Sparks winter 2015 by SNG Publishing

Essential Reading for Apprentice Electricians

MAGAZINE YOUR COURSE COMPANION Terms 3&4 WInter Issue 2015

www.sparks-magazine.co.uk for news, reviews and competitions

TO ® P U P STE RO P D N A MBERL

O E 15 T G A P SEE PAIR WIN A

IN THIS ISSUE...  LEVELS 2 & 3 COURSE TOPICS COVERED  WE LOOK FORWARD TO THE REGIONAL HEATS OF THE

Candidate Name:

MEGGER NATIONAL APPRENTICE COMPETITION 2015 Headline Sponsor

Silver Sponsor

PLUS THIS ISSUE IS BURSTING WITH HELPFUL TIPS! EAL OFFER EXAM ADVICE ON PAGE 3 WHILST WERA TOOLS PROVIDE TOOL TIPS ON PAGE 8

Course:

College:

Price: £2.00

VDE TORQUE DRIVER

The Wera VDE Adjustable Torque Screwdriver is the revolutionary new tool that has been sought by electricians for years. The Kompakt VDE Torque Driver ensures safe working on components with loads up to 1,000 volts. With fully interchangeable blade system, and spin sleeve for fast & accurate operation.

Available individually or in a Kompakt pouch set

TORQUE TOOL

It doesn’t require external tools to adjust the torque setting, which covers the all-important 1.2Nm-3.0Nm range.

SPEED

An unlimted torque optionallows manual loosening work.

UNLOCK

ULTRA COMPACT

Accuracy: +/- 6%

is also prevents users from stripping the insulation during use.

EXTRA SLIM

For more details visit wera-tools.co.uk or search for ‘WeraToolsUK’ on Facebook or Twitter.

VDE EXTRA-SLIM

EXTRA SLIM

UNLOCK

ULTRA COMPACT

Extra-Slim blades with integrated insulation allow access to RCBO’s, recessed screws & spring clamps. Kraftform Plus VDE Extra-Slim screwdrivers and Kompakt interchangeable blades are available individually or in sets.

EXTRA SLIM

CONTENTS

Essential Reading for Apprentice Electricians

MAGAZINE YOUR COURSE COMPANION Terms 3&4 WInter Issue 2015

Price: £2.00

WHAT’S IN THIS ISSUE OF

www.sparks-magazine.co.uk for news, reviews and competitions

TO STEP UP D PRO® RLAN TIMBE

PAGE

office@sng-publishing.co.uk

PAGE

E 15 TO SEE PAG PAIR WIN A

Technical Contributor Mike Davies Electrical Engineer & Lecturer

SYLLABUS

FEATURES

09 12 16 18 20 22 24 28 30 31 32 34 35 38 40 42 44 46 48

MAGNETISM & ELECTROMAGNETISM DEFINING TERMS MECHANICS HEALTH & SAFETY QUIZ SELECTING DATA USING THE IET ON-SITE GUIDE THREE-PHASE ALTERNATING CURRENT ENVIRONMENTAL LEGISLATION CABLE SUPPORTS 3-HEAT SWITCHING MATCHING QUANTITY & UNIT CABLE CAPACITIES OF CONDUIT & TRUNKING ELECTRICAL TEST INSTRUMENTS LIGHTING CALCULATIONS AC MOTORS USEFUL FORMULAE ALTERNATING CURRENT - INDUCTANCE INITIAL VERIFICATION THREE-PHASE POWER SUPPLY MATCHING QUANTITY & UNIT

EAL PROVIDE THEIR TOP TEN EXAM TIPS

NATIONAL COMPETITION SPONSORS

NATIONAL APPRENTICE OF THE YEAR 2015 HEATS GET UNDERWAY SOON

TOOL TIPS FROM WERA TOOLS

CERTSURE REVIEW THE NEW AMENDMENT 3

TIMBERLAND PRO® HIGHLIGHT THE IMPORTANCE OF GOOD QUALITY PPE

REGULARS

02 49

NEWS PRODUCTS & SERVICES

IN THIS ISSUE...  LEVELS 2 & 3 COURSE TOPICS COVERED  WE LOOK FORWARD TO THE REGIONAL HEATS OF THE

Candidate Name:

MEGGER NATIONAL APPRENTICE COMPETITION 2015 Headline Sponsor

Silver Sponsor

PLUS

Course:

College:

THIS ISSUE IS BURSTING WITH HELPFUL TIPS! EAL OFFER EXAM ADVICE ON PAGE 3 WHILST WERA TOOLS PROVIDE TOOL TIPS ON PAGE 8

Editor

Advertising

Graphic Design Studio 74 www.studio-74.co.uk

Publisher Celia Matthews celia@sng-publishing.co.uk

Printers Woodford Litho Ltd England General Enquiries To subscribe to SPARKS Magazine call 0870 774 3049 or subscribe online at www.sparks-magazine.co.uk

DISCLAIMER SPARKS Magazine is published by SNG Publishing Ltd (SNG). All content and artwork is © SNG Publishing Ltd or its contributors and SNG is a trade mark of SNG Publishing Ltd. No part of SPARKS Magazine may be copied, transmitted or published in any form or by any means without prior permission. Although SNG has made every effort to ensure the accuracy of this publication, it does not verify any claims or other information appearing in the advertisements contained in SPARKS Magazine. It therefore cannot accept any responsibility whatsoever for consequences that may arise from the content or artwork contained in SPARKS Magazine, including any errors or omissions or any opinions or advice given therein. This publication and its content is not a substitute for professional advice on a particular matter. Advertisements are accepted for publication in SPARKS Magazine only upon SNG Publishing Ltd standard terms of advertising.

PAGE

Carlie Cohen editor@sng-publishing.co.uk

Note from the Happy New Year! Entries have now closed for this year’s Megger National Apprentice of the Year competition and we’re very much looking forward to all of the upcoming heats and seeing what this year’s calibre of apprentices are going to bring to the events. We hope this edition provides you with lots of interesting and helpful support in line with your syllabus. You’ll also

find the latest news stories from across the industry. Don’t forget to make sure that you’re following us on Facebook www.facebook.com/sparksmag and Twitter @sparksmagazine and make sure you enter our Sparks Freebie Friday competitions for some fantastic prizes.

Carlie Cohen (Editor)

Lecturers and students can find the answers to exercises by visiting the SPARKS website, www.sparks-magazine.co.uk

LIKE US ON...

facebook.com/sparksmag

twitter.com/sparksmagazine SPARKS Magazine / 1

INDUSTRY NEWS

SPARKS COMPETITION WINNER Congratulations to Natalie Gardiner, winner of a Commpact Intrusion System from Electronics Line 3000 in last issue’s Sparks magazine. The repeated word from the competition wordsearch last issue was fault. Did you spot it? Don’t forget that you can win great prizes every week on Facebook through our Sparks Freebie Friday competition!

INDUSTRY

SCOLMORE LAUNCHES NEW BUSINESS Unicrimp is the latest new business to emerge from the successful Scolmore Group of companies. Its formation brings to the electrical contracting industry a comprehensive range of cable accessory products that complement Scolmore’s current wiring accessories and lighting portfolios. Launched under the Q-Crimp brand name and available exclusively through the electrical wholesale trade, the product offering comprises an extensive range of cable management consumables. All products within the Q-Crimp range are manufactured under stringent quality control systems and are fully compliant with the very latest industry regulations. The range includes cable ties, crimp terminals, PVC tape, copper tube terminals, cable clips, and brass and nylon glands – providing everything required to harness cable between the consumer unit and the end accessory. For more info visit: www.unicrimp.com

NEWS Read the full story in the news section of www.sparks-magazine.co.uk

SCOTTISH SAFETY AWARD FROM ELECTRICAL SAFETY FIRST

FEMALE SPARK APPEARS IN CHILDREN’S BOOK A new children’s book designed to challenge gender stereotypes in the trades sector features NICEIC registered electrical contractor Mandy Reynolds. The Sheffield based contractor has been flying the flag for female electricians in recent years – as a supporter of NICEIC’s Jobs for the Girls campaign and as a contributor to a report about women in the construction industry edited by Meg Munn MP. Now she has been immortalised in print by appearing as a caricature in the new book showing young children that there are all sorts of jobs out there regardless of sex. The book - Yes We Can! - was produced by Sheffield-based charity WEST (Women in Engineering Science and Technology). Visit: www.westskills.org.uk/ yeswecan

2 / SPARKS Magazine

This year Electrical Safety First’s award for Best Electrical Safety Project, at the SELECT Electrotechnical Awards, was won by Fife Council. Held at the Radisson Blu Hotel in the centre of Glasgow, the awards ceremony celebrates the brightest and best of Scottish talent in the electrical sector. Fife Council received the award for an innovative collaboration with Perth and Kinross Council, to improve their electrical inspection regime – a process Perth and Kinross had previously undertaken in their area. The partnership promoted knowledge transfer – including electrical safety awareness – and the cost effectiveness of sharing expertise, in a major maintenance programme for public buildings. For more info visit: www.electricalsafetyfirst.org.uk

ELECTRICIANS FINED AFTER FALSELY ISSUING NAPIT CERTIFICATES NAPIT have welcomed the prosecution of two Newbury electricians for carrying out uncertified work and falsely claiming registration with NAPIT. On 8th September 2014 Jamie Warren and Aaron Howe, who traded as Bright Sparks Electrical, each pleaded guilty to falsely implying NAPIT membership and one offence of failing to provide a Trading Standards Officer with information. They were fined nearly £3,000 in total under the Consumer Protection from Unfair Trading Regulations. The company had advised and installed a new consumer unit with a residual current device and provided their customer with a NAPIT Electrical Certificate for Installations and Modifications and an Electrical Test Sheet. The householder followed this up with NAPIT, who confirmed that neither men nor Bright Sparks Electrical were registered, leaving the customer with no option but to pay another electrician to verify the work. The prosecution occurred as a result of an investigation undertaken by West Berkshire Council’s Trading Standards Service team. Visit: www.napit.org.uk

TOP TIPS

TOP TEN EXAM TIPS FROM EAL Qualifying you for success. Some love them, others hate them. But regardless of how you feel about exams, if you want to pursue a career in the electrotechnical sector the chances are you will need to take them – probably lots of them. At EAL we run 300 exams on an average day, so we know a thing or two about them. That’s why we asked our experts to put their heads together and come up with the ultimate top ten exam tips that will help put a spark in your exam performance. Here’s what they said:

Plan your study time

Give yourself enough time leading up to each exam. You need to be ready for the exam but achieving a balance of having fun, taking breaks and studying is vital. Create a study plan and mark the days you have left until the exam. Using the study plan you can map out your activities and goals, ticking off each goal when you achieve it.

Organise your study space

Try to limit any distractions: unplug your games console and turn off the TV as it’s simply too tempting to stray. It’s also imperative to turn off your mobile phone; it’s one distraction too many. Additionally, good lighting, correct room temperature, a comfortable chair and silence are also recommended.

Use flow charts and diagrams

Visual aids can be really helpful. Use colours and bullet points, underline or bold key information.

Have a go at the online practice exams where possible

Start answering the questions that you feel most confident about

Remember, practice makes perfect, so ensure that you use practice exams to test yourself and familiarise yourself with the different types of questions. A good way to monitor your progress is to ask a family member or friend to test you at regular intervals in the run up to the exam.

There is no need to answer the questions in order. It may help you to get in the ‘zone’ if you tackle the easiest ones first, then move on to the more difficult ones after your brain has ‘warmed up’.

Don’t be afraid to ask the invigilator if you are not clear on a question You don’t want all your hard work going to waste just because you interpreted a question incorrectly. If in doubt, ask the invigilator.

Plan and prepare for your exam day

Don’t leave practical preparations until the day before the exam. Ensure you have all the necessary equipment during revision and use it. Find out the location of the exam room and time of the exam.

10.

Use every minute of the exam

Don’t rush to try and finish early, and if you have time left, review your answers before ending the exam or handing back the paper.

Organise study groups

You may have questions that others have the answers to and vice versa.

Drink plenty of water

Stay hydrated to ensure your brain works best.

ABOUT EAL EAL specialises in developing and awarding qualifications for the engineering, manufacturing, building services and related sectors. Over 100,000 learners embark on an EAL qualification each year. Their qualifications carry weight and respect with employers, bringing them real career benefits. For more information: www.eal.org.uk

SPARKS Magazine / 3

NATIONAL COMPETITION

CONTINUED SUPPORT FROM MEGGER As part of its long-term commitment to supporting the education and development of young people who are training to work in the electrical sector, portable test equipment expert Megger is delighted to be yet again sponsoring the 2015 National Apprentice Electrician of the Year. The award is operated in conjunction with technical colleges, with each college invited to put forward one student who is studying for a Level 3 electrical qualification. “We are delighted to be the lead sponsor for the prestigious award

of Megger National Apprentice Electrician of the Year, which offers an exciting challenge to young people entering our industry,” said Simon Wood, UK Sales Manager at Megger. “As a company we genuinely believe that it’s important to give something back to the industry we operate in, and to provide encouragement for the next generation of technicians and engineers.” “That’s why we’re not only sponsoring the Apprentice of the Year, but also putting a lot of effort into our on-going educational programmes that include the supply of specially prepared teaching materials to colleges, and offering presentations in the colleges, delivered by experts from our technical support and sales teams.”

All finalists will be rewarded with an engraved glass trophy plus equipment and clothing that will be of use to them in their work, and the overall winner will in addition receive £1,000 worth of Megger products. The winner’s college will receive £500 worth of Megger products. For more info on Megger, visit www.megger.com

SCOLMORE GROUP...

HELPING TO SHAPE THE FUTURE Developing new and innovative products that make electrical installation projects quicker and easier to carry out is what Scolmore prides itself on.

We are, therefore, delighted to be getting involved with the UK National Apprentice of the Year scheme and playing our part in developing the talent and skills that will ensure the industry continues to thrive in the future.

electricians who value the flexibility and ‘one-stop solution’ that the comprehensive product range allows. The wiring accessories collection has been developed largely as a modular range based on the large selection of switch modules available in the CLICK Minigrid Module range. The simple, single screw fixing of modules offers the simplest possible means of installing and replacing modules. Click iNELS Radio Frequency Wireless Control System offers a simple and flexible installation option, significant energy savings and easy programming are the key attributes of the system.

Wiring Accessories

Lighting

Click Wiring Accessories remain the number one choice with

Under our OVIA umbrella brand we offer one of the most comprehensive

4 / SPARKS Magazine

ranges of lighting products available from under one roof. These include the Energetic low-energy lamp collection, award-winning Flameguard downlighters and Click Lighting. The latest additions to our lighting ranges include Inceptor Max & Micro - some of the industry’s most sophisticated integrated LED downlights.

Investing in the future We understand the importance of supporting the industry and we are keen to play our part to help the electricians of today and tomorrow to develop their skills and grow their businesses. Visit: www.scolmore.com

NATIONAL COMPETITION

Hitachi Power Tools is proud to inspire the next generation of electrical contractors. Hitachi Power Tools is proud to support and inspire the next generation of electrical contractors and wishes every entrant to the National Apprentice Electrician of the Year the very best of luck. “Learning the trade and the skills associated with it is extremely valuable, both for you personally and for the future of electrical contracting in the UK,” says Simon Miller, brand manager for Hitachi Power Tools. “Having the right tools for the job is important and that’s why Hitachi Power Tools are delighted to be the official power tool supplier to the competition.” Hitachi Power Tools’ 18V 5.0Ah Lithium-ion (Li-ion) cordless range is tougher, faster and more advanced than any of its predecessors. The 5.0Ah range brings the latest brushless motor and advanced electronic control technology together with high performance Li-ion 5.0Ah batteries. This means up to 200% more run time per charge than 3.0Ah batteries while keeping the same size and weight for the tools.

Trade Direct has been insuring trades and construction individuals and businesses for over 30 years, and insure over 40,000 customers from individuals to businesses with up to 15 employees. With this experience we believe that we know the protection that you need, and can help you save money while protecting yourself. Whether you’re newly qualified and starting out, or running a business – our insurance can help protect you through your career. When you’re starting out, you may want to keep costs down, so we offer our Essentials product which is a quality liability product with public liability limits from £1M to £5M. Our next level of cover Classic includes Professional Indemnity cover as well as £1,000 of tools cover included as standard. Our flagship Plus product further extends cover to include Personal Accident. With a quality product, flexible limits, a range of optional cover options and the ability to pay for your insurance by instalments, we’ve got you covered.

“We wish every entrant the very best of luck and we also look forward to making sure Hitachi Power Tools are your tools of choice in your long and successful careers,” continues Simon. “Good luck and we hope to see you at the finals!” For more details and information on the tools available for electrical contractors, visit www. hitachi-powertools.co.uk, follow us on Twitter @HitachiToolsUK and at Facebook.com/ hitachipowertoolsuk

For more information visit: www.tradedirectinsurance.co.uk

Wera supports The National Apprentice of the Year. World-leading manufacturer Wera specialises in screwdriving tools with headquarters in Germany and UK operation in Derbyshire. Wera’s tools are for professional, industrial applications and are a solutionprovider for problems associated with screw-connections. Wera emotionalises and intrigues users consistently with exceptional product ideas. In practical applications these – with many unique features – result in truly outstanding performance. 100% perfect quality is assured through a continually monitored manufacturing process resulting in near zero complaints. Feedback from users is crucial in Wera’s tool designs and to make life easier, faster and safer this input is vital. The electrical / plumbing industries are two of the most regulated from safety aspects and Wera can contribute valuable advice and recommendations from nearly 80 years of experience. Wera are very pleased to be sponsoring and continuing support of The National Apprentice of the Year Awards because it gives the company a chance to have a responsible and productive input into the well-being of our country’s upcoming plumbers and electricians.

For more info information visit www.wera-tools.co.uk

SPARKS Magazine / 5

NATIONAL COMPETITION

AND SO IT STARTS! Entries are now closed for this year’s Megger National Apprentice of the Year competition.

Industry support We thank all of our fantastic sponsors below who are supporting us this year. Not only do we get to see the best apprentices from across the UK, the event is also supported by some of the leading manufacturers in the industry. This year we’re delighted to welcome NICEIC, Wera Tools, Hitachi, Trade Direct Insurance, EAL, Schneider Electric, Knipex, BASEC and Dimplex.

GOLD SPONSOR

Silver Sponsor

Since the announcement of this year’s competition we’ve received lots of entries and we can’t wait to see what this year’s colleges have to offer. The standard of entries gets tougher each year, so our judges are in for a challenging time during the heats! With only one student being put forward from each college, this is set to be a very exciting competition!

6 / SPARKS Magazine

Bronze Sponsors

NATIONAL COMPETITION Winner 2014 Last year’s winner Luke Mayor from Cardiff & Vale College.

WINN E 2014 R

How does the competition work? All students entered will attend one of our six regional heats held at colleges across the country. Winners are chosen at each regional heat with a final overall winner announced. Every entrant will receive tools plus a Certificate of Achievement. We’re delighted to see that the competition is growing year on year. It’s a fantastic opportunity for apprentices, lecturers, manufacturers and leaders from amongst the electrotechnical industry to meet. Don’t forget that if you didn’t get in this year, you can still enter next year’s event as long as you fall within the correct age bracket.

Competition organiser Celia Matthews is publisher of Sparks Magazine, and founder of the Apprentice of the Year competitions. Keen to celebrate the effort and enthusiasm paid by our apprentices she’s looking forward to seeing what this year’s entrants will bring. “Each year we’re so impressed with the standard of competition that we see – good luck everyone!”

SPARKS Magazine / 7

TOOL TIPS

TIPS ON TOOLS Anyone working in the electrical and plumbing industries will know only too well the challenges they face in installing and maintaining equipment and components. Everyone will recognise components are being crammed closer together with reduced working spaces. Other hurdles:  Connections and joints have to be tightened (torqued) to manufacturer’s specifications to prevent under or over-tightening.  Many will not realise the wide variances in screw quality and accuracy of the driving slots and the effect on tool performance. Failure occurs or at least reduced tool service life.  On the flip side, many tools supplied to the market fail to meet standards and in turn compromise safety, job efficiency and connection quality.  Tools are often used intensively and poor designs lead to uncomfortable working conditions and can indeed lead to strain.  Regulations and commercial demands heap on the pressure in working safely and efficiently. This is a fact of life and cannot be sidestepped. Depressing? Relax - life does not have to be so bad! By making informed choices, life can be made so much better. Whether it’s any of the above conditions or others such as increasing productivity and profit or working more efficiently to keep the boss happy, making the correct tool decisions will have a significant effect.

Choose wisely:  Some require additional tools to make the adjustments with – with slower, more awkward operation. Don’t lose the adjuster tool!

protection. Wera’s Lasertip roughened blade tips literally ‘bite’ into screw slots and compensate for reduced contact in poor screw heads.

 A wide adjustment range might seem attractive, but calibration is harder to maintain, so re-calibration is needed more often – more down time and expense.  Any torque over 3Nm in a hand screwdriver handle format is hard to deliver towards near impossible over 4.5Nm. Physical stress is increased; speed and safety may be compromised.  Functionality and ease and speed of use – choose one that does not have to be dismantled and re-assembled each time a torque adjustment is needed. Productivity, speed and ease of use are all compromised.

The industry’s full of Pozi drive and Phillips screws. Just by making sure that the correct driver tip is utilised in the screw head will increase service life. Profile stamping on screwdriver handles help with correct tool selection. The images show the screw differences - they may seem similar, but in reality, they are very different.

Screwdrivers are used daily and expectations of their performance are high. Are they comfortable during intensive use; what’s their service life; and most importantly – how safe are they?

Some tips here will assist choice and users’ satisfaction levels:

Regular and intensive use ‘sorts the men from the boys’ – a multitude of handle designs cannot all be classed as ergonomic, but often are. Ergonomics is a science to reduce physical stress. For instance Wera’s patented Kraftform screwdriver handles are truly born from the shape of the hand, contoured in the right places to reduce pressure spots and to deliver torque effectively and comfortably.

Recessed screws and RCBOs are a problem. A common way to overcome the problem of access to these whilst using insulated blades is to ‘cut back’ the insulation. Ok, so it works, but bear in mind the amount of exposed metal blade is to a standard of safety (VDE 1000v EN 60900;2004) and that has now been destroyed. Additionally, the warranty on the tool is voided. Wera offers screwdrivers that feature integrated insulation where the insulation is no wider than the tip, so no need to ‘peel back’.

Wera’s philosophy demands making life easier, faster and safer for tool users. A current ‘hot topic’ of the industry is the correct torquing to manufacture’s settings of screws in electrical installations. This can only be accurately achieved with an adjustable torque screwdriver and there are a number of those available to buy.

8 / SPARKS Magazine

Connection screw slots vary massively in dimension accuracy due to lack of standards. This cannot easily be avoided so screwdriver tip design and performance is critical for safe screw driving and component

More ‘Tips on Tools’ in the future. For more information, check out www.wera-tools.co.uk

EXERCISE

MAGNETISM & ELECTROMAGNETISM Covering Unit 309, (or EAL equivalent) ‘Understanding the Electrical Principles Associated with the Design, Building, Installation and Maintenance of Electrical Equipment and Systems.’ (Level 3 NVQ Diploma in Installing Electro-Technical Systems and Equipment 2357-13 / 91) A basic knowledge of magnetism and electromagnetism is an essential requirement for understanding electrical machines such as generators and motors. The following revision exercise should help develop your understanding.

Q1. Complete the following statement: In magnetism, LIKE POLES

and UNLIKE POLES

Q2. Show the magnetic lines of force between each of the following permanent magnet poles. a)

Q3. Indicate the direction of magnetic field around the following current carrying conductors. a)

b) Current flowing into conductor

Current flowing out of the conductor

Q4. State the rule that is associated with magnetic fields surrounding current carrying conductors

Q5. If a current carrying conductor is placed at

90º to a magnetic field what is the effect on the conductor?

Q6. If a conductor is passed through a magnetic field in the direction shown what is the effect on the conductor?

Q7. What is the effect on the conductor in question 6 if it is moved upwards through the magnetic field?

Q8. State two hand rules that can be used to determine the direction of force or current flow in a conductor when moved through a magnetic field.

Go to www.sparks-magazine.co.uk to freely download exercise answers SPARKS Magazine / 9

INDUSTRY UPDATES

GET UP TO SPEED WITH AMENDMENT 3 The Third amendment to BS 7671:2008, The IET Wiring Regulations, came into effect on January 1. installation in a dwelling, a documented risk assessment determines that the RCD protection is not necessary. Maximum earth fault loop impedances given in tables 41.2, 41.3, 41.4 and 41.6 have been revised to take account of the Cmin factor. Cmin is the minimum voltage factor to take account of voltage variations depending on a number of considerations.

Electricians now have a six month transition period to get up to speed with the changes as from July 1 it will be a requirement that all electrical installations designed after 30 June 2015 are to comply with BS 7671:2008, incorporating Amendment 3:2015. Here NICEIC and ELECSA provide a summary of the main changes that have come into effect with Amendment 3.

New numbering system The Third amendment recognises UK only regulations and these are now identified by a new numbering system. Regulations with a .100 number are CENELEC requirements and those with a .200 number are specific to the UK.

PART 2 - Definitions Definitions have been expanded and modified, including the introduction of some new symbols. A list of abbreviations used in the Regulations has been added. The definition of ‘competent person’ has been removed and it has been replaced with ‘instructed person (electrically)’ and ‘skilled person (electrically)’. These changes have been reflected throughout the wiring regulations.

CHAPTER 42 - Protection against thermal effects Due to the number of consumer unit fires reported within domestic premises, Regulation 421.1.201 (UK only) has been added and requires consumer units and similar switchgear to have their enclosure manufactured from non-combustible material or be enclosed in a cabinet or enclosure constructed of noncombustible material and complying with Regulation 132.12.

Please note: This regulation does not come into effect until 1st January 2016 to allow for manufacturers to ensure an adequate supply of suitable cabinets or enclosures is available, but this does not preclude compliance with the regulation prior to that date.

CHAPTER 51 - Common rules Section 551 concerning compliance with standards requires all equipment to be suitable for the nominal voltage and also requires certain information to be noted on the Electrical Installation Certificate.

CHAPTER 55 - Other equipment A new section 557 Auxiliary Circuits is included. All auxiliary circuits are defined in Part 2.

SECTION 559 - Luminaires and lighting installation Requirements for outdoor lighting installations and extra low voltage lighting installations have been moved to new Sections 714 and 715 respectively.

PART 7 - Special Installations or Locations Section 701 locations containing a bath or shower. There is now a requirement for RCD protection to be provided for:  low voltage circuits serving the location  low voltage circuits passing through zones 1 and 2 not serving the location.

Appendix 3 - Time / current characteristics of overcurrent protective devices and RCDs This includes changes in connection with maximum earth fault loop impedance to take account of the Cmin factor given in CLC / TR50480:2011.

APPENDIX 6 - Model forms for certification and reporting The schedule of inspections (for new work only) has been replaced by examples of items requiring inspection during initial verifications (which must be appended to the Electrical Installation Certificate). A small number of changes to the Electrical Installation Condition Report and associated notes have been made, including a requirement to carry out an inspection within an accessible roof space where electrical equipment is present in that roof space.

CHAPTER 41 - Protection against electric shock

CHAPTER 52 - Selection and erection of wiring systems

There is now a requirement for RCD protection for socket-outlets up to 20A for all installations, however exceptions are permitted for:  a specific labelled or otherwise suitably identified socket-outlet provided for connection of a particular item of equipment,

A new regulation 521.11.201 (UK only) has been included giving requirements for the methods of support of wiring systems in escape routes.

This summary is an overview of the main changes within Amendment 3 and is not a definitive guide to all the changes introduced by Amendment 3.

The regulations concerning selection and erection of wiring systems have been re-drafted. Reference to “under the supervision of a skilled or instructed person” has been removed.

For more details about how to stay up to speed with the changes or to order your copy of Amendment 3 call NICEIC on 0843 290 3501 or visit www.niceic.com

 or where, other than for an

10 / SPARKS Magazine

EXERCISE

DEFINING TERMS Covering Unit 304 (or EAL equivalent), â&#x20AC;&#x2DC;Understanding the Principles of Planning and Selection for the Installation of Electro-Technical Equipment and Systems in Buildings, Structures and the Environment.â&#x20AC;&#x2122; (Level 3 NVQ Diploma in Installing Electro-Technical Systems and Equipment 2357-13 / 91) The correct use of terms is an important part of your training to be an electrician.

Q1. Try providing your own definition to the following terms. i.

Earthing

ii.

Equipotential bonding

iii. Exposed-conductive-part

iv. Extraneous-conductive-part

Main earthing terminal

vi. Protective conductor

Q2. Look at the key and then add the correct labels to the following block diagram

KEY A: Class I electrical equipment, e.g metal-enclosed washing machine, electric motor, any equipment requiring a circuit-protective-conductor B: Main earthing terminal, (MET) located in the Consumers Control Unit or CCU C: Extraneous conductive part, e.g. water pipe or gas pipe D: Portable class I equipment E: Consumers means of earthing F: Earthing conductor G: Circuit protective conductor H: Main protective bonding conductor

Go to www.sparks-magazine.co.uk to freely download exercise answers 12 / SPARKS Magazine

SUPER PRODUCTS YOU CAN RELY ON

Offering a super selection of quality products for all your wiring requirements

J1522 SPARKS Magazine ad - Super Products.indd 1

27/11/2014 16:12:25

COVER STORY

DON’T FALL FOR SLIPS & TRIPS AT WORK Slips, trips and falls are one of the main causes of workplace fatalities and major injuries in the UK. In 2012 / 2013 alone, they were estimated to have cost the UK economy two million lost working days(1) and were responsible for in excess of 29,000 reported over seven day major injuries or fatality incidents. Statistics aside, sufferers often have to endure pain and discomfort, injury rehabilitation, lost work opportunities and lost income – particularly painful if they are self-employed, so prevention is critical. Here Susan Peverelli, product manager at Timberland PRO®, looks at what can be done to help reduce this major workplace problem.

So how do you help prevent a slip, trip or fall related accident at work? First and foremost, ensure the area in which you or your colleagues are working is tidy and free from slip and trip hazards. The untidier a workplace the greater the accident risk. For those in building and construction or who will be out and about a lot as part of their job, think about the work environment. Will you be in wet, muddy or on uneven surfaces, climbing up and down ladders or stairways, going from dry to wet or having to twist, turn, bend or kneel as part of the job? Identify what the main slip, trip and fall risks are in your work environment and select safety footwear designed to deal with them. To the untrained eye, a lot of safety footwear today looks similar, but under the surface the difference in technical features can be massive and contribute significantly to comfort, well-being and above all else safety. The key is to match the safety footwear performance features to the hazards you will encounter and there are a number of considerations to take into account:  Sole Performance: Think of a sole unit as a tyre tread, designed to provide grip performance and stability. Just as tyres are designed for specific terrains, so too are sole units. The type of hazards, environment and conditions encountered will help determine the required sole unit. Wrong sole unit in the wrong

environment can increase a slip or trip risk. An injected PU/TPU sole unit will provide enhanced grip in addition to high level comfort, shock absorption and greater flexibility. Abrasion resistance within the sole unit is also important feature to look for.

DID YOU KNOW An easy way of identifying if safety footwear has been tested for slip resistance is to check its coefficient of friction (CoF) test values. The higher the CoF, the better the slip resistance. Look for CoF results higher than the minimum requirements set out in EN ISO 20345/6/7. Footwear passing the EN slip resistance test will be marked with one of the following codes, SRA (tested on ceramic tile wetted with dilute soap solution), SRB (tested on smooth steel with glycerol) or SRC (tested under both conditions).  Physical Protection: If there is a danger from heavy or sharp objects dropping onto, or piercing the footwear ensure that appropriate physical protection measures are in place. This includes toe and ankle protection, pierce resistant sole units and scuff caps.  Durability: Opt for premium materials such as high quality leathers made in the manufacturing process (in the uppers and the sole unit) as this will increase the durability of the footwear and in turn the lifespan. Attention to detail will also have a benefit. Look for additional stitching and flexible reinforcements on the toe caps and heels to reduce wear and tear.  Comfort: Critical not just for worker well-being but also for accident prevention avoid heavy, cumbersome or inflexible safety footwear which increases foot fatigue. The latest innovations in the market include anti-foot fatigue systems, enhanced insoles and the

use of breathable technical fibres designed to provide temperature control with the addition of antibacterial and moisture absorption performance to manage perspiration within the footwear. Consider composite metal-free safety footwear which is also lighter. Look for ergonomically designed padded collars which will increase comfort around the ankle particularly when flexing or kneeling when working.  Combining Style, Quality and Substance: More than ever before, safety footwear manufacturers are looking at high street style and are incorporating this into their designs to reflect growing customer demand. For leading brands, this emphasis on style is always combined with the development of critical safety performance features as highlighted above. Manufacturers such as Timberland PRO® also work closely with customers to create new products that meet specific industry needs or provide solutions to key hazards and put an emphasis on quality and product development. Look for manufacturers that can demonstrate this attention to detail, creation of innovative solutions and focus on quality.

Conclusion Slips, trips and falls are extremely difficult to manage, given the way people work and the environments in which that work is carried out. PPE should always be the last line of defence, but where it is necessary, it is essential to take time to know the hazards of the workplace and select the right solutions. For more information on the full Timberland PRO® range, available under exclusive licence from Honeywell Safety Products Europe in EMEAI, the World’s largest provider of head to toe personal protective equipment (PPE) solutions, visit the website at www.timberlandpro.eu

REFERENCE: 1) http://www.hse.gov.uk/statistics/causinj/slips-trips-and-falls.pdf

14 / SPARKS Magazine

EXERCISE

MECHANICS Covering Unit 309 (or EAL equivalent) â&#x20AC;&#x2DC;Understanding the Electrical Principles Associated with the Design, Building, Installation and Maintenance of Electrical Equipment and Systems.â&#x20AC;&#x2122; (Level 3 NVQ Diploma in Installing Electro-Technical Systems and Equipment 2357-13 / 91) The electrical engineer may be required to use his / her mechanical skills to overcome various problems such as finding a suitable method of securing a trunking or cable tray to a wall or suspended from a roof structure. The following problems introduce you to basic mechanics:

Q1. Identify the direction in which the following

Q2. Identify the direction in which the final

Q3. Indicate the direction of rotation for each of

Q4. Show the resulting direction of movement

levers will move when pressure is applied in the direction of the arrow.

the pulleys shown below.

wheel will turn.

for the following crank levers.

Go to www.sparks-magazine.co.uk to freely download exercise answers 16 / SPARKS Magazine

DONâ&#x20AC;&#x2122;T MISS IT! The National Apprentice of the Year Competition is about to begin! Come along and watch the top regional electrical trainees go head-to-head as they battle it out to win the enviable title of National Apprentice of the Year 2015.

HEADLINE SPONSOR

HEATS WILL TAKE PLACE AT THE FOLLOWING VENUES NORTH WEST: NORTH EAST: SOUTH WEST: SOUTH EAST: MIDLANDS: WALES:

18th February 2015, Burnley College 20th February 2015, New College Durham 26th February 2015, Weston College 10th March 2015, Prospects College of Advanced Technology 24th March 2015, Stephenson College 14th April 2015, Bridgend College

The National Final will be held at Birmingham Electrical Training on 19th and 20th May 2015.

Check out www.sparks-magazine.co.uk for more info

EXERCISE

HEALTH & SAFETY QUIZ Covering Unit 301 (or EAL equivalent), ‘Understanding Health and Safety Legislation, Practices and Procedures (Installing and Maintaining Electro-Technical Systems and Equipment.’ (Level 3 NVQ Diploma in Installing Electro-Technical Systems and Equipment 2357-13 / 91) Using the letter and number codes to match the abbreviation with the correct meaning.

HASAWA

Health and Safety Executive

CDM

Mobile Elevating Work Platform

PUWER

Reporting of Injuries, Diseases and Dangerous Occurrences Regulations

HSE

Personal Protective Equipment

RIDDOR

Construction (Design and Management) Regulations

COSHH

Approved Codes of Practice

MEWP

Provision and Use of Work Equipment Regulations

PPE

Respiratory Protective Equipment

RPE

Control of Substances Hazardous to Health

ACoP

Health & Safety at Work Act 1974

CHECK

10 = Go to www.sparks-magazine.co.uk to freely download exercise answers

18 / SPARKS Magazine

DV18DGL/JF

All New 18V Combi Drill With 55Nm Hard Torque

EXERCISE

ELECTRICAL SUPPLY SYSTEMS: SELECTING DATA USING THE IET ON-SITE GUIDE Covering Unit 304 (or EAL equivalent) ‘Understanding the Principles of Planning and Selection for the Installation of Electro-Technical Equipment and Systems.’ (Level 3 NVQ Diploma in Installing Electro-Technical Systems and Equipment 2357-13 / 91) Understanding principles for selecting cables and circuit protective devices. For each of the following state the specific function of the components:

Q1a.

Distributor’s cut-out

Q1b.

Electricity meter

Q1c.

Consumers control unit

Q1d.

Electricity isolator switch

Q1e.

Main earthing terminal

Go to www.sparks-magazine.co.uk to freely download exercise answers 20 / SPARKS Magazine

THE POWER TO SUPPORT YOU ALL THE WAY

the power behind your business Each year we support over 36,000 electrical contractors and renewable energy installers with technical advice, training, news and discounts on a wide range of products and services. Let us get behind you from day one of your career. To find out how to join us call 0843 290 3392 or visit us at.

niceic.com

elecsa.co.uk

EXERCISE

THREE-PHASE ALTERNATING CURRENT Covering Unit 309 (or EAL equivalent) â&#x20AC;&#x2DC;Understand the Electrical Principles Associated with the Design, Building, Installation and Maintenance of Electrical Equipment and Systems.â&#x20AC;&#x2122; (Level 3 NVQ Diploma in Installing Electro-Technical Systems and Equipment 2357-13 / 91) The following questions concern three-phase a.c. supply systems.

Q1. Complete the missing words and symbols on the following diagram. U1 or Sometimes the symbols L1, L2 and L3, rather than U1, U2 and U3, are used to identify phases.

phase

Neutral

volts

U2 or

phase

U3 or

phase

400 V

Q2. Complete the missing word or words in the following statements: a) The diagram in question 1 shows the

of a three-phase transformer.

b) The voltage measured between a phase and the neutral conductor is called the is identified by the symbol

c) The voltage measured between any pair of phases is called the the symbol

Q3a. State the formula used to convert line voltage to a phase voltage in a three-phase system.

Q3b. The voltage measured

and . and is identified by

between two lines of a three-phase supply system is 400V. What is the voltage measured between one line and neutral of the same supply?

Q3c. The phase voltage of a

three-phase system is 240V. What is the line voltage of the same system?

Go to www.sparks-magazine.co.uk to freely download exercise answers 22 / SPARKS Magazine

e b o t g n i n i Tra ? n a i c i r t c e l e an

e h t e v a h We r o f s tool . b o j the er y v e t a s t c rodu p 0 0 0 , 1 1 ore m 0 Over 0 0 , 3 r ove S U L P . e r o st day! t x e n e l b availa

EXCLUSIVE to qualified Electricians (or 2nd year relevant students) Reasons to Join: Additional specialist ranges at low fixed Ex VAT trade prices. Dedicated Trade team.

at Available om c screwfix. r & at ove s 360 store de nationwi

To find out more about becoming a member of Electricfix, pop into your local Screwfix store.Text 78777 to find your nearest store or contact your call centre on 0808 172 7000 Mobile Friendly Number 03330 112 333

EXERCISE

ENVIRONMENTAL LEGISLATION, WORKING PRACTICES & PRINCIPLES OF ENVIRONMENTAL TECHNOLOGY SYSTEMS Covering Unit 302 (or EAL equivalent) ‘Understanding Environmental Legislation, Working Practices and the Principles of Environmental Technology Systems.’ (Level 3 NVQ Diploma in Installing Electro-Technical Systems and Equipment 2357-13 / 91) Try these multiple-choice questions. Attempt ALL questions.

The disposal of transformer oil with general landfill waste material may result in the contamination of:

Atmosphere and water courses

Land and water courses

Air and water

Land and atmosphere

Ans.

Q6 a

Lead

Copper

Mercury

Bronze

Q7 Q2

One factor that determines whether a product is classified as hazardous waste is if it is:

Ans.

A material known as a ‘heavy’ metal is: Ans.

An essential requirement when working with PVC conduit adhesive is to:

Keep the lid on the adhesive container at all times

Non-combustible

Only use in outdoor locations

Corrosive

Ensure it is compatible with the conduit

Fine particles

Provide good ventilation

Inert

The Act that defines limits for emissions of products into the environment is the:

Q8 Ans.

The electrical contractor is responsible for waste disposal and recycling:

Up to the end of the contract

Building Act

Up to the location allocated for collection from site

Prevention of Polluting Substances Act

Until the material is collected from site

Environmental Protection Act

Health & Safety at Work Act

Unless stated in the contract that waste will not be an issue

The WEEE directive applies to electrical equipment that operates at voltages of up to and including:

1000V a.c.

500V a.c.

230V a.c.

100V a.c.

Non-hazardous waste materials include:

Batteries

Plastic

Lead

Paper

Ans.

Rubber

Porcelain

Lead

Asbestos Waste generated on a construction site can be reduced by:

Using sub-contractors

Working quickly and efficiently

Careful planning

Removing waste to a designated storage area

Go to www.sparks-magazine.co.uk to freely download exercise answers 24 / SPARKS Magazine

Ans.

In old industrial locations where rewireable fuses were used, one Ans. hazardous material likely to be found is:

Q10

Ans.

EXERCISE

A serious oil leak on site that is

Q11 likely to have an impact on the

environment should be reported:

Immediately

In writing

At the next site meeting

After attempts to reduce the impact have been taken

To reduce the impact on the Q12 environment caused by fire, one method is to install cables with: a

PVC insulation

Low smoke and fume insulation

Silicon rubber sheath

Polyethylene sheath

To ensure the generation of waste

Q13 material is kept to a minimum, one action to be taken is:

Ans.

Q16

The most common type of wind turbine in use today is the:

Vertical shaft type

Split shaft type

Horizontal shaft type

Dynamic shaft type

Q17

One disadvantage of a solar heating system is the:

Low running cost

High emission

Renewable energy

Long payback time

Q18

The output of a ground source heat pump is suitable for:

Electricity generation

Store all products safely so they are not damaged and become waste products

Under-floor heating

Delivered to site as required

Hot water

Stored on site until needed

General wet type central heating systems

Delivered at the start of the contract

The output power from a solar PV Q14 installation can be connected to the public power supply through a: a

Static converter

Rotary converter

Static inverter

Rotary inverter

Q19 Potable water is: Ans.

Clean water

Pure water

Wholesome water

Safe water

In a hydro generator system the water pressure is used to drive a:

Ans.

Q20 to provide a useful voltage, panels are connected in:

Generator

Parallel

Alternator

Series

Motor

Star

Turbine

Delta

Ans.

Solar PV panel outputs are small, so

Q15

Ans.

Continued on page 26

Go to www.sparks-magazine.co.uk to freely download exercise answers SPARKS Magazine / 25

EXERCISE

Q21 A heat pump produces:

Ans.

Q26

Hazardous materials must be disposed of by:

Electricity

Warm air

Main contractor

Gas

Authorised contractor

Hot water

Sub-contractor

Client

A heating system that derives its

Q22 source fuel from landfill sites is called:

Ans.

One method of reducing power consumption for lighting is to Q27 install lamps with a lumen per watt efficacy of:

Biomass

Bioliquid

Biogas

Biofuel

Q23

Micro CHP systems generally have an Ans. output of approximately:

One factor that determines whether

Q28 a substance is hazardous waste is if it is:

1kW

2kW

Flammable

5kW

Chemical

10kW

Organic

Metallic

The installation of environmental technology systems in existing Q24 premises requires consultation before installation, with the: a

Health & Safety Executive

Local Planning Authority

Water Utility Company

Local residents

Q25 Grey water can be collected from a:

Ans.

Q29

A wind turbine converts wind energy into:

Electrical energy

Rotating mechanical energy

Kinetic energy

Heat energy

Q30

A hydro-generator producing an output of 80kW is classed as a:

Shower

Mega-hydro system

Toilet

Micro-hydro system

Laundry

Hydro system

Bath

Large hydro-system

Go to www.sparks-magazine.co.uk to freely download exercise answers 26 / SPARKS Magazine

Ans.

EXERCISE

CABLE SUPPORTS Covering Unit 305 (or EAL equivalent) ‘Understanding the Practices and Procedures for the Preparation and Installation of Wiring Systems and Electro-Technical Equipment in Buildings, Structures and the Environment.’ (Level 3 NVQ Diploma in Installing Electro-Technical Systems and Equipment 2357-13 / 91) Electric cable can be constructed in many forms:- non-sheathed, sheathed, armoured, metal covered and so on. The way in which a cable should be installed depends on the wiring system that has been chosen by the designer.

Q1. Complete the following table. TYPE OF CABLE

METHOD OF INSTALLATION

PRECAUTIONS WHEN INSTALLING OR IN USE

Non–sheathed

Sheathed

Armoured

Flexible

Metal sheathed

Go to www.sparks-magazine.co.uk to freely download exercise answers 28 / SPARKS Magazine

EXERCISE Q2. Complete the following table of cable-clip spacings. CABLE

HORIZONTAL SPACING

VERTICAL SPACING

NON-ARMOURED SHEATHED

Diameter: 1cm

FLAT TWIN & EARTH 9mm

18mm

PVC SWA 25MM DIA.

45째

Cable

MICC 9.5MM DIA.

Dia.

Go to www.sparks-magazine.co.uk to freely download exercise answers SPARKS Magazine / 29

EXERCISE

HEATER CIRCUITS: 3–HEAT SWITCHING Covering Unit 306 (or EAL equivalent), ‘Understanding the Principles, Practices and Legislation for Termination and Connection of Conductors, Cables and Cords in Electrical Systems.’ (Level 3 NVQ Diploma in Installing Electro-Technical Systems and Equipment 2357-13 / 91) Medium Low

High

Off

Where different heat settings may be required, for example in a convector heater or electric hot-plate, one method is to switch heating elements. If the convector heater or hot-plate is fitted with two sets of resistance elements it will be possible to switch them either in series, parallel or as a single resistance using a 3-heat switch.

3-heat switch A 3-heat switch will have an OFF position, a LOW, MEDIUM and HIGH

heat setting. Each position is selected by turning the knob to the required position. The internal switching mechanism will connect line and neutral to specific terminals, (labelled 1, 2, 3, and 4 in the circuit diagram). More than one switch connection can be made in any position, e.g. contact 1 may connect to contact 4 and at the same time contact 3 may connect with contact 2, and so on.

Q1. Complete the circuit diagram showing how the 3-heat switch should be connected to obtain low, medium and high heat settings.

Element 1

Element 2

4 L

Q2. For each setting, complete the following information table. SETTING

SWITCH TERMINAL CONNECTIONS

HEATING ELEMENT CONNECTION ARRANGEMENT (SERIES, PARALLEL, SINGLE RESISTANCE)

Low

Medium

High

Go to www.sparks-magazine.co.uk to freely download exercise answers 30 / SPARKS Magazine

EXERCISE

MATCHING QUANTITY AND UNIT Covering Unit 309 (or EAL equivalent) ‘Understand the Electrical Principles Associated with the Design, Building, Installation and Maintenance of Electrical Equipment and Systems.’ (Level 3 NVQ Diploma in Installing Electro-Technical Systems and Equipment 2357-13 / 91) The following terms all relate to electrical quantity and its corresponding unit. Try to match the following quantities to their respective units.

QUANTITY

UNIT

Frequency

Farad

Capacitance

Newton

Energy

Ohm

Force

Newton-metre

Charge

Weber

Reactance

Hertz

Torque

Henry

Resistivity

Ohm / Metre

Magnetic Flux

Joule

Mutual Inductance

Coulomb

CHECK

10 = Go to www.sparks-magazine.co.uk to freely download exercise answers SPARKS Magazine / 31

EXERCISE

CABLE CAPACITIES OF CONDUIT & TRUNKING Covering Unit 304 (or EAL equivalent), â&#x20AC;&#x2DC;Understanding the Principles of Planning and Selection for the Installation of Electro-Technical Equipment and Systems.â&#x20AC;&#x2122; (Level 3 NVQ Diploma in Installing Electro-Technical Systems and Equipment 2357-13 / 91) If thermosetting cables are installed in the same trunking or conduit as thermoplastic insulated cables, the conductor operating temperature of any cable must not exceed that stated for the thermoplastic insulated cables. For these questions refer to the IET On-Site Guide BS7671:2008 (2011) Appendix E.

Q1a. What is the difference between thermosetting and thermoplastic PVC insulation?

Q1b. Appendix E concerns cable capacities for three specific cases: i.

Straight runs of conduit not exceeding

ii. Straight runs of conduit exceeding or

in length. in length, or in runs of any length with .

iii. Trunking.

Q2. Find and state the cable factors for each of the following cable types and installation methods. i.

2.5mm2 PVC insulated cable with solid conductors installed in a straight length of galvanised steel conduit.

ii. 10mm2 PVC insulated cables with stranded conductors installed in a 2m length of galvanised steel conduit.

iii. 10mm2 PVC insulated cables with stranded conductors installed in a 4m length of galvanised steel conduit.

Go to www.sparks-magazine.co.uk to freely download exercise answers 32 / SPARKS Magazine

EXERCISE Q3. Determine a suitable size of conduit to accommodate the following sized cables in a 2.8m straight run of steel conduit. i. iii.

Q4.

3 x 1.5mm2 (stranded conductors) 1 x 10.0mm2

ii. iv.

3 x 4.0mm2 2 x 16.0mm2

Determine the number of 25mm2 cables that can be installed in a 25mm dia. conduit.

Q5. The next questions concern cables installed in a steel conduit that is 5m in length with one 90ยบ bend and two off-sets. (Note: one off-set is equivalent to one bend)

Determine a suitable size of conduit to accommodate the following sized cables in the conduit. i. 3 x 1.5mm2 (solid conductors)

Q6.

ii. 3 x 4.0mm2 (solid conductors)

iii. 2 x 10.0mm2 (stranded conductors)

Determine the number of 16mm2 with thermosetting insulation that can be installed in a 50mm x 50mm galvanised steel trunking.

Q7. What is the minimum inner bend radius for a 25mm conduit?

Go to www.sparks-magazine.co.uk to freely download exercise answers SPARKS Magazine / 33

EXERCISE

ELECTRICAL TEST INSTRUMENTS Covering Unit 309, (or EAL equivalent) ‘Understanding the Electrical Principles Associated with the Design, Building, Installation and Maintenance of Electrical Equipment and Systems.’ (Level 3 NVQ Diploma in Installing Electro-Technical Systems and Equipment 2357-13 / 91) In the following exercise match the actual value to the standard form for that value.

NO.

TEST INSTRUMENT FUNCTION AND READING

Current 2 x 102 Voltage 33 x 103 Resistance 200 x 106 Current 30 x 10-3 Resistance 50 x 103 Power 6 x 103 Power 6 x 106 Voltage 400 x 106

MEASURED UNIT

0.030A

50000Ω

6000W

200000000Ω

6000000W

33000V

200A

400000000V

CHECK

1 =

8= Go to www.sparks-magazine.co.uk to freely download exercise answers

34 / SPARKS Magazine

EXERCISE

LIGHTING CALCULATIONS: Covering Unit 309, (or EAL equivalent) ‘Understanding the Electrical Principles Associated with the Design, Building, Installation and Maintenance of Electrical Equipment and Systems.’ (Level 3 NVQ Diploma in Installing Electro-Technical Systems and Equipment 2357-13 / 91) POINT-TO-POINT LIGHTING PROBLEMS. REVISION: TASK 1 Artificial light can be produced in one of two ways:  By passing a current through  By passing an electric current through The passage of current through a tungsten filament causes the filament to heat-up to about 2500ºC. At this temperature, a considerable amount of heat is produced and an amount of light. This is called

If current is made to pass through a gas or metallic vapour, such as mercury, light will be produced. This is called .

Point-to-Point Point-to Point calculations are concerned with the amount of light at the lamp, the distance the light source, or lamp, is located away from the surface to be illuminated and the amount of light actually falling on the surface.

LIGHTING TERMINOLOGY Q1. Define the following terms and show the symbol that represents the unit and / or quantity. TERM

DEFINITION

UNIT/S

Luminous Intensity

Luminous Flux

Illuminance

Luminaire

Luminous Efficacy Continued on page 36

Go to www.sparks-magazine.co.uk to freely download exercise answers SPARKS Magazine / 35

EXERCISE

THE INVERSE SQUARE LAW Light Source

The illuminance on a surface produced from a single light source reduces the further away from the light source the surface is situated. The actual reduction is such that it reduces by the square of the distance as shown by the formula:

E = I / dÂ˛

Flow of Light

This is called the Inverse Square Law and is applicable to a point immediately beneath the light source as shown. Illumination

300cd EXAMPLE: The intensity of a light source is 300cd and is located perpendicular to a surface 4m from it.

E = I / d2 E = 300 / 42

E = 18.75 lx

What is the illuminance at the surface?

Q2. Calculate the illuminance if the surface is 5m away from the source. 300cd

Go to www.sparks-magazine.co.uk to freely download exercise answers 36 / SPARKS Magazine

EXERCISE

THE COSINE LAW Light Source

The illuminance at point other than that immediately below the light source can be found by applying the Cosine Law. θ

Flow of Light

EB = (I / h2) x Cos θ h

To find h use Pythagoras Theorem: h = √ d2 + x2 To find the Cosine of the angle (θ): Cos θ = d / h

Height (d) Illumination Distance (x)

EXAMPLE: EB = (I / h2) x Cos θ 300cd

θ 3m

To find h use Pythagoras Theorem:

To find the Cosine of the angle (θ):

h = √ d2 + x2 h = √ 32 + 42 = √ 25 h = 5m

Cos θ = d / h Cos θ = 3 / 5 Cos θ = 0.6

Therefore: EB = (I / h2) x Cos θ EB = (300 / 52) x 0.6 EB = 7.2 lx

Q3. Calculate the illuminance at point EB. 1000cd

θ 5m

Go to www.sparks-magazine.co.uk to freely download exercise answers SPARKS Magazine / 37

EXERCISE

AC MOTORS REVISION PRACTICE Covering Unit 309, (or EAL equivalent) ‘Understanding the Electrical Principles Associated with the Design, Building, Installation and Maintenance of Electrical Equipment and Systems.’ (Level 3 NVQ Diploma in Installing Electro-Technical Systems and Equipment 2357-13 / 91) The following multiple choice questions relate to electric motors. The terms, ‘stator’ and ‘rotor’ are

Q1 normally associated with which one of the following?

Ans.

The slip speed of a single-phase

Q6 induction motor is stated to be 0.02p.u. What does this mean in real terms?

Direct current generators

0.2% slip

Alternating current generators

2.0% slip

Direct current motors

20 rpm

Alternating current motors

2 rpm

A motor data plate indicates that it is

Q2 an eight–pole machine, which one of the following statements is correct?

Ans.

To increase motor torque without increasing the physical size of the rotor, which one of the following is recommended?

The motor has four pairs of poles

The motor can be connected to a d.c. supply

A wound rotor

The motor needs a single-phase power supply

A cage rotor

The motor has eight magnetic fields

A double-cage rotor

A solid rotor core and copper windings

Which of the following statements best describes an AC induction motor?

The motor has an armature and field windings

The motor requires a variable power supply

The motor has a stator and a rotor

The motor always has a wound rotor To reverse the direction of rotation of

Q4 a three-phase induction motor which of the following actions is required?

Reverse connect any two lines of the three phase supply

Reverse connect one of the stator windings

Reverse connect the rotor

Reverse connect (+) and (-) of the supply

A three-phase induction motor has four–poles and is connected to a supply at 50Hz. What is the synchronous speed of the motor?

Ans.

Which one of the following rules can be used to describe the principle of electro-magnetic induction in the rotor of an ac motor?

Flemings Left-Hand Rule

Flemings Right-Hand Rule

The Right-Hand Grip Rule

The Right-Hand Grasp Rule

Ans.

The reason for laminating the stator and Ans. rotor cores of induction motors is to:

Help reduce torque

Allow the escape of heat

Reduce the current induced in the rotor

Reduce eddy currents The wound–rotor is connected to

Q10 externally located resistances by the use of?

3000 rpm

A commutator

1500 rpm

Split-copper conductors

1000 rpm

Slip-rings

750 rpm

Steel end rings

Go to www.sparks-magazine.co.uk to freely download exercise answers 38 / SPARKS Magazine

Ans.

QUICK TEST

TEST YOUR KNOWLEDGE NUMBER SEARCH – British & European Standards Try to locate the following BS and BS EN numbers in the grid. (Numbers can be found vertically and horizontally from left to right)

1 9 2 4 7 6 2 1 0 3 6 2 3 4 7 5 2 6 2 8 9 1 3 6 8 2 1 0 0 4 0 5 3 1 5 0 3 7 5 3 8 4 1 7 0 9 1 6 4 3 7 2 4 6 4 7 1 3 6 1 3 4 2 7 2 6 8 6 1 1 7 7 5 2 0 6 8 3 2 8 4 3 0 5 0 5 2 7 4 4 6 1 0 1 7 6 5 1 7 8 6 5 1 0 3 8 2 3 8 1 2 8 4 3 0 3 6 6 7 0 2 1 7 5 9 1 3 2 6 5 1 8 1 6 7 2 1 6 6 0 6 0 1 3 9 9 6 1 0 2 6 2 1 0 7 7 1 2 3 2 3 2 2 4 1 3 7 4 0 1 5 2 6 3 0 1 7 6 0 8 3 0 5 4 2 1 9 4 0 4 0 6 0 7 5 6 5 4 5 4 5 9 3 2 8 3 6 0 3 0 9 4 1 7 9 3 4 0 8 8 0 7 3 1 1 9 6 8 5 2 8 5 1 9 7 2 0 1 8 1 8 5 0 1 0 9 3 4 9 0 6 0 8 0 9 3 4 6 2 7 0 7 2 8 2 9 5 7 6 3 9 6 8 7 2 7 5 4 0 5 6 5 1 0 1 5 8 5 0 7 9 1 1 6 7 3 8 9 3 4 0 1 3 1 0 1 3 7 2 6 3 2 7 3 1 1 9 3 0 4 0 5 2 9  BS 67 ceiling rose

 BS EN 60898 CBs

 BS EN 61009 RCD

 BS 1363 13A sockets

 BS 951 bonding clamp

 BS 1362 fuse links

 BS EN 61000 EMC

 BS 7671 IET Regs

 BS EN 60309 sockets

 BS EN 61558 transformers

 BS EN 60601 medical

 BS EN 50266 fire test

 BS 88 fuses

 BS 1361 cartridge fuse

 BS 3036 fuses

 BS7540 cables

Go to www.sparks-magazine.co.uk to freely download exercise answers

SPARKS Magazine / 39

EXERCISE

USEFUL FORMULAE FOR CITY & GUILDS 2357-13 UNIT 309 (OR EAL EQUIVALENT) Below is a summary of formulae needed for the Science and Principles unit. V = IR or U = IR

RESISTANCE: SERIES:

RT = R1 + R2 I = V ÷ RT or I = U ÷ RT pd1 = I R1 pd2 = I R2 V = pd1 + pd2

pd1

pd2 V or U

PARALLEL:

1/RT = 1/R1 + 1/R2 Or when two resistors are in parallel use RT = Product ÷ Sum or RT = R1 + R2 ÷ R1 x R2 IT = I1 + I2 IT = V ÷ RT I1 = V ÷ R1 I2 = V÷ R2

I2 R2 V or U

RESISTIVITY OR CONDUCTOR RESISTANCE:

R = ρL ÷ a

remember ρ (rho) is the specific resistance of the conductor material, (L) is length of conductor in metres and (a) is the cross-sectional-area of the conductor.

AC CIRCUITS: I

Resistive

V and I are ‘in-phase’ and I = V ÷ R Phasor diagram

Inductive

L I

I lags V by 90° L is inductance in Henry’s Inductive reactance XL = 2πfL V

V I lags V by 90°

Capacitive

C I

I leads V by 90° C is capacitance in Farads Capacitive reactance XC = 1 ÷ 2πfC Or when C is in µF then XC = 106 ÷ 2πfC I leads V by 90°

V V

Various combinations can be made resistance and inductance, (R-L), resistance and capacitance, (R-C), or resistance, inductance and capacitance (R-L-C), series circuits.

Go to www.sparks-magazine.co.uk to freely download exercise answers 40 / SPARKS Magazine

EXERCISE L

R-L CIRCUIT:

I R

NOTE: I is common throughout the circuit VR will be in-phase VL

I will lag VL by 90°

Total impedance (Z) is found from: Z = √R2 + XL2 I = VS ÷ Z VR = IR VL = IXL Phase angle θ = VR ÷ VS

IMPEDANCE TRIANGLE:

VS VL

I Reference line Phase angle θ

By taking the Phasor diagram for the R-L circuit and highlighting the sides that make up a triangle, we can indicate the sides of the triangle that represent R, L and Z in the circuit; this produces the Impedance Triangle. VS VL Z

XL R

Impedance Triangle

Phasor Diagram

Phasor diagrams, impedance triangles and power triangles, (see below), all rotate anti-clockwise from their point of origin

POWER FACTOR:

It can be seen that power factor (pf) can be determined by: pf or cos θ = VR ÷ VS (from the Phasor diagram) or pf = R ÷ Z (from the impedance triangle)

POWER TRIANGLE:

If Power (P) can be found from V x I then it is possible to show that power can be calculated from each side of the impedance triangle, BUT each power will be determined differently and will represent a different aspect of the circuit. True Power in Watts is found from P = V x I and is the resistive part of the circuit (R) Apparent Power in VoltAmps (VA) = V x I x cos θ and relates to the overall impedance of the circuit (Z) Reactive Power in VoltAmpsReactive (VAr) = V x I x tan θ True Power W Phase Angle θ Apparent Power VA

Reactive Power VAr

NOTE: Power Factor is normally lagging, therefore the triangle is shown in this format with the Apparent Power below the True Power.

Go to www.sparks-magazine.co.uk to freely download exercise answers SPARKS Magazine / 41

EXERCISE

ALTERNATING CURRENT (AC): INDUCTANCE Covering Unit 309, (or EAL equivalent) â&#x20AC;&#x2DC;Understanding the Electrical Principles Associated with the Design, Building, Installation and Maintenance of Electrical Equipment and Systems.â&#x20AC;&#x2122; (Level 3 NVQ Diploma in Installing Electro-Technical Systems and Equipment 2357-13 / 91) TASK 1: Complete the missing words and symbols. Inductive reactance: (symbol

) measured in: (unit

symbol

Remember when a coil of wire such as a winding in a motor, transformer or choke, (ballast), is connected to an alternating current supply, opposition to current flow is caused by two conditions, these are? a)

b) This combination results in the effect called of the a.c. supply and the

and will depend on the of the coil.

TASK 2: Label the following diagram using correct terms at (i), (ii) and (iii).

(ii)

(iii)

(i)

State the formula for inductive reactance and make a key stating the name and unit symbol for each relevant part of the formula. FORMULA:

KEY:

Go to www.sparks-magazine.co.uk to freely download exercise answers 42 / SPARKS Magazine

)

EXERCISE TASK 3: Complete the following practice questions: Q1. Calculate the inductive reactance of a coil of 0.23H when it is connected into an a.c. circuit operating at 50Hz.

Q2. A coil has 200V measured across it and a current of 1.75A flowing through it when connected to a 50Hz a.c. supply. Determine the value, (or rating), of the inductor, in Henrys.

Q3. Determine the current flowing through a coil of 0.65H when connected to a 230V 60Hz a.c. supply.

Q4. Calculate the voltage across an inductor of 0.25H when the current flowing through it is 2.65A at 48Hz.

Go to www.sparks-magazine.co.uk to freely download exercise answers SPARKS Magazine / 43

EXERCISE

INITIAL VERIFICATION OF ELECTRICAL INSTALLATIONS Covering Unit 307 (or EAL equivalent) ‘Understand Principles, Practices and Legislation for the Inspection, Testing Commissioning and Certification of Electro-Technical Systems and Equipment in Buildings, Structures and the Environment.’ (Level 3 NVQ Diploma in Installing Electro-Technical Systems and Equipment 2357-13 / 91) TASK 1: Complete the following questions regarding the principles, practices and legislation for the initial verification of electrical installations. (Refer to the IET Guidance Note 3 for precise answers)

Q1. State two occasions when initial verification can be carried out. a)

Q2. Identify two aspects of BS 7671 that initial verification will confirm.

Q3. When an inspector carries out an initial verification, explain why inspection and testing can only be ‘so far as is reasonably practicable’?

Q4. Identify the three BS 7671 generic requirements for items to be verified during the initial verification procedure.

b) c)

Q5. State the correct title of the statutory document that concerns inspection and test records, AND identify the length of time records must be kept.

Go to www.sparks-magazine.co.uk to freely download exercise answers 44 / SPARKS Magazine

EXERCISE Q6.

Briefly explain the meaning of the term â&#x20AC;&#x2DC;relevant criteriaâ&#x20AC;&#x2122; in respect to the initial verification process.

Q7.

State who is responsible for comparing and verifying inspection and test results with relevant criteria for an installation.

Q8.

State the correct titles of three certificates that apply to a new installation or additions to an existing installation. a)

b) c)

Q9.

List three items of required information regarding the assessment of general characteristics for an installation. a)

b) c)

Q10. The Health and Safety at Work Act 1974 requires relevant information to be available for what purpose?

Go to www.sparks-magazine.co.uk to freely download exercise answers SPARKS Magazine / 45

EXERCISE

THREE-PHASE POWER SUPPLIES

Star and Delta Connections and Formulae Covering Unit 309 (or EAL equivalent) ‘Understand the Electrical Principles Associated with the Design, Building, Installation and Maintenance of Electrical Equipment and Systems.’ (Level 3 NVQ Diploma in Installing Electro-Technical Systems and Equipment 2357-13 / 91) Three-phase AC motors and transformers can be connected so that the full mains supply is connected across each winding, or across two windings.

TASK 1: Complete the missing words and symbols. STAR CONNECTION: One end of each winding is connected to a common point called the FIG. 1

Formulae:

VL = √3 x VP IL =

L3 VOLTAGE measured across a single winding is the phase voltage ( (L1, L2 or L3) is the

), the voltage measured between

(VL).

CURRENT flowing in each single winding is the phase current (IP) and the current flowing in each line conductors is the line current (IL).

TASK 2: Show the line and phase currents and voltages on figure 1 above. Q1. By using the formula shown in figure 1, complete the following. i) Calculate the phase voltage when the line voltage is stated to be 400V.

ii) Three 200Ω resistances are connected in star formation. If the phase voltage is 240V calculate the line current flowing.

Go to www.sparks-magazine.co.uk to freely download exercise answers 46 / SPARKS Magazine

EXERCISE TASK 3: Complete the missing words and symbols. DELTA CONNECTION: When connected in delta, each winding is connected to a pair of lines.

FIG. 2

Formulae:

VL = IL = â&#x2C6;&#x161;3 x IP

VOLTAGE measured across a winding is the

voltage (

), the voltage

measured between the lines (L1, L2 or L3) is the line voltage (VL). CURRENT flowing in each winding is the phase current (IP) and the current flowing in the line conductors is the line current (IL).

Q1. By using the formula shown in figure 2, complete the following. i) Calculate the phase current when the line current is found to be 50A.

ii) Three 100ÎŠ resistors are connected in delta. If the line voltage is 400V calculate the phase current and line current that is expected to flow.

Go to www.sparks-magazine.co.uk to freely download exercise answers SPARKS Magazine / 47

EXERCISE

MATCHING QUANTITY AND UNIT Covering Unit 309 (or EAL equivalent) ‘Understand the Electrical Principles Associated with the Design, Building, Installation and Maintenance of Electrical Equipment and Systems.’ (Level 3 NVQ Diploma in Installing Electro-Technical Systems and Equipment 2357-13 / 91) The following terms all relate to the quantities and units used in electrical engineering. Try to identify the correct quantity for each unit given.

UNIT NAME OR SYMBOL

Quantity

Impedance

Magnetic Field Strength

Weber

Reactance

Resistivity

Coulomb

Electric Field Strength

Magnetic Flux

Charge

Rho

Self-inductance

Candela

Weight

Luminous Intensity

CHECK

10 = Go to www.sparks-magazine.co.uk to freely download exercise answers

48 / SPARKS Magazine

PRODUCTS & SERVICES

ADVERTISING IN SPARKS MAGAZINE If you would like the professional electricians of the future to know about your products or services, why not advertise in this section? It’s cost effective and your brand will reach around 12,000 electrotechnical students throughout the UK. Please send your press releases to Carlie Cohen at: editor@sng-publishing.co.uk If you would like to book a display advertisement in Sparks Magazine, please contact Celia Matthews:

T. 0870 774 3049 E. celia@sng-publishing.co.uk

HITACHI POWER TOOLS LAUNCHES 18V ANGLE DRILL

WILD WEATHER GLOVES FROM SNICKERS WORKWEAR

Hitachi Power Tools has launched its new DN18DSL/L4 angle drill weighing just 1.7kg. With a class-leading low centre height of 23mm for easier working in confined spaces, it has an impressive torque of 12Nm, controlled by a variable speed paddle switch. Hitachi has also included a white LED work light and a battery life indicator. It benefits from a soft grip body, and a detachable side handle gives extra control. The tool features a 10mm keyless single sleeve chuck and a handy belt hook that can be fitted either left or right. The DN18DSL/L4 angle drill accepts all Hitachi 18V Li-Ion slide batteries from 1.5Ah to 5.0Ah and, subject to terms and conditions, is backed by a three-year warranty which must be registered online within 28 days of purchase. For more info check out www.hitachi-powertools.co.uk

Pioneering gloves from Snickers Workwear - optimum grip, maximum power, complete comfort. There’s no doubt that the most important tools that you have on site are your hands! That’s why it’s so important to make sure they are properly looked after during the winter months. Snickers now have a range of work gloves that cope with even the harshest of weather conditions. From tough, hard-wearing ‘Weather Essential Gloves’ to ‘Weather Cut Protection Gloves,’ these top-quality Snickers products will keep your hands properly protected and warm. There are 8 different styles in the range that will suit all types of working environment and weather condition. Typical of these bad weather gloves is the ‘Weather Dry Glove,’ which is made from advanced materials to deliver precise dexterity, friction and grip even in wet, cold and slippery conditions. Visit www.snickersworkwear.co.uk

HULTAFORS TOOLS - NEW TOOLS CATALOGUE

SNICKERS XTR SHIELD - REDEFINING WORKWEAR

This full colour brochure is now available FREE to professional tradesmen around the UK. Packed with details of loads of innovative hand tools and accessories for working effectively, wherever you are on site. Everything in the Hultafors Tools range bears the hallmarks of a company that has over 100 years’ experience in knowing what it takes to get a job done efficiently, effectively and safely. Proof of Hultafors’ quality and innovation can be found in every hand tool. Ergonomically crafted with built-in Fisco technology, there’s a host of tools for measuring and marking, chopping, striking and levelling. So, whatever job you’ve got in hand, these hand tools deliver top-class solutions for making your workday easier. So get to grips with this cutting-edge range of tools – you’ll be amazed how good it really is!

Revolutionary indoor and outdoor working clothes from Snickers. With 40 years’ experience of designing and manufacturing market-leading working clothes for professional tradesmen and women, every new product it launches continues to raise the bar on standards of functionality and quality. The pioneering XTR Shield jackets, trousers and kneepads are super-light working clothes that act as a lightweight protective shield around your body, allowing you to move seamlessly between indoor and outdoor work. With advanced technology fabrics, these clothes deliver great comfort and limitless functionality. The trousers provide breathable, windproof and waterproof protection with superior knee protection and comfort. Similarly, the jacket creates a super-light, maxi-comfort shield around your body that follows your every move on site. Count on superior protection, all year round!

T. 01484 854788  www.hultafors.co.uk

Visit www.snickersworkwear.co.uk

Email editor@sng-publishing.co.uk if you would like your product or service featured in this section.

Looking for an electrical apprenticeship? We work with over 120 employers in the Birmingham area to place apprentices.

Call 0121 616 0700 or visit our website: www.birminghamelectricaltraining.co.uk

VDE

www.knipex.de

Apart from the pliers the assortment of KNIPEX insulated tools also includes everything necessary for electricians like ratchets, open end wrenches, box wrenches or nut drivers.

KNIPEX – VDE Range Insulated tools – a question of trust The KNIPEX VDE range encompasses everything that the electrician needs when working on live installations. In addition to products from the world of pliers, tools such as single open ended spanners, box wrenches, nut drivers, ratchets etc. are also available as insulated tools. KNIPEX insulated tools are safety-tested, one by one Every single pair of pliers leaving our factory is first tested at a voltage of AC 10,000 V. This represents a test load that is 10 times the maximum voltage permitted when working. This safeguards the user when working. You can depend on KNIPEX tools in every situation.

KNIPEX Quality – Made in Germany

For more details about the KNIPEX range of tools, and for details of your nearest stockist please contact: Alex Garami – 0777 543 74 69 a.garami@knipex.com