Continuously in print since 1952, Modern Wiring Practice has now been fully revised to provide an up-to-date source of reference to building services design and installation in the 21st century. This compact and practical guide addresses wiring systems design and electrical installation together in one volume, creating a comprehensive overview of the whole process for contractors and architects, as well as electricians and other installation engineers. Best practice is incorporated throughout, combining theory and practice with clear and accessible explanation, all within the framework of the Wiring Regulations. Introducing the fundamentals of design and installation with a minimum of mathematics, this book is also relevant reading for all students of electrical installation courses, such as the 2330 Certificate in Electrotechnical Technology, and NVQs from City & Guilds (including 2356, 2391 and 2382 awards), as well as trainees in industry undertaking Apprenticeships and Advanced Apprenticeships. This new edition incorporates the latest thinking on sustainability and the environment and is fully up-to-date with the 17th Edition of the IEE Wiring Regulations. Illustrations have been completely updated to show current best practice and are now in full colour. Reviews of a previous edition: 'This book has long been a favourite of mine. Its regular updating by the issue of new editions ensures it is always completely up to date with the requirements of electrical installation. It is a book that I would thoroughly recommend to any person with an involvement in our industry for it is without doubt one of the very best available, written in a clear and readily understandable manner.' Electrical Contractor 'Refreshingly practical. This book will prove useful to anyone involved in the design and installation of electrical systems: from the apprentice to the architect.' Electrical Review * Brought fully in line with the 17th Edition IEE Wiring Regulations * This well established and renowned book has been continuously in print since 1952 * Incorporating all the latest best practice and illustrated with new colour photographs
Modern Wiring Practice Design and Installation Revised edition W.E Steward and R.A Beck Edited by T.A Stubbs With additional contributions by W.P Branson AMSTERDAM BOSTON HEIDELBERG LONDON NEW YORK OXFORD PARIS SAN DIEGO SAN FRANCISCO SINGAPORE SYDNEY TOKYO Newnes is an imprint of Elsevier Newnes is an Imprint of Elsevier Linacre House, Jordan Hill, Oxford OX2 8DP, UK The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, UK 30 Corporate Drive, Suite 400, Burlington, MA 01803, USA First edition 1952, Fourteenth edition published 2010 Copyright Ó 2010, W.E Steward & Tim Stubbs, additional material by Rob Beck Published by Elsevier Ltd All rights reserved The right of Author Name to be identified as the author of this work has been asserted in accordance with the Copyright, Designs and Patents Act 1988 No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means electronic, mechanical, photocopying, recording or otherwise without the prior written permission of the publisher Permissions may be sought directly from Elsevier’s Science & Technology Rights Department in Oxford, UK: phone (+44) (0) 1865 843830; fax (+44) (0) 1865 853333; email: permissions@elsevier.com Alternatively you can submit your request online by visiting the Elsevier web site at http://elsevier.com/locate/permissions, and selecting Obtaining permission to use Elsevier material Notice No responsibility is assumed by the publisher for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions or ideas contained in the material herein Because of rapid advances in the medical sciences, in particular, independent verification of diagnoses and drug dosages should be made British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging-in-Publication Data A catalog record for this book is availabe from the Library of Congress ISBN–13: 978-1-85617-692-7 For information on all Newnes publications visit our web site at books.elsevier.com Printed and bound in Italy 10 11 12 13 14 10 Acknowledgements We are grateful to many people for assistance with the preparation of this work: firstly, to the Institution of Engineering and Technology for much helpful advice, and for permission to publish extracts from the Wiring Regulations The Regulations are published as a British Standard, BS 7671, and we are equally indebted to the British Standards Institution for their permission to publish extracts This book is not a replacement for the IEE Regulations, and copies of these and the guidance notes which accompany them may be obtained from the Institution at Michael Faraday House, Six Hills Way, Stevenage, SG1 2AY Many companies and individuals in the field of electrical design and installation work have been instrumental in assisting and giving advice which has helped in the preparation of this edition We would particularly like to acknowledge contributions from Amtech Power Software, the British Standards Institution, the Chartered Institution of Building Services Engineers, Cooper Lighting and Safety, M W Cripwell Ltd, the Institution of Engineering and Technology, Inviron, W.T Parker Ltd, Relux Informatik AG., and Wrexham Mineral Cables Our numerous questions have been answered fully and courteously and this help has enabled me to present a practical and up-to-date volume Many of the on-site photographs have been possible thanks to the agreement of individual electricians and designers, to whom we are most grateful In addition to the above we would like to thank a number of electrical equipment suppliers and individuals who have kindly supplied illustrations and photographs These are individually credited To one and all, we extend our appreciation and thanks x Modern Wiring Practice – W.E Steward William Edward Steward was a remarkable man in many ways Trained as a premium electrical apprentice with Mann Egerton at Norwich, he became an electrician, foreman and, later, the branch manager at the firm’s London office In 1933, acting on advice from his brother, he founded William Steward and Company, engaged on a range of mechanical and electrical contracting works In the early days he was company secretary, accountant, chief engineer, estimator, electrician, gas fitter and van driver! The firm became a limited company in 1935 and in 1939 was accepted as a member of the Electrical Contractors Association By adapting readily to changing trading conditions, the business was kept busy during the war and continued its growth in the years which followed The company grew steadily from its early days and employee numbers reached 50 in the 1940s, 100 in the 1950s and over 500 by 1975 Many prestigious contracts were undertaken and by 1985, the company had branches in London, xi xii Modern Wiring Practice – W.E Steward Birmingham, Ipswich, Leeds, Manchester, Norwich, Southampton, Stroud and Walsall, as well as a number overseas William Steward died in 1984 and in 1992 the company was sold and became part of the European electrical giant ABB, being renamed ABB Building Technologies The blend of personal service and professionalism that had been evident from the earliest days was still a feature of the business A management buy-out of ABB Building Technologies in 2003 created a new company, Inviron, which continues to undertake electrical and mechanical engineering activities, along with facilities management It is one of the only (and largest) wholly employee-owned service providers of its kind in the UK In the 1950s, William Steward was an important employer and figure in electrical contracting, and showed a deep commitment to the well being and future of the industry and the people who worked in it It was apparent that a handbook for use by electricians, foremen, managers and designers was needed, and the result was the publication of the first edition of ‘Modern Wiring Practice’ with William Steward himself as author The book has continued ever since and is now in its 14th edition It is pleasing to note that the ethos of William Steward is embraced by Inviron which continues to prosper and whose vision ‘to become the most respected building services provider in the UK’ is a fitting reflection of the philosophy held by William Steward Preface This book surveys the broad spectrum of electrical design and installation work, and this edition has been revised to incorporate the latest amendments to BS 7671 (The IEE Wiring Regulations) issued in 2008 The book is intended to supplement the various regulations and items of legislation It is not a replacement for them The book is divided into two sections: (1) design of electrical installation systems and (2) practical installation work The design section, which has been completely revised to reflect current practice, explains in simple terms the various regulations and requirements and goes on to deal with such matters as the fundamental principles, the design process, installation design, distribution and a design worked example The practical section, dealing with the most important wiring systems, is based on the authors’ experience, and includes many on-site diagrams and photographs The authors hope that readers will gain much useful information from the book Any comments on the new edition will be most welcome R.A Beck T.A Stubbs ix Contents Preface Acknowledgements Modern Wiring Practice – W.E Steward ix x xi Part I Design of Electrical Installation Systems Regulations Governing Electrical Installations Planning of Installation Work The Electricity Safety, Quality and Continuity Regulations 2002 1.3 IEE Wiring Regulations – BS 7671 1.4 The Electricity at Work Regulations 1989 1.5 British Standards 1.6 The Low Voltage Electrical Equipment (Safety) Regulations 1989 1.7 The Work at Height Regulations 2005 1.8 Health and Safety at Work Act 1974 1.9 The Construction (Design Management) Regulations 2007 1.10 Building Regulations 2000 1.1 1.2 11 15 16 16 16 18 20 Fundamental Principles 25 2.1 Protection for Safety Fundamental Principles 2.2 Design Fundamental Principles 25 33 The Design Process 47 3.1 The Stages of Design 3.2 The Components of the Design Process 47 51 Installation Design 57 4.1 Load Assessment and Maximum Demand 4.2 Circuit Design 4.3 Earthing 57 61 82 v vi Contents 4.4 Other Considerations 4.5 Design by Computer Distribution of Supplies in Buildings 5.1 5.2 5.3 5.4 5.5 5.6 5.7 Incoming Supply Main Switchgear Final Circuit Switchgear Circuit Protective Devices (CPDs) Cabling and Distribution Final Circuits Circuits Supplying Motors Worked Example 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 6.10 Design Criteria Process of Design Selection of Switchgear Preliminary Sub-main Cable Sizing Selecting the CPD Sizes Select the Cable Type and Installation Method Voltage Drop Prospective Fault Currents Containment Sizing Final Circuits 88 96 101 101 103 111 115 120 123 131 139 139 141 151 154 157 158 160 162 169 172 Special Types of Installation 181 7.1 Locations Containing a Bath or Shower 7.2 Swimming Pools and Other Basins and Rooms Containing a Sauna 7.3 Construction and Demolition Site Installations 7.4 Agricultural and Horticultural Premises 7.5 Electrical Installations in Caravan Parks, Caravans and Motor Caravans 7.6 Marinas and Similar Locations 7.7 Medical Locations 7.8 Solar Photovoltaic (PV) Power Supply Systems 7.9 Other Special Installations 182 183 183 185 186 187 188 188 188 Part II Practical Work A Survey of Installation Methods 197 8.1 Cable Management Systems 8.2 Foundations of Good Installation Work 8.3 Methods of Installation 197 202 209 vii Contents Conduit Systems 9.1 9.2 9.3 9.4 9.5 10 An Overview of Conduit Installation The Screwed Steel Conduit System Screwed Copper Conduit Insulated Conduit System Cables in Conduits Trunking Systems 10.1 10.2 10.3 10.4 10.5 11 12 13 14 215 227 229 229 235 241 241 242 246 254 254 Busbar and Modular Wiring Systems 255 11.1 Busbar System 11.2 Modular Wiring System 255 259 Power Cable Systems 261 12.1 Armoured, Insulated and Sheathed Cables 12.2 Cable Tray, Cable Basket and Cable Ladder 261 266 Insulated and Sheathed Cable Systems 273 13.1 Surface Wiring 13.2 Concealed Wiring 273 275 Installation of Mineral Insulated Cables 281 14.1 14.2 14.3 14.4 14.5 14.6 14.7 15 An Overview of Trunking Installation Metallic Trunking Non-metallic Trunking Cable Ducts Underfloor Trunking Systems 215 Fixing Bonding Preparation of Cable End Sealing Cable Ends Current Ratings of Cables Some Practical Hints Inductive Loads 281 283 285 287 288 288 289 Luminaires, Switches, Socket Outlets and Data Circuits 291 15.1 15.2 15.3 15.4 15.5 15.6 Ceiling Roses Luminaires and Lampholders Flexible Cords Socket Outlets and Plugs Switches Data Circuits 291 291 294 295 297 299 viii 16 Contents Inspection and Testing 301 16.1 Introduction 16.2 Initial Verification 16.3 Periodic Inspection and Testing 301 302 312 Appendix Appendix A – Extract from IEE Tables Appendix B – Glossary of Terms Index 319 327 329 ... 2.2 Design Fundamental Principles 25 33 The Design Process 47 3.1 The Stages of Design 3.2 The Components of the Design Process 47 51 Installation Design 57 4.1 Load Assessment and Maximum Demand... factories and offices Management and design of installations Installation practice Electrical equipment Regulation Administered by Electricity Safety, Quality and Continuity Regulations 2002 and amendments... managers and designers was needed, and the result was the publication of the first edition of ? ?Modern Wiring Practice? ?? with William Steward himself as author The book has continued ever since and is