Switched On Issue 20 by Electrical Safety First

www.esc.org.uk

Get ready for smart meters

Issue 20 | Spring 2011 | ÂŁ5.00

WELCOME

was delighted to see so many positive comments from organisations that have received grants from the Council to support vulnerable groups in their communities (pages 14-15). The team at the ESC has worked hard over recent months to ensure that direct support goes to those that most need it, and with partners across the UK the ESC’s grant activity is making a real impact on people’s lives. It is even more pleasing to see that the ESC as a UK-wide charity is now also active in Northern Ireland for the first time with its grant programme supporting two local projects.

I recently visited Northern Ireland to meet with the Northern Ireland Electrical Standards Lobbying Group (NIESLG). The main objective of the NIESLG is to introduce a competent persons’ scheme for electrical contractors through the introduction of appropriate regulation. Currently Northern Ireland is the only part of the UK that does not have such a scheme. The ESC is supportive of a competent persons’ scheme being developed, as it should contribute to protecting consumers from unsafe electrical installation work. On the subject of competent persons’ schemes, by the time you receive this edition of Switched On, we will have held the roundtable event to consider the future of Part P. This ESC-led initiative has been welcomed by Andrew Stunnell MP, Parliamentary Under Secretary of State for the Department for Communities and Local Government. We will be speaking with his officials to

discuss how the ESC and its industry partners can develop recommendations on how Part P can be improved both to safeguard consumers and to simplify its implementation and enforcement. Acknowledging the tough financial climate that exists in the UK, we have decided to keep our budgeted activity at the same level. However, we do intend to do more in terms of raising awareness and this will be achieved through increasing our capacity through the provision of appropriate tools such as our new website, details of which can be found on page 6. I am immensely proud of the work that the team puts in to ensure that we can achieve maximum impact with our campaigning messages and I am confident that you will agree that the new website is an excellent tool to help us communicate with consumers and our partners alike.

It is no secret that for an organisation to succeed you have to have good people. With the support of the Trustees we have developed an appropriate Learning and Development strategy to help our staff develop and enhance their skills, both for the benefit of the organisation and themselves. With our approach to learning and with the support of the Trustees and staff we were able to retain our Investors in People (IiP) accreditation when we were reassessed at the end of 2010. Retaining IiP provides us with a strong platform on which we can build our campaigning and technical activities, which should enable us to provide even more direct benefit in the coming years. As always, we would welcome feedback on Switched On, to help us improve the content. Email feedback@esc.org.uk Phil Buckle Director General

ESC Essential Guide now available FOR JUST £35 A year’s subscription to the ESC’s online Essential Guide to the Wiring Regulations is now available for a limited period at the bargain price of just £35 (plus VAT)! Well respected in the industry as a source of authoritative technical information concerning the application of the requirements of the Wiring Regulations (BS 7671), this fully searchable online resource contains over 300 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. Each topic can be printed out for ease of reference as required. During the subscription year, the topics will be updated as necessary to take account of the changes that will be introduced by Amendment 1 to BS 7671: 2008.

To subscribe or for a 7 day free trial, visit www.eschub.org.uk

Working in partnership to support vunerable groups - see page 14 - 15

issue 20 Spring 2011

switchedon your insight into the electrical safety industry

news

technical

features

2 4 5

Welcome

Electric vehicles – making the right connection

10 Towards a smarter Britain

Plug into Safety campaign – working with industry partners Also, Christmas wouldn’t be Christmas without fairy lights but …

Have you ever been asked... when is it really necessary to use insulated hand tools

6 7

Letters

Incorrect use of thermosetting insulated cables at 90 °C current ratings

ESC hosts Part P round-table Also, Towards a safer future: Council finalises five-year corporate strategy

Private rented housing in Scotland: The UK’s leading lights

News in brief

ESC supports search for the UK’s top electrician Also, BEAMA’S Dave Dossett retires after 50 years in industry

14 Working in partnership to support vunerable groups

15 ESC collaborates with leading

property organisations to produce new guidance

SwitchedOn Issue 20 Spring 2011

12 Smart meters: ESC makes Cover image courtesy of Energy UK

functional design recommendations

13 The smart meter installation programme – the electrical safety debate continues

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

news IN BRIEF BEAMA RCD handbook updated

Peter Smeeth, spokesperson for the ACI said: “This is a very worrying discovery and a dangerous practice. We would reiterate that all Atlas Kablo cable in the supply chain should not be sold or installed and should be returned to the place of purchase. “Distributors along with everyone in the electrical supply chain have a duty of care and must comply with their legal duties. We would advise anyone who believes they have recently purchased any suspect cable to get in touch with the ACI,” continued Mr Smeeth.

The RCD Handbook – BEAMA Guide to the Selection and Application of Residual Current Devices – 2010 has been revised to align it with the 17th Edition of the IET Wiring Regulations (BS 7671:2008).

Here’s the ESC’s three top tips for reducing the risk of an electrical fire in your home:

•

Key changes include:

• • •

The inclusion of products introduced since the 2003 edition such as Fused Connection Units Incorporating a Residual Current Device (FCURCD);

You can download if for free at www.beama.org.uk

Faulty cable destroyed as ACI tightens its grip Following the destruction of more than five million metres of faulty electrical cable, the Approved Cables Initiative (ACI) is calling on electrical distributors to consider their responsibilities and not to compound the problem. Atlas Kablo cable, identified as underspecified and therefore unsafe, was the subject of a manufacturer’s product recall last summer. The destruction and recycling of the cable continues, witnessed and verified by BASEC, with many more million metres awaiting action. Yet despite this the ACI understands that some distributors have decided to ignore the product recall and continue to sell some of these cables.

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Explanations of new terms introduced in the 17th Edition, such as ‘Protective Earthing’ and ‘Protective Equipotential Bonding’; Revisions and improvements to aid the selection of the correct RCD and to find faults in RCD Protected Installations.

Housekeeping guru Aggie MacKenzie agrees: “Allowing food and fat deposits to build up on cookers – or trailing leads across them and using the tops of microwaves as extra storage and forgetting to remove things like tea towels draped over them, can all pose a safety risk. So clean up your act - or you could end up burning a lot more than your toast!”

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Keep electrical appliances , particularly kitchen items such as cookers and microwaves, clean and free from grease. If an electrical appliance works erratically, has a flex or cable showing visible wear and tear, or you can smell burning when the appliance is in use, stop using it immediately. Avoid placing anything flammable too close to electric heaters, cookers or fires.

For more information, go to www.esc.org.uk The destruction of faulty electrical cables, (image supplied courtesy of BASEC). For further information about the ACI campaign visit www.aci.org.uk

Grubby home habits help spark thousands of electrical fires Dirty and chaotic kitchens are not just a health hazard – they can also be a fire risk. Almost 13,000 fires each year arise from the misuse of, and faults with, electrical cooking appliances. “In our opinion – which is shared by the fire and rescue professionals we consulted - a considerable number of kitchen fires occur through a casual attitude to cleaning and safety in kitchens,” explains Martyn Allen, head of technical development at the ESC. “And our research also indicates that over a quarter of Britons suspect at least one of their electrical appliances is faulty.”

Mother and son electrocuted in bath A mother and her three-year-old son have tragically died when a heater fell into their bath. It appears that a portable heater may have been knocked into the bath from an adjacent unit. Romanian-born Vasilica Arsene, 37, pulled the heater from the bath and dragged wife Liliana, 34, and son Filip from the water. Filip, was pronounced dead at the scene and Liliana died early the following morning in hospital near their home in Harold Hill, Romford, Essex. A Scotland Yard spokesman told the Evening Standard: “We were called at about 8.30pm. Officers attended with the fire and ambulance service and found a woman and a child who had suffered a cardiac arrest following an apparent electrocution.”

SwitchedOn Issue 20 Spring 2011

news PLUG INTO SAFETY CAMPAIGN – WORKING WITH INDUSTRY PARTNERS he ESC’s Plug into Safety campaign – which aims to reduce electrical fires and accidents by encouraging the installation and use of RCDs - continues to gain momentum. Since the launch of the campaign in May last year, a wide range of wholesale and retail partners, as well as individual contractors, have joined the Council in promoting the message ‘An RCD can save your life’.

esc.org.uk

Regular readers will know that the ESC has produced a variety of material to support the campaign. For example, to help electricians lead the way in encouraging householders to install RCDs, the Council

has produced a tailored ‘electrician’s toolkit’. These are packs containing 50 ESC leaflets that explain both the importance of RCD protection to consumers and the different options available. Detachable blank business cards have also been included, which the contractor can complete and leave with a client after a house-call. To date, over 1.5million leaflets and 19,000 packs have been distributed.

“I always advise my customers to get RCD protection but sometimes it can be difficult to convince people just how crucial it really is” explains Gary Fisher, a London-based electrician. “The Plug into Safety toolkit clearly explains the issues and helps ensure that customers feel well-informed. As the information is from a respected charity and not a commercial enterprise, it also helps demonstrate that I have my customers’ best interests at heart, rather than me wanting to rake in the cash! And, as I can leave information behind for the customer to read at their leisure, I don’t have to do a ‘hard sell’ there and then.”

The toolkits are free of charge and can be obtained from the ESC’s wholesale partners. For your nearest stockist, log onto www.esc.org.uk/plugintosafety. If you prefer to communicate with customers by email, there is also a downloadable PDF of the toolkit available on the website. In addition to providing packs for individual contractors, RCD messages are being communicated via the Council’s retail partners through information leaflets, posters and shelf wobblers, instore. Targeted at high-risk groups, this material aims to remind consumers about the importance of RCD protection, particularly when carrying out higher risk activities such as gardening or DIY. “To ensure the success of the Plug into Safety campaign”, it is vital that we have the support of all sectors of the industry,” explains Lorraine Carney, head of campaigns at the ESC. “So we would like to extend our thanks to all those who have joined us in promoting the campaign”.

CHRISTMAS WOULDN’T BE CHRISTMAS WITHOUT FAIRY LIGHTS BUT … hristmas lights are a long-standing tradition of the festive season. However, old electrical decorations kept in damp and dusty storage spaces can create fire hazards.

As part of the Plug into Safety RCD campaign, the Council launched the ESC’s Safe Stockings Programme which issued advice about the importance of using RCDs and handy tips for a safely lit Christmas. Safe Stockings was timed to take advantage of the season when decorative lighting is often used extensively outside and when many presents are of the electrical variety. The UK’s electrical industry has a strong safety record, yet every year in the UK, about 70 people die and 1.2 million are injured in

SwitchedOn Issue 20 Spring 2011

electrical accidents in the home. There are also more than 20 000 domestic fires each year that occur through misuse of, or fault with, electrical appliances or installations. The Council urged shoppers to put their family’s safety above the glitz and excitement of the festive season by checking their home for RCD protection, noting that plug-in RCDs costing just £10 were a cost-effective and simple way of ensuring a safe and happy Christmas without breaking the bank. Extensive coverage was gained in national press and radio, including AOL, MSN and Sky News radio. Regional press coverage was also strong with particular focus in areas of low RCD uptake in England.

letters Keep up the good work I always have a quick flick through your magazine, but the last issue was the best by far. The article on green goo was great. I knew it was caused by deterioration in the cable and that it was important not to disturb it as it can be brittle with decreased insulation, but your article has now given me a complete understanding of the problem.

The article “Have you ever been asked…?” on RCD tripping was

also an excellent choice. This happens on almost a daily basis and I am often asked by worried customers what has happened: “All the electrics have gone.” I have asked any number of other electricians why this is and nobody has had a real explanation. The usual answer is just: “Yeah, that happens to me. It’s because the RCDs are so sensitive that they pick up anything.”

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 the Editor of Switched On at: 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.

I always told customers that it’s just a parallel path on the earth. I am so pleased to have a real understanding of what is really happening, it gives me a technical explanation in my armoury next time I’m asked and has helped solve one of those unsolved mysteries that sometimes make you question yourself – thank you.

easy to understand and real, everyday issues, well done. They have transformed your magazine from one that used to warrant a quick flick through to check for anything interesting that had articles more suited to homeowners into a informative and relevant journal that I don’t want to miss. Well done and thank you.

Enemy at the gates

Keep the technical articles coming, they are clear, concise,

Philip Messenger Via email

Dave Russell DPR Electrical Services

Further to the letter from William Budd on electric gates (Issue 19 of Switched On), there is a requirement to have force limit sensors and equipment on gates, now with retest and certification issued.

It’s electrifying... It’s the same address with a fresher, more contemporary look. Visit www.esc.org.uk for improved guidance and advice.

• • • •

It’s interactive Easier to browse Written in plain English Get information about our latest campaigns to keep consumers safe

Whether you are a mum, businessman, government organisation or electrician you will find updated tailored information to meet your electrical safety needs.

Experience the vibrancy and richness of the Electrical Safety Council’s new website. 6

SwitchedOn Issue 20 Spring 2011

news ESC SUPPORTS SEARCH FOR THE UK’S TOP ELECTRICIAN alling all apprentices – the 2011 SkillELECTRIC competition is looking for the industry’s most promising talent to be named the UK’s best electrician.

SummitSkills. “Past competitors have gone on to become an even greater asset to their employers and a inspirational role model for their peers.”

The closing date to register for the competition is 24 March 2011. Call 01908 303972 for more information or visit www.skillelectric.org.uk

During the competition, organised by SummitSkills and supported by the ESC, entrants will be assessed on a series of challenging practical tests reflecting their day-to-day work. Regional heats will be held around the country, culminating in a grand final in September. This year will see SkillELECTRIC finalists competing side-by-side with those from SkillPLUMB, SkillPIPE and SkillFRIDGE at a prestigious event that will also feature the UK final of construction competition SkillBUILD. “Taking part in SkillELECTRIC is not only highly motivational for employees but also drives them to achieve higher standards back in the workplace,” said Neil Collishaw, head of skills competitions and awards at

Calling all apprentices – Register now for the 2011 SkillELECTRIC competition - www.skillelectric.org.uk

BEAMA’S DAVE DOSSETT RETIRES AFTER 50 YEARS IN INDUSTRY

Dave Dossett has been a life-long ‘Hammers’ supporter.

To honour his many achievements, BEAMA organised a surprise reception attended by colleagues, industry figures and his family at West Ham United’s Upton Park ground –

A surprised Dave Dossett received several gifts to mark the occasion, including a West Ham ‘Dossett’ shirt signed by the team. He said: “I’m proud to have been part of BEAMA’s evolution into the successful, lean and influential organisation it is today.

fter nearly 50 years in the industry and 20 years with BEAMA, latterly as its executive chairman, popular electrotechnical sector figure Dave Dossett has retired.

“It’s been a privilege and pleasure working in this industry and I thank the many colleagues and friends I have made for their friendship and support. It’s a great industry with excellent people - it’s been fun.” Until the end of 2012, Dave Dossett will continue on a part time basis as president of Cenelec, the European Committee for Electrotechnical Standardisation, and as advisor to the BEAMA Board and its CEO, its new team in Installation, and on standards and industry issues. Also, he will complete his term as immediate past chairman of the Electrical Safety Council. Terry Rowbury, BEAMA’s energy sector director now has the additional role of installation sector director and Keith Smith has taken over as secretary of the AntiCounterfeiting Working Group, upon which Dave Dossett served for the past 10 years.

SwitchedOn Issue 20 Spring 2011

news ESC HOSTS PART P ROUND-TABLE ast December, the government announced plans for reviewing the Building Regulations for England and Wales.

In a statement, Communities Minister Andrew Stunnell set out the main elements of the programme of work that the Department for Communities and Local Government (DCLG) will lead this year to establish the changes required to the Building Regulations regime between now and 2013 to ensure that it remains fit for purpose and delivers its contribution to the government’s policy goals. The programme was developed following consultation earlier last year between DCLG and a wide range of stakeholders, including the ESC. A key theme to emerge from the consultation was that although the Building Regulations regime was generally considered to be fit for purpose, there are things that can be improved. The consultation process reportedly confirmed the DCLG’s belief that the Building Regulations should remain the

TOWARDS A SAFER FUTURE: COUNCIL FINALISES FIVE-YEAR CORPORATE STRATEGY

national minimum standard that building work should comply with. However, the process also identified a number of areas where DCLG thinks there may be potential for deregulation and streamlining of the technical and procedural aspects of the regulations. In particular, the government proposes to evaluate the contribution that Part P (Electrical safety – dwellings) has made to improving electrical safety in and around homes since the requirements were introduced in 2005. The evaluation will include a review of the requirements, their implementation and the associated compliance mechanisms to enable DCLG to determine whether there is any case for change. To assist this evaluation process, the ESC hosted a round-table event in March that brought together a range of parties having a particular interest in Part P and its future application. The aim was to examine how best to create a strong evidence base to enable the impact of Part P to date to be assessed, and to consider what industry

he Electrical Safety Council has now finalised its five-year corporate strategy covering 2011-2016.

The strategy sets out the key objectives for the next five years which are linked to the charity’s vision for everyone to be safe from the dangers that electricity can create. In line with its core focus on electrical safety, the Electrical Safety Council identifies its strategic priorities as follows: 1. Building the capacity of its people while creating a positive working environment; 2. Safer products Working with key stakeholders to influence consumer behaviour so that they buy safer products and help tackle the evergrowing issue of counterfeit products.

could do to develop consensus during 2011on a preferred way forward. Parties represented at the round-table event, which was chaired by Ann Robinson of uSwitch, included: ABE (Association of Building Engineers) Competent Persons Forum DCLG ELECSA ECA (Electrical Contractors’ Association) IET (Institution of Engineering and Technology) LABC (Local Authority Building Control) NAPIT NICEIC TSI (Trading Standards Institute) Which? The outcomes of the event will be used to inform and support responses to a further DCLG consultation on the future of Part P, which is expected at the end of this year. The ESC understands that, following consideration of the consultation responses and further refinement of the proposals, DCLG’s aim would be for any necessary amending legislation and revised guidance in Approved Document P to be published in October 2012, six months prior to any new provisions coming into force in April 2013.

The Charity will also seek to influence consumers to change their behaviour to avoid the misuse of electrical products; 3. Housing standards The Charity intends to influence landlords and homeowners to upgrade electrical installations in older properties to current standards including the installation and use of residual current devices (RCDs). The Charity will influence landlords and homeowners to carry out regular checks of the condition of their electrical installations and electrical appliances. The Charity will also monitor the application, review and development of Building Regulations in the British Isles to represent the electrical safety interests of consumers; 4. Research Maintaining a robust evidence base to support its work and will ensure SwitchedOn Issue 20 Spring 2011

news PRIVATE RENTED HOUSING IN SCOTLAND: THE UK’S LEADING LIGHTS he Public Affairs work of the Electrical Safety Council seeks to influence the political landscape across the United Kingdom. The Scottish Parliament has power over housing rules in Scotland, and the Council has therefore been engaging with MSPs to discuss electrical safety standards in Scottish homes.

This is a key time to influence MSPs in the run up to the Scottish Parliament elections in May. It seems likely that the SNP and Scottish Labour Party will be the two main parties in Scotland after the elections, and the Council has key supporters in both. However, between now and the elections, the Private Rented Housing Bill is making its way through the chamber. There is support from across the Parliament to increase standards in private rented accommodation, and it is likely that the Bill will pass before the election. The Electrical Safety Council has submitted evidence to the Bill Committee, stressing the need for improved assessment of electrical safety in privately rented housing. The Council is calling for two key action points. Firstly, there should be mandatory Periodic Inspection Reports (PIRs) every five years in all private rented properties in

this evidence is current. In addition, the Electrical Safety Council will commission independent research and impact evaluation to further the objective of public safety; 5. Profile In positioning itself as a charity pursuing public safety, the Electrical Safety Council will strengthen and promote the brand with the public through effective partnerships with key stakeholders; 6. The green economy The Charity will help ensure that technological advances in integrating renewable sources into the UK electrical supply system and emergence of other carbon-saving technologies do not compromise the safety of people and places. The Charity will also continue to work with key

SwitchedOn Issue 20 Spring 2011

Scotland. The Bill as introduced calls for the introduction of a Tenant Information Pack listing various key details of the property, and the ESC believes a PIR should make up a key element of this. Currently, the duty of the landlord to carry out repairs and maintenance on properties is only enforceable if the tenant informs the landlord of faults, or if the landlord is made aware in some other way. Given the low level of knowledge of tenants, and the often ‘invisible’ nature of electrical risks, the Council believes a reactive regime is insufficient protection; tenants may not be in a position to recognise and notify the landlord that there is a problem until it is too late. In addition to this, the Council is calling for a clear statement in the Tenant Information Pack on whether or not RCD protection is installed. The ESC believes explanatory information tied to the Repairing Standard should also be provided on good electrical safety. Landlords in Scotland will therefore need to actively consider the issue of RCDprotection, and this should over time deliver a shift in landlords’ thinking and approach to electrical safety, as well as increase tenants’ awareness and encourage them to ask landlords about the absence of an RCD.

If the Scottish Parliament enacts these changes, it will ensure that the nation’s safety standards in private rented housing are higher than those in any other part of the UK. Where Scotland leads the way, other nations within the UK can follow. This year, the Welsh Assembly is also likely to have housing powers devolved, and the ESC intends to use similar techniques to achieve regulatory change there.

stakeholder groups associated with the smart meter programme to help ensure the safety of consumers and meter installers; and 7. Income streams The Charity will continue to exercise financial prudence while seeking to diversify its income streams. Phil Buckle, director general of the Council, notes that: “A rolling three-year business plan will be developed to ensure that a focus remains on the priorities set out in the strategy document, including appropriate and specific measures to ensure key objectives are monitored.” He adds that the Charity will continue to strive to ensure consistent positive outcomes for its beneficiaries over the life of the strategy and beyond.

Towards a smarter The government has announced plans to install smart electricity meters in all of the UK’s 26 million homes and two million plus smaller nondomestic premises by 2020. This, together with other technological changes, will have a big impact upon electrical installations. Rather than viewing the introduction of smart meters as an end in itself it should be seen as the first step along a pathway that will lead to radical changes in the way electricity is generated, distributed and used. Before looking at these changes we first need to consider the forces that are causing these changes to take place.

meters “alsoSmart need to be able to monitor energy flowing from and to the grid

”

The first decade of the 21st century saw a somewhat reluctant world-wide acceptance that global warming

presented mankind with challenges of immense proportion. Governments throughout the world now accept that that the growth of CO2 (carbon dioxide) in the atmosphere is a factor influencing global warming and that it is vital that they act to reduce CO2 emissions to the atmosphere. In 2009 the British Government produced the Low Carbon Transition Plan which aims to reduce the UK’s CO2 emissions by 80% of the 1990 levels, by 2050. Also included was an interim target of a 34% reduction by 2020. These targets will require a radical review of how we use all forms of energy and it is expected that the steps taken to achieve these targets will have a significant impact upon industry, the built environment and transport systems.

A smart meter will: 3

1 measure electricity and gas consumption giving consumers 5

and supply company real-time energy useage data.

2 make estimated bills unnecessary. 3 allow people to monitor the power they have generated using microgeneration units such as wind turbines and solar panels.

4 1

2 4

enable consumers to use off-peak tariffs when charging items such as electric cars.

A smart meter could: HANDLE WITH CARE

1 2

allow customers to interact with appliances via the home area network.

enable consumers to monitor their energy usage through internet access via computer, mobile phone or TV.

measure surplus electricity being sold back to the electricity supplier.

GAS FLOW

IF YOU THINK YOU SMELL GAS

1 3 1 3 1

1 Turn off the supply at the control valve. Open doors and windows. Do NOT use naked flames. Do NOT turn electrical switches on or off. Do NOT smoke. IMMEDIATLEY CONTACT GAS EMERGENCY SERVICE

0800 000 000

For use with gases consisting mainly of Methane excluding LPG Q max 6m2/hr Q min 0.04m2/hr P max 75 mbar

Press button A until Metre Index is visible thenpress Button B to update Index

Under the gas Act this meter is the property of the Gas Supplier to these premises

ACCESS ONLY BY AUTHORISED PERSONNEL

1 2

4 4 5

alert consumers that equipment is in standby mode. automatically inform electricity suppliers about a power cut or a problem with the grid system enabling swift repair.

Figure 1: Examples of smart devices connected to home area network

SwitchedOn Issue 20 Spring 2011

PHASE 1

Scoping study (Prospectus)

KEY DECISON POINT Decisions to be taken by ministers and GEMA

EARLY 2011

PHASE 2 Detailed design

GO ACTIVE Supplier rollout obligations

SPRING 2012

PHASE 3

Implement design

DCC providing services

AUTUMN 2013 Image courtesy of Energy UK

GO LIVE

PHASE 4 Installation

r Britain To meet the CO2 reduction targets, by 2050 we will need to generate virtually all electricity using clean sources of energy. It is expected that by 2050 the systems for generation, transmission, distribution and utilisation of electrical energy will be very different from those of today and are likely to consist of number of clean generating stations supplemented by a vast array of renewable energy sources feeding electrical energy into the distribution system. To optimise performance and minimise environmental impact the electrical generation and distribution system of tomorrow will require the integration of sophisticated information and communication technologies and the term ‘Smart Grid’ has been coined to describe such electrical power systems. An important component of the smart grid is the smart meter which is an energy meter with the ability to communicate with both the customer and the supplier. Smart meters also need to be able to monitor energy flowing from and to the grid. The installation of smart meters is expected to transform how energy is used in domestic premises. In the longer term, the smart meter will form the hub of a ‘Home Area Network’ which will use wireless technology to enable two-way communication between the hub and smart devices controlling items such as home heating systems, micro-generation devices, electric vehicle charging and home laundries. The introduction of smart meters is likely to lead to the introduction of a new range of tariffs designed to encourage the consumer to use energy when the demand is low. Using the smart meter, the consumer will be able to select options that ensure items of equipment that draw large amounts of energy are only connected when cheaper tariffs are available. The

SwitchedOn Issue 20 Spring 2011

COMPLETION 2020 Figure 2: Timetable for installing smart meters

consumer will interact with the smart meters (gas and electricity) using an ‘In Home Display’ which will enable them to monitor their energy use. The smart meter will also communicate details of energy usage to the supplier and this information will, in the longer term, be used to control the smart grids. The Department of Energy and Climate Change (DECC) has, since last July, been liaising with interested parties to produce a co-ordinated approach to the smart meter rollout. As shown in figure 2 we are approaching the end of phase one when the Office of Gas and Electricity Markets (Ofgem) is scheduled to publish the results of its public consultation. These outcomes will shape how the installation programme is to be implemented. The installation of 28 million smart electricity meters by 2020 presents both enormous challenges and a unique opportunity to monitor the condition of existing electrical installations. It also serves to provide an opportunity to distribute safety information on gas and electricity services to all UK households. Throughout phase one of the timetable the Electrical Safety Council has been actively involved in promoting issues that impact upon the electrical safety of consumers and meter installers. In the winter 2010 issue of Switched On, we reported on some of the Council’s activities in relation to the smart meter programme, in particular the round-table event that the Council hosted in October 2010. At the time of writing, the ESC and others who participated in the consultation process were still waiting for the conclusions of the smart meter prospectus to be published. On receipt, a follow up article will brief readers upon the proposals and the Council’s next steps.

installation “ofThe 28 million

“

smart electricity meters by 2020 presents both enormous challenges and a unique opportunity

”

Smart meters: ESC makes functional design recommendations In November last year, shortly following the ESC’s Smart Meter round-table event reported in the previous issue of Switched On, the Council wrote to Ofgem making recommendations concerning the functional design requirements for smart electricity meters. The ESC strongly recommends that a manual isolating switch is incorporated in all smart electricity meters to provide a safe and convenient means for non-electrical industry parties, such as electricians, to isolate the supply to domestic premises when necessary for safe working on consumers’ installations (for example to replace consumer units). This facility would avoid the need for them to arrange for the supplier or meter operator to remove the cut-out fuse, as is the current unsatisfactory situation. The provision of such a means of isolation would also be of considerable benefit to consumers in terms of cost and convenience when having electrical work carried out. The ESC pointed out that the provision of an integral isolating switch would also help address another safety issue that the Council had previously drawn to Ofgem’s attention – the risk that meter tail connections at the main switch in consumer units may be loosened when meters are replaced, possibly introducing a fire hazard. The Council believes that the meter installer should be responsible for checking the tightness of these connections before re-energising an installation and leaving site. However, there is clearly reluctance on the part of some meter operators to do this, and so the party to be made responsible for this safety check has yet to be determined. If responsibility for checking the tightness of these connections following the installation of a new meter is to be left with the occupier or landlord (a situation that would be of concern to the ESC), they would need to be advised to call in a registered electrician to check the connections on their behalf. However, for safe working, this would also require the meter operator to be called back to remove the cut-out fuse – a potentially expensive and unpopular exercise for the consumer, especially if the connections were found to be tight. But at least the repeat involvement of the meter operator could be avoided if a means of isolation had been incorporated in the meter.

In conjunction with an integral means of isolation, the Council also recommended to Ofgem that the functional design requirements permit the outgoing (load side) terminals of the smart meter to be accessed by electricians, that is, not sealed. This would enable the consumer’s meter tails to be replaced (for example when a consumer unit is relocated) without needing to call in the meter operator to remove the cut-out fuse and to connect the meter tails to the meter. The ESC pointed out that another benefit of providing an isolating switch in the meter is that it would avoid the need to install separate isolating switches between meters and consumer units, as is the practice in some parts of the UK, to overcome the ‘access to service fuses’ issue. The provision of such separate switches not only usually incurs additional costs for consumers, but also introduces additional connections in the meter tails that are potential weak points in the integrity of supply arrangements. In response to these recommendations, Ofgem called for qualitative and quantitative evidence to support the case for changing the smart meter specification which, with the support of the electrical trade associations and contractor registration bodies, was quickly provided. Based on Part P notification statistics, it was estimated that, every year, electrical contractors carry out almost 400,000 jobs in domestic premises in England and Wales alone that necessitate the temporary disconnection of the incoming supply to provide for safe working. Further evidence was provided by local authorities in Scotland regarding the very substantial cost to them of having separate isolating switches installed between meters and consumer units. To help complete the picture for cost/benefit analysis purposes, the Council asked Ofgem to call for similar quantitative and qualitative information from the electricity suppliers/meter operators, that is, how many visits do they make to domestic premises each year to remove and replace service fuses for the purpose of temporary isolation, and how many isolators do they fit each year for the same purpose. At the time this article was written, the Council was still awaiting the outcome its recommendations and the statistics from the electricity suppliers/meter operators. SwitchedOn Issue 20 Spring 2011

The smart meter installation programme – the electrical safety debate continues A year ago, in the spring 2010 issue of Switched On, we asked whether the once-in-a-lifetime opportunity that will be provided by the smart meter installation programme to check the condition of the electrical intake arrangements in all 26 million homes over a relatively short period of time would be missed. Since then, the Council has become increasingly reassured that steps are being taken by the electricity supply industry to address many of the so-called ‘legacy safety issues’ that will be found during the meter replacement programme, such as old service heads in a dangerous condition. However, the ESC is still working with the supply industry on some other safety issues, including: Reporting on the apparent condition of consumers’ electrical equipment The Council has proposed to the MOCOPA* Health and Safety Working Group that meter installers should complete and leave, for the benefit of the occupier or landlord, a short report on the (mainly visual) condition of the parts of the electrical intake equipment for which the consumer is responsible. We have tabled for consideration a draft inspection report form to record urgent safety concerns such as:

• • • • • •

Your electrical equipment is damaged, exposing live parts to touch Your electrical installation appears not to be adequately earthed Your consumer unit is showing signs of overheating The cables connecting the meter to your consumer unit are in a poor/damaged condition Your installation appears not to be adequately main bonded Your electrical installation is protected by an old voltageoperated earth-leakage circuit-breaker (which may not have been tested for years).

And potentially less urgent concerns such as:

• •

The connections at the point the cables from the meter enter your consumer unit may have been loosened during the meter replacement process The cables connecting the meter to your consumer unit, and/or the earthing conductor for your installation, appear to be undersized

SwitchedOn Issue 20 Spring 2011

• •

You have a very old arrangement of separate main switches Combustible materials are being stored close to your electricity supply equipment.

At the time of writing this article, the scope of the condition report was still under debate, particularly the proposals to comment, if appropriate, on the adequacy of the earthing arrangement, and to check the tightness of the meter tail connections at the consumer unit main switch (neither of which meter operators were previously intending to do). Should any of these concerns be identified by the meter installer, the intention is that the occupier or landlord would be recommended to seek advice from a registered electrician with the proviso that, while the meter installer may have observed potential defects, damage or deterioration which may present electrical safety hazards, such a (mainly visual) inspection alone cannot fully determine whether an installation is safe for continued use. Warning label The ESC is supporting a proposal from the Fire and Rescue Service, based on its incident reports, for meter installers, where appropriate, to fix a label on or adjacent to the electrical intake equipment to warn householders not to store combustible materials close to that equipment. The proposal follows a number of serious fires in homes where the effects of an electrical fault, which would otherwise have been contained within the intake equipment, have set light to adjacent stored materials. Such a warning is particularly appropriate where the electrical equipment is located adjacent to an escape route, for example under the stairs.

A preliminary draft of the proposed warning label

The proposed label will also warn against storing any items near the intake equipment that may cause damage by impact (such as a bike). We will report further on these and other related issues in future issues of Switched On. *The Meter Operation Code of Practice is an agreement between electricity distribution businesses and electricity meter operators in Great Britain

news WORKING IN PARTNERSHIP TO SUPPORT VUNERABLE GROUPS he Electrical Safety Council (ESC) is now working in partnership with 47 consumer safety organisations UK-wide to support vulnerable groups and help safeguard their health and safety. ESC’s two key funding initiatives – the Home Improvement Grants Scheme and Fire Safety Fund – aim to improve electrical safety and awareness in the

As indicated in the map, 24 of these projects are funded through the Home Improvement Grants Scheme. This initiative allows the ESC to work in collaboration with home improvement agencies across the UK to provide a much needed source of funding to carry out urgent essential electrical work. Grants are awarded to individuals who are householders over 60 years of age, on means-tested benefit or state pension (and with no other income). Partnership agencies are responsible for finding the beneficiaries, identifying and organising the electrical work – which needs to be undertaken by a registered contractor - and for ensuring it is completed to required safety standards.

16 15

Inverness Aberdeen 17

One of the award holders is housing charity Shelter’s Gable project, which is based in Northern Ireland (NI). Gable assists elderly and disabled homeowners with home improvements and repairs, and is the first NI project to be awarded funding under this scheme. The award will support the organisation’s existing home improvement scheme and allow Gable to fund additional work not covered by existing funding streams. This can range from undertaking periodic inspection reports to upgrading earthing, bonding and consumer units.

22 2 15 10

14 17

Edinburgh

Glasgow 3 22

6 18

Belfast Newcastle 11 12

Blackpool

home. Both schemes have distributed a combined fund total of £182,000, which has been shared between 26 projects in England, 11 in Scotland, 7 in Wales and 3 in Northern Ireland. The map lists these partners and illustrates the geographical spread of funded projects across the UK.

“The funding we have received from the ESC is particularly important to us in the light of a recent and significant reduction in the housing grant budget for Northern Ireland,” says Stella LePoidevin, grant manager at Gable. “We look forward to delivering these electrical works to our clients and hope that the partnership with the ESC is one that will continue long into the future.”

Leeds 19

8 12 11 7 23

Manchester

Liverpool 10 19

9 18

Birmingham 23

21 20

24 4

Swansea

The ESC has funded two other projects in Northern Ireland via its Fire Safety Fund, which supports projects aimed at reducing deaths and injuries from electrical fires. In total, 23 consumer safety organisations – including five Fire and Rescue Services and six Trading Standards units - were awarded a share of £102,000. One partner, 13 Cambridgeshire Trading Standards (TS), used funding to run an electric blanket testing event and reported a 60% failure rate. Some blankets tested were 20 over 30 years old. 14

4 1

Cardiff

1 Bristol

8 9 3 2

London 5

Plymouth 14

As the ESC recommends disposing of electric blankets that are 10 years old or over, Cambridgeshire TS was able to offer replacement blankets. “During the testing week there was a house fire in the area that

news Home Improvement Grants Scheme

Fire Safety Fund

Organisation 1 Bristol Care & Repair 2 Perthshire Care & Repair 3 Clyde Valley Care & Repair 4 Neath Port Talbot Care & Repair 5 Torfaen Care & Repair 6 Gable (Shelter) 7 FILT (Foundations Independent Living Trust) 8 Greenwich Home Improvement Agency 9 Newham Home Improvement Agency 10 Revivial Home Improvement Agency 11 Traﬀord Care & Repair 12 Middlesbrough Staying Put Agency 13 West Norfolk Care & Repair 14 Inverclyde Care & Repair 15 Clackmannanshire Care & Repair 16 Orkney Care & Repair 17 Aberdeen Care & Repair 18 Age UK Nottingham & Nottinghamshire 19 Rochdale Home Improvement Agency 20 Daventry Care & Repair 21 Mid & West Cornwall Care & Repair 22 Care and Repair South Lanarkshire 23 Care and Repair Powys 24 Care and Repair Carmarthenshire

Organisation Location 1 South Wales Fire & Rescue Service Pontyclum , Wales 2 Barnet Housing London, England 3 Community Safety Div. Wandsworth Council Wandsworth, England 4 Age Concern Sir Gar Llanelli , Wales 5 Act On It East Hoathly, England 6 Oxfordshire Fire & Rescue Service Oxford, England 7 Lancashire Fire & Rescue Service Preston, England 8 Salford City Council Salford, England 9 Bolsover District Council Bolsover, England 10 The Risk Factory Edinburgh, Scotland 11 Darlington Borough Trading Standards Darlington, England 12 Traﬀord Trading Standards Manchester, England 13 Cambridgeshire Trading Standards Cambourne, England 14 Royal Association for Deaf People (RAD) Colchester, England 15 Shetlands Islands Trading Standards Lerwick, Scotland 16 TADA Rural Support Network Portadown, N. Ireland 17 Strathclyde Fire & Rescue Service Glasgow, Scotland 18 Omagh District Council Co Tyrone, N. Ireland 19 Staﬀordshire Fire & Rescue Service Burslem, England 20 Essex County Council Trading Standards Chelmsford, England 21 Northamptonshire Trading Standards Northampton, England 22 Perth & Kinross Community Safety Partnership Perth, Scotland 23 Danger Point Holywell, Wales

Location Bristol, England Perth, Scotland Motherwell, Scotland Neath, Wales Torfaen, Wales Strabane, Northern Ireland Glossop, England London, England London, England Stoke on Trent, England Manchester, England Middlesbrough, England King's Lynn, England Greenock, Scotland Alloa, Scotland Kirkwall, Scotland Aberdeen, Scotland Nottingham, England Rochdale, England Daventry, England Cornwall, England Lanark, Scotland Powys, Wales Carmarthenshire , Wales

was caused by a faulty electric blanket - which clearly justifies the time, money and effort spent delivering the project,” says Hannah Shepherd, trading standards officer at Cambridgeshire TS. “We greatly appreciate the support received from the Electrical Safety Council.”

Carney, head of campaigns at the ESC, helped local councillors from the area select the winner. Nine-year-old Kasia Procter, from Holy Ghost Primary School, designed the winning poster. This will feature in a widespread outdoor poster campaign throughout Wandsworth.

Another funded partner, Wandsworth Council, will use its award to help deliver a range of children’s awareness raising activities and events. The Council has already utilised funding to run a children’s poster competition highlighting the dangers of electricity. Lorraine

Projects will continue to run until the end of March. For further details and information on all of the Council’s Home Improvement Grant Schemes and Fire Safety Fund projects, please visit the website at www.esc.org.uk/business-and-community.

ESC COLLABORATES WITH LEADING PROPERTY ORGANISATIONS TO PRODUCE NEW GUIDANCE he ESC has teamed up with the Association of Residential Managing Agents (ARMA) and several other UK housing associations to produce a new guide about electrical safety in the communal areas of residential properties.

ARMA, Genesis Housing Group, Guinness South, Radian Housing Group and the Retirement Lease Housing Association have all contributed to the production of the guide which aims to raise awareness among landlords of their legal obligations relating to electrical safety in the common parts of residential buildings. Common parts include staircases, hallways, landings and boiler rooms – areas that are not the responsibility of the building’s respective residents. This will largely apply to blocks of flats and Houses in Multiple Occupation (HMOs) in England and Wales. The charity was approached by ARMA after concerns were raised in the wake of several high profile electrical incidents such as the fire at Lakanal House in Camberwell, London. The fire caused the death of six people in July 2009 after a television burst into flames on the ninth floor of the residential building.

SwitchedOn Issue 20 Spring 2011

Both the ESC and ARMA are concerned that many landlords and managing agents are unclear about their responsibilities with regard to electrical safety in the communal areas of their properties - an issue that is largely due to a lack of resources available in the area. A survey of ARMA members supported these concerns and it was revealed that 84% of recipients felt that a guide addressing inspection and testing in communal areas would be extremely helpful. The new guide is presented in a similar booklet style format to the successful Landlord’s Guide to Electrical Safety, which was released early last year. The charity hopes that this new guidance will go some way towards improving the understanding of electrical safety responsibility in communal areas so as to prevent electrical incidents and ensure the safety of residents. The guide is available to download from the ESC website (www.esc.org.uk) as well as in hard copy which can be requested by email (enquiries@esc.org.uk.)

technical

Electric vehicles – making the right connection 18.1.2 Normal operation of BS 1363: Part 2 1995 plus Amendments 1, 2 and 3, and

We investigate the suitability of the UK 13 A plug and socketoutlet system for charging electric vehicles. Standardisation work is being undertaken at European and International level to establish and agree on a harmonised approach for the safety, interoperability and connectivity of an electric vehicle (EV) charging infrastructure. In the meantime, many EV manufacturers are looking at the suitability of existing National domestic plug and socket-outlet systems as a connection solution (potentially as an interim measure) for charging EVs. In UK homes, 13 A socket-outlets conforming to the product standard BS 1363 are generally used for the connection of current-using equipment. One of the main challenges, according to a leading motor vehicle manufacturer, is the amount of energy needed to fully and safely charge EV batteries within a reasonable period of time. A fully discharged EV battery (typically requiring 27 kWh of energy) is likely to take over eight hours to reach full capacity when connected to the electricity supply via a standard UK 13 A plug and socket-outlet. This charge time has recently provoked much discussion within the EV and electrical equipment manufacturing industry regarding the capability of BS 1363 plug and socket-outlets to safely, repeatedly and reliably transfer 27 kWh of energy, and regarding the continuous operation of BS 1363 13 A Socket-outlets at their maximum rated current. Following an increase in the number of queries relating to electric vehicles, particularly to do with the type of plug and socket-outlet for the charging arrangements, the ESC decided to commission an independent laboratory to determine the mechanical and electrical stresses that may occur to BS 1363 socket-outlets when subject to full-load continuous operation. A selection of commercially-available 13 A 250 V, switched two-gang fixed socket-outlets were subject to:

• 16

5000 insertions/withdrawals of an approved BS 1363 rewireable plug at 13 A 250 V to simulate normal wear as per sub-clause

•

3 x 8 hour operational runs at 13 A 250 V

The socket-outlet and plug terminal temperatures and plug accessible surface temperatures were monitored during the test. A visual examination was carried out after the test to identify any excessive wear or harmful effects. For all the samples tested, the maximum temperature rise at terminals and touch surfaces were within the limits specified by the product standard, and a visual examination of all socket-outlets after all testing showed no degradation beyond that expected from normal operation. Although this investigation finds that BS 1363 socket-outlets are capable of continuous operation under the test conditions described above, the small sample size and the limited testing duration and repetition must be taken into account when considering the results. In addition to the laboratory investigations, the ESC formally requested a response from the British Standard Technical Committee responsible for the safety and performance of UK socket-outlets regarding the use a BS 1363 plug and socket-outlets for the application of vehicle charging, and their suitability for 13 A continuous loads. Also, the British Electrotechnical and Allied Manufacturers Association (BEAMA), representing over 300 manufacturing companies in the electrotechnical sector, has declared that BS 1363 plug and socketoutlets manufactured by its members comply fully with their standards and are suitable for 13A continuous loads, within the scope of the standard BS 1363. A copy of the laboratory test report is available to view in the ‘business and community’ section of the Council’s website www.esc.org.uk SwitchedOn Issue 19 - Winter 2010

technical

Have you ever been asked...

when is it really necessary to use insulated hand tools

A question sometimes discussed on electrical installation forums is: when does an electrician really need to use insulated hand tools? Regulation 14 of the Electricity at Work Regulations 1989 (EWR) states that:

No person shall be engaged in any work activity on or so near any live conductor (other than one suitably covered with insulating material so as to prevent danger) that danger may arise unless â&#x20AC;&#x201C; (a) it is unreasonable in all the circumstances for it to be dead; and (b) it is reasonable in all the circumstances for him to be at work on or near it while it is live; and (c) suitable precautions (including where necessary the provision of suitable protective equipment) are taken to prevent injury.

Although the above regulation permits work on or near live conductors, this is only the case where all three conditions (a) and (b) and (c) above are satisfied. Guidance on and about the conditions can be found in the Memorandum of guidance on the Electricity at Work Regulations 1989 (HSR25), downloadable free at www.hse.gov.uk/pubns/books/hsr25.htm. Most types of electrical work should not be carried out on or near live conductors. If danger may otherwise arise, the conductors should be made dead, and proved to be so, before any work on or near them commences. Furthermore, adequate precautions (such as locking off the means of isolation and placing of notices) should be taken to prevent the conductors from becoming electrically charged during the work, if danger may thereby arise (EWR regulation 13 refers).

SwitchedOn Issue 19 - Winter 2010

EWR regulation 14 recognises that there are circumstances where it is unreasonable, having regard to all relevant factors, for the equipment to be dead while work proceeds. Examples of work on electrical installations where regulation 14 often applies include electrical testing to establish whether electrical conductors are live or dead, or to establish whether the polarity of the incoming supply to an installation is correct or incorrect, or to measure the earth fault loop impedance or the prospective fault current at the origin of an installation. Working on or near live conductors should be the exception, not the rule. There is nothing wrong with using insulated hand tools where this is not necessary for safety, such as when working on a circuit known and proven to be dead. But if an electrician finds himself or herself thinking of using an insulated hand tool as a precaution against injury in connection with working on or near a live conductor, he or she should think again. The use of insulated hand tools, like any other precaution intended to prevent injury, cannot alone make it permissible to work on or near live conductors. As already stated, such work is permitted only where all three conditions (a) and (b) and (c) of regulation 14 are satisfied. Where insulated hand tools are to be relied on as protective equipment for the purposes of condition (c), they should meet the requirements of BS EN 60900: 2004 â&#x20AC;&#x201C; Live working. Hand tools for use up to 1000 V a.c. and 1500 V d.c., be free from damage, deterioration or modification that may result in danger, and be suitable for the work concerned. Depending on the circumstances, other protective equipment, including protective clothing, may be required. Further guidance about protective equipment and other precautions can be found in Electricity at work, safe working practices (HSG85), downloadable free at www.hse.gov.uk/pubns/priced/hsg85.pdf. This publication also covers deciding whether to work live or dead.

technical Incorrect use of thermosetting insulated cables at 90 °C current ratings In some cases it is not appropriate to size thermosetting insulated cables on their full 90 °C current ratings. Cables having thermosetting insulation, such as cross-linked polyethylene (XLPE), are capable of being operated with a maximum conductor temperature of 90 °C in normal service. This gives them a higher current-carrying capacity than 70 °C thermoplastic (PVC) insulated cables of similar construction and conductor size. However, conductors intended to operate at a temperature exceeding 70 °C in normal service must not be connected to switchgear, protective devices, accessories or other types of equipment unless the equipment manufacturer has confirmed that the equipment is suitable for such conditions (Regulation 512.1.2 of BS 7671 refers). Where, as is often the case, the equipment is not suitable for these conditions, the current-carrying capacity of the conductors should be based on that given in the relevant table in Appendix 4 of BS 7671 for 70 °C thermoplastic insulated cables of similar construction. Also, where non-sheathed or sheathed cables having different maximum operating temperatures (such as 90 °C thermosetting insulated cables and 70 °C thermoplastic insulated cables) are grouped together, the current-carrying capacity of all the cables in the group must be based on the lowest maximum operating temperature of any cable in the group (Regulation 523.5 refers).

Worked example Solution (1) To carry a current of 30 A continuously or for long periods, the circuit cable must have a current-carrying capacity of not less than 30 A. As indicated in the third paragraph of section 5 of BS 7671 Appendix 4, the current-carrying capacity (Iz) of a cable is given by the formula:

Iz = It x Ca x Cg x Ci Therefore, the minimum acceptable tabulated current-carrying capacity (It) is given by:

It >_

Iz -------------------------------------

Ca x Ci x Cc

So that,

It >_

------------------------------- =

1x1x1

30 A

Table 1 of this article gives assistance in finding the appropriate table of current-carrying capacity in Appendix 4 of BS 7671 where it is necessary to use a thermosetting insulated cable so that its conductor operating temperature will not exceed 70 °C in normal service. The table covers cables with copper conductors only.

From Table 1 of this article, tabulated current-carrying capacities for multicore non-armoured cables to BS 7211 operated at a conductor temperature of 70 °C are given in Table 4D2A of BS 7671 Appendix 4.

Worked example

From column 6 of Table 4D2A, the smallest size of two-core cable giving a tabulated current-carrying capacity (It) of not less than 30 A when clipped direct is 4 mm2 (tabulated currentcarrying capacity 36 A).

Problem A single-phase radial circuit of two-core non-armoured, sheathed thermosetting insulated cables to BS 7211, installed clipped direct, is required to carry a current of 30 A continuously or for long periods. (1) Find the minimum conductor size required if the conductors are to operate at a temperature not exceeding 70 °C in normal service, based on the following assumptions.

• • • •

The circuit length is such that voltage drop need not be considered The circuit is not grouped with any other loaded conductors (grouping rating factor, Cg = 1) The ambient temperature will not exceed 30 °C (ambient temperature rating factor, Ca = 1) The conductors are not installed in thermal insulation (thermal insulation rating factor, Ci = 1)

(2) Also, based on the same assumptions as in (1) above, find the minimum required conductor size if the conductors are permitted to operate at a temperature of up to 90 °C.

The minimum required conductor size such that the conductor operating temperature will not exceed 70 °C is therefore 4 mm2. (Answer)

(2) As shown in column 1 of Table 1 of this article, tabulated currentcarrying capacities for multicore non-armoured cables to BS 7211 where the conductor temperature is not to exceed 90 °C are given in Table 4E2A of BS 7671 Appendix 4. From column 6 of Table 4E2A, the smallest size of two-core cable giving a tabulated current-carrying capacity of not less than 30 A when clipped direct is 2.5 mm2 (tabulated current-carrying capacity 33 A). The minimum required conductor size such that the conductor operating temperature will not exceed 90 °C is therefore 2.5 mm2. (Answer) However, this size of cable would be too small if the operating temperature of the conductors was required not to exceed 70 °C in normal service.

SwitchedOn Issue 19 - Winter 2010

technical Table 1 – List of current-carrying capacity tables in BS 7671 Appendix 4 for operation of thermosetting insulated cables at a conductor temperature not exceeding 70 °C

Note In all cases, to protect the cable against overload current, the coordination requirements of Regulation 433.1.1 must be complied with. For example, if the circuit protective device is a circuit-breaker or fuse of a type listed in Regulation 433.1.2, its rated current or setting (In ) must not exceed the actual current-carrying capacity of the cable, given by

SwitchedOn Issue 19 - Winter 2010

the formula Iz = It x Ca x Cg x Ci , which is 36 A for answer (1) above and 33 A for answer (2). If the protective device is a semi-enclosed fuse to BS 3036, or if the cable is laid in the ground and its tabulated currentcarrying capacity is based on an ambient temperature of 20 °C, the requirements of Regulations 433.1.3 and 433.1.4, respectively, also apply.

ESC WORKING WITH INTERNATIONAL PRODUCT SAFETY PROFESSIONALS he Electrical Safety Council was delighted to work in association with the International Consumer Product Health and Safety Organisation (ICPHSO) to bring its seventh international meeting and training symposium to London.

The symposium was held at the Sheraton Park Lane Hotel from 29-30 November 2010 and was attended by an international delegation with keynote speakers, including the UK’s Parliamentary Secretary for Business, Innovation and Skills, Baroness Judith Wilcox, the Director for Consumer Policy in the Health and Consumers Directorate of the European Commission, Jacqueline Minor and representatives from the EU. In addition, product safety experts from North America, the Asian Pacific, and EU countries were present – 120 in total. The theme of the event Evolution of product safety in the EU and beyond: the threats it faces and its adaptability to the everincreasing supply chain served well to unite the product safety community to discuss and formulate ideas on how to build on the successes achieved over the last 20 years. The general outcome from the open discussions was that, while improvements in product safety continue to be made in individual countries and continents, radical successes will only come from further improvements in co-ordination and cooperation between countries to work together in a truly global way. Throughout the two days of presentations and discussions many aspects of product safety issues and opportunities were explored, including topics focusing on:

Attending the international conference from left to right: Stephen Russell, ANEC; Lina Wilsson Berquist, IKEA; Wayne Morris, AHAM; Marc Schoem, CPSC; Phil Buckle, ESC; and Ron Gainsford, TSI.

• • • • •

Product safety in the EU – progress over the past 20 years Risk communication, product traceability, recall effectiveness, and information exchange Tackling counterfeit products Market surveillance – trends and developments Injury databases and other indicative factors of unsafe products.

The symposium provided a unique opportunity to exchange views and debate with stakeholders, regulators and enforcers from UK, USA, EU, Canada, China,

BACK ISSUES OF SWITCHED ON

Japan, Korea and Australia, as well as with retailers, manufacturers and others in the product supply chain. The Electrical Safety Council led the plenary session on counterfeiting and gave well-received presentations on injury databases and application of EU policy and regulation for electrical products. The conference was a fantastic opportunity for the Council to position itself as a leader in the product safety arena and led to establishing many relationships that will enable it to take the product safety agenda forward during the coming years.

All the previous issues of Switched On are available to read or download from the ‘Business & Community’ section of our website.