaf children gained fewer grades at A*-C at GCSE; significantly less that their hearing counterparts. As part of its commitment to accessibility and education, the ESC is now providing sign language on both of its educational websites for children.
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TwoThirtyVolts.org.uk, which is aimed at 1117 year olds, and SwitchedOnKids.org.uk, developed for 7-12 year olds, are popular educational websites that provide a range of information about the benefits and dangers SwitchedOn Issue 19 Winter 2010
of electricity. As well as providing videos and games for children, the websites include a variety of resources for teachers, including lesson plans and revision notes. Both of these sites now host full British Sign Language (BSL) throughout, to ensure that deaf children can easily access the learning resources they provide. Many deaf children have difficulty learning to read and write because it is a skill so closely linked with speech and sound. Consequently, most web-based educational resources for children are not accessible to the majority of the deaf community. It is this lack of accessible information that some believe is affecting the education of deaf children in the UK.
Commenting on TwoThirtyVolts and SwitchedOnKids, Tyron Woolfe from the NDCS says: “The two websites are fantastic resources for young deaf people. The NDCS welcomes organisations and companies actively working towards making information accessible to deaf young people, and these websites developed by the ESC are an excellent example of such a practice. Deaf young people can find out how to keep themselves safe, pick up fun facts and get information about careers in electricity. It is rare for any organisation which isn’t deaf-centred to provide full BSL translation on their websites, and we encourage other organisations to follow the ESC’s example.”
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letters Testing times Extension leads While admiring the thorough for RCDs While employed with one of our leading supply companies, I carried out an audit on well over 100 installations fitted with RCDs and earth tripping devices and found around 50% would not operate. Admittedly, some of these were of the old voltage operated type. Following this audit, I raised the question: “What is the solution to better RCD safety?” Regular testing was never carried out and here lies the real issue as to how we are going to educate the public into the need to regularly test their RCDs. Everyone is surrounded by so many electrical devices, such as computers, games, TVs, DVD recorders, microwaves, clocks etc, which all rely on a continuous power supply for 24 hours of the day. With so much going on around them, as well as bringing up the children, the last thing on their minds is the periodic testing of their RCDs. Even if they do find the time for this, then a large number of electrical devices will have to be restarted or re-timed, and that is before they have shutdown their TVs, computers and Playstations before the tests. The general public does not perceive an immediate danger in electrical installations. As for testing, to them it is not important. Their only concern appears to be to have a continuous supply available 24 hrs a day. Reliability in manufacture, I feel, is really the only answer but even that is not a guarantee that the device is going to operate when called upon to do so. David Le Clercq MIET MCMI Bournemouth
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work on four-way extension leads described in the autumn issue of Switched On, I’m amazed that I could find no reference to the problem’s most obvious cause. That the regulations permit a 13A plug feeding a four-way extension to be protected by an internal fuse required not to fail until the current exceeds 20.8A, (let alone 24.7A for 30 minutes) is clearly inviting trouble from overheating - 4.8 kW from a 3kW source! This, surely, is the real problem that has to be addressed. Tom Jacobs Twickenham
Electric gates I read your article on the dangers of electrically operated gates in Issue 18 of Switched On. While not disagreeing with the recommendations contained in this article, there seems to me to be one glaring omission to the safety requirements for this type of equipment. It should not be possible for an actuating pushbutton switch to operate this equipment without being held by the operator while the gates are opening or closing. At present it is allowable for a driver of a vehicle to operate a radio remote control from within a car and drive away. If a child then obstructs the moving gate it does not stop and there is a tragedy. If drivers needed to stay within close proximity and maintain the command signal until fully open or closed, then the deaths that have occurred may have been avoided. Perhaps the ESC should take another look at this issue. William Budd Budd Electrical Cardiff
EU Injury Database On the back page of Issue 18 of Switched On you refer to the EU Injury Database and how it might provide data missing since the demise of the UK Home and Leisure Accident Surveillance System. You say the EU IDB covers eight countries but you do not say if the UK is one of those countries covered. If it is not, I fear that the IDB will be of limited value. Even with harmonisation, UK installation practices are so different from most other EU states as to question their relevance. We need UK statistics to prove (or sometimes disprove) assertions made about electrical safety in the UK.
Sweden. These were chosen because they have ‘similar’ cultures to the UK – the UK was not included simply because no injury statistics have been available since 2002 when the home and leisure injury databases ceased to be supported by the government.
I doubt the wisdom of extrapolation from a sample of 84 hospitals in eight countries to the whole of Europe, still more in applying it to the UK. How many of those 84 hospitals are in the UK?
The 84 hospitals were selected from the eight countries mentioned above so none of those were from the UK. It would have been preferable to refer to UK injury statistics but they simply don’t exist, even though there is an EU Regulation requiring the UK to have a system for collecting injury data. A pilot scheme for collecting injury data was set up in Wales but it was never completed – other pilots in the UK have not even started.
N C Friswell Retired electrical safety inspector, formerly with the HSE The ESC replies: The eight countries used in our survey were Austria, Cyprus, Germany, Latvia, Malta, Netherlands, Slovenia and
It is fair to say that installation practice may vary in EU member states, but we had to refer to something because the UK home and leisure statistics are now too far out of date to rely on, especially with the ever-growing range of electrical products on the market.
Letters 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.
SwitchedOn Issue 19 Winter 2010
news PLUG INTO SAFETY CAMPAIGN CONTINUES APACE
Electricians’ packs available NOW
he Plug into Safety RCD campaign continues to garner coverage in a range of media outlets. Following on from the launch in May, the ESC has continued to approach both consumer and trade media to keep a continuous ‘drip-feed’ of information coming through.
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“We know that to really get a message across to an audience, you can’t just say it once and hope that people remember. You have to repeat it, over a period of time, in different ways, to try and embed the information,” explains Angela Murphy, ESC media manager. “To be really effective, a campaign needs time and if its objective is to help bring about behavioral change, it can take years.” To take advantage of the summer seasonal focus, the Council initially targeted home and gardening publications - both in print and on-line - with a range of electrical safety tips emphasising RCD protection. Among the coverage gained are items in magazines such as Period Living, Traditional Homes and Garden News.
safety information, it also contains detachable, blank business cards - urging consumers to install RCD protection - which contractors can leave with clients after a house-call. This is just one of the ways in which the Council is supporting industry in encouraging householders to install RCDs and take on board basic safety messages. To supplement this, the Council has also been pursuing coverage in key stakeholder publications, including Fire and Rescue Services magazines and local council websites. “There is no doubt that we have been able to achieve strong media coverage but the life-blood of any campaign is case studies – people’s real-life stories,” adds Angela. “We have been developing a number of these to use with the Plug into Safety campaign but we are always looking for more. So, if you, a friend or family member, or even a client, have a story to tell about how an RCD saved a life or prevented an injury – or could have, if one had been used – we would love to hear from you.”
The ESC has produced an ‘electrician’s pack’ designed to help electricians put forward the case for RCDs in their conversations with homeowners. Each pack contains 50 ESC leaflets that include information on the risk of death and injury that electrical accidents can pose and how installing an RCD in a consumer unit can offer full protection to households and families. These packs are available at many wholesale outlets throughout the UK and are free of charge. Packs can be obtained from the following stores: Arc Electrical CEF (City Electrical Factors) Denman's JH Leeke and Son QVS Rexel Screwfix Trade Counters TLC Wilts Wholesale We would like to thank our wholesale partners for their support. Please visit www.esc.org.uk/plugintosafety to find your nearest stockist. We welcome your feedback on the packs and the leaflets and to hear your views on the campaign itself. Please email us at plugintosafety@esc.org.uk
Of course, it is also vital that the ESC keeps the industry informed and involved in its activity; and the Council has achieved a spate of coverage in the trade press, particularly with the launch of the Electrician’s tool-kit (see box). Articles and news items have appeared in, to name a few, Professional Electrician, Electrical Digest and Electrical Contracting News. The toolkit is specifically designed to help contractors communicate the benefits of RCD protection to customers. In addition to SwitchedOn Issue 19 Winter 2010
If you have a story to tell, please contact Angela at: angela.murphy@esc.org.uk
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news SUCCESSFUL PARTNERS ANNOUNCED FOR THIS YEAR’S FIRE SAFETY FUND AWARDS ollowing the success of the Council’s Fire Safety Fund last year, in September it announced the successful projects in the 2010-11 Fire Safety Fund Awards scheme.
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Of the 169 applications received, 23 organisations throughout the UK were chosen to share over £100,000 of funding to support electrical fire prevention schemes through partnership working at local level. With around half of all domestic fires in the UK caused by electricity (either electrical faults or misuse of appliances), this is a key issue for the ESC. This year’s successful projects will cover a range of activities including electric blanket testing; products testing and replacements; raising awareness of electrical safety by delivering training; and assistance with the refurbishment of a safety vehicle which will be used at local community safety events. The judging process was rigorous and each application was assessed against a set criteria that, among other things, included the need to demonstrate that projects would effectively support fire prevention at local level; and that they would reach high risk and/or vulnerable people in their community such as the elderly or the young.
ESC HELPS TO CREATE SAFER MIGRANT COMMUNITIES
All the schemes are locally based in order to support their communities. For example, Wandsworth Council’s initiative, aimed at young carers, was submitted in response to two fire incidents in the area. These revealed a need to run training sessions, in partnership with Fire & Rescue Services, for young carers in order for them to learn about electrical safety in the home and share this information with other members of their household. Funding was also awarded to The Risk Factory, a safety organisation based in Edinburgh. It looked at figures from the Scottish Community Fire Safety Survey that stated that 47% of victims of accidental dwelling fires are over the age of 60. Their project, working in partnership with Lothian and Borders Fire & Rescue Service, plans to develop a new awareness programme aimed at the elderly, which will use real life scenarios to highlight everyday electrical dangers and hazards within the home and provide guidance on how to avoid them. To find out about the full range of projects supported this year by our Fire Safety Fund, visit www.esc.org.uk/business-andcommunity/fire-safety-funding
oland’s main statistical office says that 1.95 million people, or 3.3% of the population, left their country to work abroad between the country’s entry into the EU in 2004 and the end of 2006. Many of those people ended up working in the UK.
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Lancashire became home for a number of Polish migrant workers, typically sharing rented rooms in so-called Houses of Multiple Occupation (HMOs); houses or flats let to three or more tenants. This soon became a focus for concern for the Lancashire Fire and Rescue Service, initially because of the heightened fire risks attributable to overcrowding, but more was to follow in relation to incompatibility between UK 13amp power sockets and the plugs on electrical appliances brought into the country by the workers.
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Following a terrible fire in an HMO in Germany in which Turkish immigrants died, Lancashire’s chief fire officer, Peter Holland, speaking on BBC TV’s 10 O’clock News said: “Though many HMOs are well run and incorporate proper fire precautions, it is sadly the case that a number are not and we have had a number of fires in Lancashire in which firefighters have saved the day and rescued people, but have discovered an atrocious lack of fire protection measures in the property.” Already a new threat to fire safety had emerged, explained by the community liaison worker, Magdalena Stryjewska, appointed by the Lancashire Fire and Rescue Service to head up their fire prevention efforts with migrant workers. “Polish workers were bringing electrical equipment with them, such as mobile phone chargers, SwitchedOn Issue 19 Winter 2010
news ESC PUBLISHES 2009/10 ANNUAL REPORT he Electrical Safety Council (ESC) has published its 2009/10 annual report revealing that the charity is now paying closer attention to evidence-led campaigning and impact evaluation. In addition, the Council continues to give guidance on installation and product safety while making grants available to vulnerable groups.
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According to Phil Buckle, director general of the ESC, the charity made good progress against its strategic objectives and undertook major operational changes for the period under review. These changes will help the ESC cement its position as a leading campaigning charity and technical authority on all matters relating to electrical safety. “The changes have created several benefits for the organisation, including a new technical development function and greater coordination of activities. This has helped to focus the skills and energy of the team into areas such as product safety,” says Phil. He notes that the Electrical Safety Council is now well on the way to becoming “a charity that is more forward thinking, strategic and better able to prevent accidents caused by electricity in the UK.” In the meantime, chairman Bill Wright lauds the ESC for its achievements, noting that an extensive review of the governance structure and policy has been undertaken to allow the
equipped with two-pin plugs,” she said. “We discovered that they were forcibly inserting them into UK 13-amp power outlets, often jabbing a screwdriver into the earth slot to trip the sprung-loaded shields over the live and neutral slots. “In some cases they’ve bought converters marked FOR SHAVERS ONLY instead of a proper EU-to-UK converter and after running a higher power appliance than a shaver through it, have complained that the device has stopped working after just one use! I realised too that the concept of fused plugs for appliances was new to them. “The Electrical Safety Council stepped in to help us tackle these issues, generously donating converter plugs, including ones incorporating a fuse, to make it possible for people to use their electrical equipment safely. SwitchedOn Issue 19 Winter 2010
Council to deliver positive outcomes for its beneficiaries. According to Bill, key governing documents have been modernised and improved. “To ensure we are fit for the future, the Board of the Electrical Safety Council has started to undertake a full review of the current strategy. This will include responding to major external drivers, such as the growing environmental agenda and the potential impact of current financial realities,” he affirms. In terms of strategic priorities, the ESC says it spent the last year focusing on four strategic priorities - building a robust evidence base to ensure that campaigning and technical activity of the Council is targeted; making electrical installations safer; providing direct support and grants; and improving its strategy for product safety. The ESC also undertook research in key areas such as public attitudes to electrical safety and product safety.
a new educational website on • Developing electrical safety for teens www.twothirtyvolts.org.uk over £200K in direct support • Awarding and grants to vulnerable groups an online buyer’s guide to • Launching encourage safe shopping online with Trading Standards Institute • Partnering to develop a secure online system to share information about electrical products and wider safety issues a new database with product • Creating recalls
Among the achievements highlighted for 2009/10 were: a Landlords’ Guide to Electrical • Publishing Safety in England & Wales and distributing over 20,000 copies a safer rented homes campaign • Running to help raise landlords’ awareness of their obligations and make tenants aware of their rights to a safe home
“To help us get the message across, the ESC have made stocks of their leaflet Adapt your electrical appliances for safe UK use freely available to us. I mostly make use of it in its Polish version, Przystosuj urzadzenia elektryczne do bezpiecznego uzytkowania w Wielkiej Brytanii, which I talk through and hand out during my fire safety talks in Polish to groups at community centres and other gatherings.
The 2009/10 annual report and financial statements can be downloaded at www.esc.org.uk.
Association of the United Kingdom, Peter Holland concludes: “I see Magda’s project and the Electrical Safety Council’s central role in it as wholly consistent with the outstanding work that the ESC does in partnership with Fire and Rescue Services in the UK. I am profoundly grateful, not least because of the lives and properties that have undoubtedly been protected due to the invaluable support the ESC has provided.”
“Without question, the leaflet is an essential resource and together with free converter plugs for the neediest, helps me reduce the likelihood of fires and electrocution in Lancashire homes.” Newly elected as the president of the Chief Fire Officer’s
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Green Goo continues nuisance to househo to electrical installer The phenomenon commonly referred to as ‘green goo’ is one that has affected electrical installations ever since the late 1960s and it seems that it is a problem that could be with us for some time to come. A recent increase in the number of reports received by the Electrical Safety Council indicates that the problem caused by green goo remains ever-present. The reasons for the increase in reports may be related to the economic downturn, in particular the growing trend for householders to improve their home rather than to move house.
What is green goo? The insulation on flat twin and earth cable is made from polyvinyl chloride (PVC) to which a plasticiser, di-isoctyl phthalate is added during manufacture to make the cable relatively pliable to aid cable installation. Green goo is a side effect formed during the chemical reaction between the plasticiser of the insulation and the copper conductor that occurs when the conductor temperature nears its maximum operating temperature (typically 70 oC). At such temperatures the plasticiser can leach from the cable causing the insulation to become sticky to the touch initially but as the leaching continues the cable insulation becomes hard and brittle. The problem was most prevalent between 1965 and 1971 when an antioxidant was introduced into the manufacturing process. Cable manufactured since the mid 1970s does not have the same inherent defect.
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Effects on electrical insulation If the green goo is restricted to that of leaching of plasticiser then evidence suggests that, although unsightly, the electrical integrity of the cable insulation will not be reduced if the cable is not disturbed. However, if the green goo is severe it can result in the cable insulation becoming brittle whereby the insulation quality may be significantly impaired, which could lead to electrical faults, including an increased risk of electrical fires. Consequently, where green goo is discovered an insulation resistance test should be carried out to determine the extent of the affect on the cable insulation.
SwitchedOn Issue 19 Winter 2010
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s to be a olders and rs The green goo may also have detrimental effects on accessories (in appearance and functionality terms) and their decorative finishes.
that those persons working with affected cable adopt good personal hygiene practice by washing their hands before eating or drinking to prevent inadvertent contact and/or ingestion of green goo.
Solutions Unfortunately, where an electrical installation is seriously affected by green goo, the only practicable solution is to rewire the premises and replace any related affected electrical equipment. Simply replacing affected electrical accessories and equipment and redecorating is likely to be only a temporary improvement measure and the green goo will evidently re-occur. The Electrical Safety Council advises that all such remedial work is undertaken by a registered electrician.
Health risks Contrary to belief, green goo is not a carcinogen. However, being in contact with it may lead to possible ill-health effects, such as skin dermatitis and/or rashes. The advice from the Health and Safety Executive is that precautions should be taken to prevent skin contact and ingestion of the substance. This can be easily achieved through the use of protective gloves and clothes, such as disposable coveralls with hood to prevent contamination of clothing and hair, for example. Such precautions should be especially followed while removing and disposing of any affected cable. Consideration should also be given to ensuring
SwitchedOn Issue 19 Winter 2010
Environmental considerations Electrical installers should determine whether the requirements of the Waste Electrical and Electronic Equipment Regulations (WEEE) are applicable when disposing of affected cables or accessories (socketoutlets, lighting switches or ceiling roses, for example). The ‘crossed out wheelie bin’ symbol found on many electrical items means that they should not be put with normal household rubbish. Instead, take the affected waste to a recycling facility that accepts electrical products.
problem “wasThemost prevalent between 1965 and 1971 when an antioxidant was introduced
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Although electric cable does not generally fall under the requirements of the WEEE Regulations it should be recycled safely. Where doubt exists on how to dispose of electrical and electronic equipment contact should be made with your local authority who will be able to advise you on how safely to dispose of the item and provide you with the location of your nearest recycling centre.
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news SMART THINKING FOR THE SMART METER PROGRAMME he introduction of the smart metering programme will see smart meters for electricity and gas being installed in all domestic premises in the UK by 2020 (or sooner if plans for an accelerated programme are adopted). This will arguably be the biggest reform of the UK energy market since the switch to North Sea gas in the 1970s, and will involve the installation of 46 million new electricity and gas meters in 26 million homes across the UK.
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For use with gases consisting mainly of Methane excluding LPG Q max 6m2/hr Q min 0.04m2/hr P max 75 mbar
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regard to ensuring the electrical safety of householders and of themselves.
Ascertiva Group, Institution of Engineering Technology, Sterling Power Group
While a lot of activity is being carried out by many organisations to help ensure the smooth and successful implementation of the smart meter programme, there remains work to do.
The event provided a platform to explore ways for building upon the good work already initiated by Ofgem and the energy supply industry for maximising the opportunities presented by the smart metering programme – a once-in-a-lifetime event, and how best to protect householders and meter installers alike.
In October, as a move to bring together many of the smart meter stakeholders, the Council invited senior representatives from energy suppliers, meter operators, distributors, enforcement bodies and central government to take part in a round-table event to debate how all our efforts could be united to tackle the opportunities and barriers associated with the installation of smart electricity meters.
Under the gas Act this meter is the property of the Gas Supplier to these premises
Full and frank discussions were held on topics including available Standards associated with installer competence and those for installation practice, options available for improving safety through the smart meter specification, and how best to communicate safety messages to the consumer.
ACCESS ONLY BY AUTHORISED PERSONNEL
The Electrical Safety Council believes that, with the co-operation of the electricity supply industry, there is an opportunity to improve electrical safety in some of the UK housing stock. But the ESC has concerns as to how the competence and workmanship of the installers being trained to carry out this major programme will be assured with
The event was chaired by Ann Robinson from U-Switch, who welcomed participants representing the following organisations: Ofgem, Health and Safety Executive, Energy Retail Association, Energy Networks Association, Fire and Rescue Services, MOCOPA, British Gas, E.on, NPower, Unite, Siemens Metering, National Skills Academy for Power, Electrical Contractors’ Association,
The debate concluded with proposals that are likely to result in the Electrical Safety Council taking a leading role in developing safety information for dissemination to householders during the smart meter installation process. It will also see the Council continuing to play its part in helping to ensure that the safety interests of consumers are fully considered.
ELECTRICAL TRAINING FOR FIRE & RESCUE SERVICES
W
ith government statistics showing that approximately half of all accidental domestic fires in the UK are caused by electricity, hands-on training for front line staff is vital.
renowned. Twenty-six people attended the event including all 14 fire investigation officers from Hertfordshire FRS, as well as representatives from fire services in Norfolk, Suffolk, Cambridge, Bedfordshire and Essex.
To help address this issue, the Electrical Safety Council recently teamed up with Hertfordshire Fire and Rescue Service (FRS) to sponsor a training course on the fire investigation of electrical incidents.
Steve Curtler, product safety manager at the Council also attended the course and used the opportunity to share information about the work of the Electrical Safety Council and the partnerships it develops to support grass roots community fire safety projects.
The two-day course, attended by fire investigation and scenes of crime officers, covered a range of topics, from basic electrical theory through to arc mapping and point of origin indicators, with emphasis on practical exercises. The course was opened by Hertfordshire’s area commander for operations, Doug Robinson, and led by Dr Nick Carey, a fulltime fire investigation officer for the London Fire Brigade. He is the electrical fires expert for the FRS UK-wide and is internationally
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reduce them. This kind of collaboration shows where partnership working can really have an impact. By supporting the FRS in this way, we help them to help us reduce the economic and emotional losses caused by electrical fires.” The Council works on a range of initiatives to reduce the number of electrical fires in the UK. One of these, the Fire Safety Fund has to date awarded £220,104 to community projects to improve electrical fire safety.
Phil Buckle, director general of the ESC, comments: “The need for specialised training is evident – the government statistics speak for themselves. By enabling rescue services to extend their understanding of electrical fires, we help them develop best-practice techniques and approaches to dealing with them. It should also help to improve accuracy of fire reporting, which in turn will enhance statistical data on electrical fires and assists us in determining how best to SwitchedOn Issue 19 Winter 2010
news THE COUNCIL AT CONFERENCE his autumn, the Electrical Safety Council attended the Labour and Conservative Party Conferences, taking its RCD and fire prevention agendas to key opinion formers and policy makers in the national political arena. The background to both events, held in Manchester and Birmingham respectively, was of some historical significance. Labour’s conference was ‘book-ended’ by Ed Miliband’s appointment as party leader and his brother David’s subsequent resignation from the front bench. The Conservative convention was their first in government since 1996 and came just ahead of the much-anticipated Comprehensive Spending Review in October.
T
The ESC had exhibition stands at both conferences, with our RCD campaign ‘Plug into Safety’-inspired design highlighting the dangers caused by carrying out DIY or gardening without RCD protection. The Council asked MPs and local government councillors to sign a pledge in support of its objectives; to encourage greater use of RCDs, and to introduce local registration and periodic inspection requirements for private landlords. In all, the Council spoke with around 500 people at its stand over the two events. In Manchester, five MPs and 11 elected
SwitchedOn Issue 19 Winter 2010
councillors signed the pledge and at the Tory conference there were several high profile visitors to the stand. These included cabinet ministers Caroline Spelman (Secretary of State for Environment, Food and Rural Affairs) and Cheryl Gillan (Secretary of State for Wales). The ESC also held fringe events at each conference, with a small, select group of key politicians and stakeholders invited. The events consisted of a dinner, followed by discussions on the theme of the impact of electrical fires on UK property. Conversation took place in a relaxed and informal atmosphere, with Council guests invited to respond to issues raised by ESC director general Phil Buckle.
Safety campaign, particularly from a prominent Conservative MP. He likened the campaign to the government’s longstanding and successful Fire Kills initiative, which has dramatically increased the number of smoke alarms in UK homes. He suggested that Plug into Safety should follow a similar approach by engaging and liaising with fire brigades – something the Council already does with its Fire Safety Fund. He also suggested that greater publicity was needed on the issue, and that there could be scope for the Department of Communities and Local Government to support a national initiative. The Council hopes to foster new partnerships that can add value to the existing relationships it has with numerous UK Fire Services, as well as industry, retail and community groups.
The discussion incorporated a range of different views on how domestic fires might be reduced. At the Labour conference, there was a consensus that more regulation is needed - particularly in the privately-rented sector - where some rogue landlords fail to protect their tenants from the real risks of fire. One of the parliamentary guests, an influential backbench MP, suggested that this area “cannot be over regulated”.
Overall, reactions to the ESC agenda were positive and the Council fully expects that the contacts made and meetings held will prove valuable in helping it to further the interests of consumer safety in the UK. If you would like to know more about how the ESC is helping to influence Westminster’s home safety agenda, please see www.esc.org.uk for more information.
At the Conservative event there was general approval for the objectives of the Plug into
Phil Buckle (ESC director general) and Martyn Allen (ESC head of technical development) with Emily Thornberry (MP for Islington South and Finsbury)
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technical Spotlight on…the JIB Steve Brawley, chief executive of the JIB, brings readers of Switched On up to speed with current initiatives. The Joint Industry Board for the Electrical Contracting Industry (JIB) serves the electrotechnical industry by setting standards of employment and occupational competence. Since its inception in 1968, the JIB has evolved to meet the ever-changing needs of a technologically driven industry. Some 1,600 companies are members of the JIB, employing around 16,000 employees across the electrotechnical industry and over 100,000 individuals hold valid Electrotechnical Certification Scheme (ECS) cards issued by the JIB to accredit their occupational competence. The JIB provides a range of member benefits and has recently introduced a number of initiatives to benefit the sector. Current JIB services to the electrotechnical industry include: Electrotechnical Certification Scheme (ECS), which is jointly • The owned by the JIB and the Scottish JIB, offers every individual in the industry the opportunity to accredit their qualifications and occupational competence at all levels, from Labourer to Manager. The Scheme is affiliated to the Construction Skills Certification Scheme (CSCS), thus providing the card holder with access to sites which require a CSCS-affiliated card. In recognition of the increasing demand for ‘green’ electrical skills - including the installation of photovoltaic panels, solar thermal, ground and air source heat pumps and wind turbines - skilled ECS card holders will soon be able to display their renewable credentials on their card to demonstrate competence in environmental technologies. JIB Further Education Fund provides financial assistance to • The individuals who want to develop their skills in the electrotechnical industry. The training fund can assist employees of JIB companies, as well as apprentices at non-JIB member companies, to enhance their careers by extending their vocational education, benefiting not only themselves, but their employer and the industry that they serve. If an individual’s employer is an ECA member, they can also make an application on their behalf for full funding for certain courses from the ECA’s training fund. Unite members can, in addition, apply for a bursary to support their studies. Since its inception, the JIB has helped fund the NVQ Level 3, BTEC National Certificates, BSc/Foundation Degrees in Building Services, HNCs, ONCs, the City & Guilds Level 3 in Process Technology and the City & Guilds Level 2 in CAD (2D). The application process is very straightforward and full support is provided by the JIB staff. The application form can be downloaded from the JIB website.
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The JIB runs an Adult Craft Training Scheme assisting nonqualified adults to achieve skilled status as an electrician through a flexible training route. The Adult Craft Training Scheme is not a replacement for a formal apprenticeship but works alongside the JIB Apprentice Training Scheme to allow experienced but unqualified operatives within the electrotechnical industry to achieve craft status.
The JIB provides a Trust-based, industry-wide defined • Pensions. contribution pension scheme. With assets of c£200m, the Scheme is designed to be a low-cost, low administrative burden scheme enabling individuals to accumulate retirement funds in a taxefficient manner in partnership with employers. Organisations belonging to either the JIB or the ECA can participate in the Scheme and extend membership to their workforces. Employers are required to pay a minimum contribution of 2.5% of member’s gross earnings, matching the member’s contribution. JIB has appointed Capita Recruitment Vetting Services to • The provide Criminal Records Bureau (CRB) checks for people who need to work in establishments which house vulnerable people, such as schools, hospitals and care homes. Successful applicants are given a photo-ID card to verify they are permitted to enter such properties. Applicants benefit from an online processing system to allow for faster turnaround times and lower costs. The photo-ID card is an optional extra and applicants can simply receive a formal letter confirming CRB clearance if a card is not required. For more information about the JIB please visit their website at www.jib.org.uk. Further information on ECS cards can be found on the ECS website at www.ecscard.org.uk.
SwitchedOn Issue 19 - Winter 2010
technical
Have you ever been asked...
Why did the RCD trip when I was working on a circuit isolated by a single-pole device
Installers are sometimes puzzled by a problem that can arise when working on a final circuit that has been isolated by means of a single-pole outgoing protective device (circuitbreaker or fuse) in the consumer unit, such that only the line conductor is isolated. Typically, at some stage, the installer does one of the following: a. lets (or makes) the neutral and protective conductor of the circuit touch, such as by twisting them together to push the cable into the entry hole of an accessory box; b. lets the neutral conductor touch metalwork, such as a water pipe, that is connected to the main earthing terminal of the installation by a bonding conductor, or c. touches the neutral conductor with a hand. The installer doesn't notice anything wrong, and maybe even finishes off the connections, so that the neutral is no longer in contact with any of the ‘earthy’ items in (a), (b) or (c). But, shortly afterwards, someone complains about the TV or the fridge, for example, going off. On investigating, the installer finds that the RCD protecting the circuit has tripped. “Not me”, he (or she) cries; “what I was working on was isolated”. Then he starts to worry. “Did I do something wrong?
?
Is the circuit incorrectly labelled or cross-wired? It must be ‘nuisance’ tripping,” he thinks, reducing his faith in RCDs. Of course, what happened was that, when the neutral touched the protective conductor or other earthy item, this created a parallel path for a proportion of any neutral current flowing in the other, unisolated, circuits. This current bypassed the current balance core of the RCD, causing the RCD to trip. Figure 1 shows an example of this where the neutral and protective conductor have touched. So it is not really ‘nuisance’ tripping in the normal sense of an accumulation of earth leakage current or a transient voltage spike. The only way to avoid the tripping problem is to work with the circuit isolated by a double-pole device, such as the main switch of the installation, or with the neutral of the final circuit disconnected at the consumer unit. The issue described above is a problem particularly in TN systems. However, it could also occur in a TT system, if the earth electrode resistance is low enough to allow the tripping current of the RCD (perhaps as low as about 20 mA) to flow as a result of the small voltage that typically exists on the consumer unit neutral busbar due to voltage drop in the neutral conductor of the supply network. In any event, it should be remembered that the isolation requirement for a TT system is always that both the line and neutral conductors should be isolated (Regulation 537.2.1.1 refers).
Figure 1 – Contact between neutral and protective conductor (cpc) of circuit being worked on creates parallel path for a part of neutral current flowing in other circuits (TN-C-S system shown).
Note. A modern consumer unit would normally have more than one set of busbars. Other sets are omitted for clarity SwitchedOn Issue 19 - Winter 2010
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technical
ESC investigates consumer concerns over compact fluorescent lamps Low energy compact fluorescent lamps have been available for several years and are now viewed by consumers as a viable alternative to the regular incandescent (tungsten filament) lamp. They are available in several different designs covering common domestic installations, and consumers are being encouraged to replace incandescent lamps with low energy compact fluorescent lamps, often as free, or heavily discounted, promotional items. However, the Electrical Safety Council has received many enquiries from consumers concerned about scorching and discolouration of compact fluorescent lamps after relatively little usage as well as near or at the end of the lamp’s life. In some cases the overheating has been perceived as serious, with one incident resulting in a small fire contained within the lamp. Also, the wide range of lamp wattages and their stated equivalent wattage when compared with incandescent lamps is a cause of some confusion. Subsequent research carried out by the Council suggests that particular installation conditions may be a contributory factor to the overheating of lamps. As part of the Council’s electrical product safety screening programme, it commissioned an independent laboratory to carry out limited safety and thermal endurance testing on a selection of commercially available low energy compact fluorescent lamps. Sample election
Product testing Each lamp type was subjected to limited testing under the safety requirements standard for self-ballasted lamps, BS EN 60968: 2000. Thermal endurance testing was also carried out under the general requirements standard for luminaires, BS EN 60598-1: 2008. Each lamp was tested in two luminaire types. The first being a commercially available bulkhead and the second, a ceiling-mounted pendant having a frosted glass shade. After consideration of possible installation conditions, the test programme consisted of the following: BS EN 60968: 2000
• Visual inspection of marking requirements • Resistance to flame and ignition by application of glow wire • Single fault condition for eight-hour duration at 253 V BS EN 60598-1: 2008 test under normal operation at 240 V and repeated at • Thermal 254 V with temperature measurements recorded at specified locations
Six self-ballasted compact fluorescent lamps with a bayonet (B22) lamp cap were randomly selected and purchased. The lamps ranged
Lamp design
from a stated 11 W through to 25 W, with an equivalent range of 60 W through to 125 W when compared with traditional incandescent lamps (see table below).
endurance test for 240 hours at 264 V, cycled 21 hour • Thermal lamp on and 3 hour lamp off
Stated wattage
Equivalent incandescent lamp wattage
Expected lifetime in hours
Candle with inner spiral tube
11 W
60 W
8,000
Traditional lamp with inner spiral tube
15 W
70 W
6,000
Multi straight tubes
15 W
75 W
10,000
Multi straight tubes
20 W
100 W
10,000
Spiral tube
20 W
100 W
8,000
Spiral tube
25 W
125 W
10,000
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SwitchedOn Issue 19 - Winter 2010
technical Product testing results
Conclusions
Two of the lamps failed to provide adequate markings including the absence of standard details on the lamp packaging. Of particular concern was the absence of the rated wattage.
The thermal endurance testing, particularly in the bulkhead luminaire, was an attempt to simulate the worst case installation that might lead to the reported overheating incidents. Discolouration of the lamp’s plastic moulding was apparent yet the lamps appeared to remain safe even until their eventual failure in operation.
A single fault involving a broken cathode was applied to each lamp. This fault is typically associated with an increased operating temperature resulting in potential overheating and deformation of the plastic moulding containing the ballast. Each lamp passed this fault condition test with no signs of enclosure discolouration or the emission of hazardous substances. The lamp mouldings were also subjected to a glow wire test to determine the material’s resistance to flame and ignition. All six lamps passed this test, which suggests that each lamp moulding material would have been suitably resistant to such conditions if overheating had occurred. Two of the four lamps installed in the bulkhead luminaire failed to achieve the thermal endurance test period of 240 hours. Replacement lamp samples are permitted during this testing and in some cases the replacement lamps lasted less than two hours before failing in a safe condition. In one case a lamp sample failed to start when first switched on and only one lamp type completed the test period without the need for a replacement sample. In most cases discolouration of the plastic moulding was apparent with the worst examples shown in Figures 1 and 2. No damage was observed to the bulkhead luminaire throughout the entire thermal endurance testing period. In contrast, each lamp type achieved the required thermal endurance test period when installed in the pendant and glass shade. Slight browning of the plastic moulding was apparent in some cases but not as severe as that observed during the equivalent bulkhead luminaire testing. Again, no damage was observed for the pendant and glass shade throughout the entire thermal endurance testing period. All of the lamp types passed the thermal test under normal operating conditions in each luminaire. Thermocouples were positioned at various points in and around the installation and all recorded temperatures were within standard limits.
Thermal testing under normal operating conditions resulted in no obvious signs of discolouration and recorded temperatures were within standard limits. No signs of overheating were reported for either luminaire during the testing programme. Nevertheless, the findings of the limited testing reveal significant variations in the stated operational lifetime in hours. In one case a lamp did not operate when switched on for the first time. In many cases lamps failed to operate after less than two hours under thermal endurance conditions. It is accepted that the testing places the lamps under stress, but the results suggest a potential quality and reliability concern particularly when the average claimed lifetime is 9,000 hours. Enquiries received through the ESC helpline suggest that there is some confusion as to whether the rated wattage of a compact fluorescent lamp, or its equivalent (incandescent lamp) wattage, should be considered when selecting a lamp so that it does not exceed the maximum rating of a lampholder. The equivalent wattage is based on lumens, or the measurement of how much light the lamp produces, and is provided on lamp packaging solely to indicate the equivalent light output of a compact fluorescent lamp compared with an incandescent lamp. Therefore, the wattage rating of the compact fluorescent lamp, not its ‘equivalent’ rating, should be used to ensure that the maximum wattage rating of the lampholder is not exceeded. As with all safety investigations, we will continue to monitor identified failures and commission further research and testing where appropriate. A copy of the test report is available in the ‘business and community’ section of the Council’s website www.esc.org.uk
Figures 1 and 2: Examples of discolouration of plastic moulding under test.
SwitchedOn Issue 19 - Winter 2010
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technical Assessing the maximum demand of a domestic electrical installation Maximum demand is one of the general characteristics of an electrical installation that Part 3 of BS 7671 requires to be assessed.We give some guidance on assessing the maximum demand for an installation of an individual domestic dwelling. The requirement to assess the maximum demand for an installation is given in Regulation 311.1 of BS 7671. The main purpose of the assessment is to help determine the rated current capacity required for the supply of electricity to the installation. To assess maximum demand, sufficient information is needed about the connected load, how the installation is likely to be used and any allowances for diversity that may be applied. Failure to allow for the
appropriate diversity could lead to a new electricity supply being oversized or an existing electricity supply being deemed inadequate. Furthermore, the economic design of an installation almost always means that diversity must be taken into account. For example, to comply with Regulation 553.1.7, an adequate number of suitably positioned socket-outlets are needed for mobile electrical equipment. Without allowing for diversity, a circuit having (say) fifteen 13 A socket-outlets would have a potential load of approximately 195 A. This is unrealistically large and exceeds the rated current capacity of the supply typically provided (60, 80 or 100 A). In practice, the load on the socket-outlet circuits of a dwelling does not depend on the
number of socket-outlets but on the particular items of currentusing equipment connected to them and simultaneously in use. Estimating demand A variety of methods exist that can be used for estimating the maximum demand for a dwelling. One example is the method described in Appendix H of IEE Guidance Note 1 – Selection and Erection. Another example is the method given in IEC document 64(Secretariat)254, the use of which is explained in the IEE Electrical Installation Design Guide, Section 3.5. We will look at the use of the following two methods to calculate the maximum demand. The method described in • Appendix H of IEE Guidance Note 1 – Selection and Erection
Table 1: Allowance for diversity to be applied to an individual household installation, including an individual dwelling in a block
approach based • onA judgmental engineering knowledge and experience. The use of other methods by a competent electrical installation designer is not precluded by BS 7671. Whatever method is used, the estimate will be approximate in most cases. IEE Guidance Note 1 The method described in IEE Guidance Note 1 uses the information in Table H2 of that publication for estimating the maximum demand for the distribution circuit supplying all of the circuits of an installation. Information from Table H2, applicable to an individual household, is reproduced in Table 1 for ease of reference. The allowances for diversity in Table 1 can only be a guide. They may need to be increased or decreased by the electrical installation designer, depending on the particular circumstances. Suppose that the electrical installation is to have a singlephase supply, provided by the electricity distributor, with nominal voltage 230 V and rated current capacity 100 A. The maximum demand of the installation is to be calculated using the method described in IEE Guidance Note 1, Table H, in order to establish whether the proposed 100 A capacity of the supply will be adequate. Table 2 details the current-using equipment and socket-outlet circuits of the installation and the associated values of connected load. Also shown in Table 2 is the application of demand factors taken directly from Table 1. The calculation of the maximum demand for the installation, using these demand factors, is shown in column 6. As can be seen from column 6, the calculated maximum demand
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SwitchedOn Issue 19 - Winter 2010
technical is just under 116 A. Therefore, on the basis of the method of calculation described in IEE Guidance Note 1, without any modification to the demand factors, it appears that the proposed 100 A capacity of the supply will not be adequate. Judgmental approach The installation designer may instead wish to make an assessment of maximum demand by applying engineering judgment. In this example, judgment is applied to the same installation as described in the previous example. To make an engineering judgment, the designer will need to understand: operating time profile of • the the loads coincidence or • the simultaneous operation of individual loads with other loads
seasonal demands of • the heating and cooling loads allowance, if any, for spare • the load capacity (must be agreed with the client). The designer may consider, for example, that the following allowances for diversity, which are different from those used in the method described in IEE Guidance Note 1 (and shown in Table 1 of this article), may be made with regard to socket-outlets and the electric shower. Socket-outlets. Assume that both ring final circuits will have similar operating profiles, such that a demand factor of 40 % could reasonably be applied to both circuits, to find the overall maximum demand of the installation. Electric shower. For the purpose of assessing the maximum demand of a household electrical installation supplied from the
public electricity network, it is reasonable to take the average of the maximum demand occurring over a 15-minute period. This is because the service cable, service cut-out fuse and distribution circuit cable (meter tails) take a certain amount of time to be heated up by the load current, and there will be negligible additional heating effects on the source of supply (the distribution transformer) due to the peak maximum demand in the installation within a 15-minute period. As the shower is unlikely to be used for more than (say) 12 minutes in a given 15-minute period, it is reasonable to apply a demand factor of 80 % (12/15ths) to the connected load of the electric shower. The allowances for diversity in this example are illustrative only and must be treated with some reservation. The actual allowances
that the installation designer makes must be based on his or her own judgment, taking account of the circumstances applying to the installation. The calculation of the maximum demand for the installation, taking account of the allowances for diversity described above for the socket-outlets and electric shower, is given in column 8 of Table 2, where it will be seen that the calculated maximum demand is just under 87 A. Therefore, on the basis of this alternative method of calculation, the proposed 100 A capacity of the supply can be expected to be adequate for the installation. Guidance on assessing the other general characteristics for this type of installation was given in an article on pages 16 and 17 of Issue 18 of Switched On (Autumn 2010).
Table 2: Calculation of the maximum demand by applying demand factors to connected loads of individual final circuits
Notes to Table 2: 1 The demand factors used in the table do not apply where the source of supply is a generator, such as a standby diesel-or-petrol-engine-driven generator 2 The current demand associated with the socket-outlet final circuits, to which diversity factors should be applied in order to estimate the maximum demand of the installation, is the nominal current (In) of the circuit protective device. SwitchedOn Issue 19 - Winter 2010
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ESC REACHES OUT SAFETY MESSAGES TO SWITCHED ON KIDS Working in partnership with the Safety Centre, Milton Keynes, the Electrical Safety Council funded and supported 100 talks to primary level schools in the Hertfordshire, Bedfordshire and Buckinghamshire areas. The main objective of the talks was to educate children on how to keep themselves safe around electricity by raising their awareness of the hazards that electricity can pose, so that they can recognise the dangers, are able to assess the risks and take action to reduce harm to themselves as they go about their everyday lives. The talks were specifically designed to complement the National Curriculum at Key Stages 2 and 3 and were offered to pupils in years 3 and 6 to run in conjunction with the relevant key stage level education. The primary safety messages provided within the talks focused on providing guidance in relation to safety in the home and covered a number of important safety aspects (see below right).
The talks were delivered, using presentation slides and other visual aids; including plug-in RCDs and 4-way bar adaptors. The children were also shown examples of burnt out coiled extension leads and other damaged appliances to emphasise what can happen when things go wrong. Pupils were given copies of the Electrical Safety Council’s Education Fun Pack in addition to posters and work sheets covering the related safety messages and were made aware of the website dedicated to teachers, parents and children. To visit the website go to: www.switchedonkids.org.uk Feedback on the talks from schools has been positive and evaluation of the initiative indicated that the talks have been well received, including interest to participate again should the opportunity arise. A school in Luton said: “This session supported the work in PSHE on safety” and another in High Wycombe said: “It has made the children aware of many potential dangers. The follow up material is very useful and will help the children to remember the messages given during the talk”. to overload sockets by plugging too many electrical • Never appliances into one socket when using an adaptor plug to put drinks on, or have any liquid near to, • Never electrical appliances or equipment. This could cause a fire if the liquid spills onto the equipment to try to get toast out of the toaster whilst the • Never toaster is still plugged in to take electrical appliances, such as plug-in radios • Not and hair dryers, into the bathroom, as it is very dangerous and could cause electrocution turn off electronic games and equipment when • Totheyalways are not in use or when you go to bed dry your hands before you • Tousealways any electrical equipment or you could get an electric shock
If you would like to receive copies of the Electrical Safety Council’s Educational Fun Pack, email schools@esc.org.uk
BACK ISSUES OF SWITCHED ON
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All the previous issues of Switched On are available to read or download from the ‘Business & Community’ section of our website.