Design of Electrical Services for Buildings

318 Pages·2007·4.81 MB·English

by  Barrie Rigby

Design of Electrical Services for
Buildings, 4th Edition

Design of Electrical Services for
Buildings, 4th Edition
Barrie Rigby

LONDON AND NEW YORK
First published 1974 by Chapman and Hall Ltd Second edition published by 1982 Third edition
published 1989 Reprinted 2001 by Spon Press
Fourth Edition published 2005 by Spon Press 2 Park Square, Milton Park, Abingdon, Oxon 0X14
4RN
Simultaneously published in the USA and Canada by Spon Press 270 Madison Ave, New York,
NY 10016
Spon Press is an imprint of the Taylor & Francis Group
This edition published in the Taylor & Francis e-Library, 2005.
“To purchase your own copy of this or any of Taylor & Francis
or Routledge’s collection of thousands of eBooks please go to
http://www.ebookstore.tandf.co.uk/.”
© 1974, 1982, 1989, 2005 Barrie Rigby
All rights reserved. No part of this book may be reprinted or reproduced or utilised in any form or
by any electronic, mechanical, or other means, now known or hereafter invented, including
photocopying and recording, or in any information storage or retrieval system, without permission
in writing from the publishers.
Every effort has been made to ensure that the advice and information in this book is true and
accurate at the time of going to press. However, neither the publisher nor the authors can accept
any legal responsibility or liability for any errors or omissions that may be made. In the case of
drug administration, any medical procedure or the use of technical equipment mentioned within
this book, you are strongly advised to consult the manufacturer’s guidelines.
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 Rigby, Barrie. Design of electrical services
for building/Barrie Rigby.—4th ed. p. cm. Earlier editions were authored by Fred Porges.
Includes bibliographical references and index. I. Buildings—Electric equipment. I.Porges, F.
(Fred). Design of electrical services for building. II Title. TK4001.R54 2004 621.319¢24—dc22
2004002487
ISBN 0-203-45684-X Master e-book ISBN
ISBN 0-203-34117-1 (Adobe e-Reader Format)
ISBN 0-415-31082-2 (hbk)
ISBN 0-415-31083-0 (pbk)
Contents

Preface to third edition vi
Preface to fourth edition viii

1 Accessories 1
2 Cable 29
3 Wiring 42
4 Cable rating 69
5 Circuits 77
6 Distribution 86
7 Lighting 103
8 Power 128
9 Protection 131
10 Fire alarms 164
11 Call and computer systems, telephone and public address systems 175
12 Reduced-voltage systems 185
13 Communal and closed-circuit TV systems 188
14 Lightning protection 212
15 Emergency supplies 228
16 Lifts, escalators and paternosters 235
17 Regulations 262
18 Design example 265

Bibliography 303
Index 304
Preface to third edition

This book sets out to provide a basic grounding in the design of electrical services for
buildings. It is intended for students of building services engineering in universities and
polytechnics but will also be useful to graduates in mechanical and electrical engineering
who are about to specialize in building services after obtaining a more broadly based,
first degree. The emphasis throughout is on the needs of a design engineer rather than on
those of an installation electrician or of an architect.
Engineering is one discipline, but with the increasing number of specialized first
degree courses, the requirements for greater flexibility among engineers within industry
have increased commensurably; many young graduates find themselves called on to work
in fields not fully covered in their studies. In spite of the many opportunities which now
exist for continuing professional education there is still a lack of books to bridge the gap
between the theoretical texts and the unwritten experience of one’s predecessors. It was
in the hope of meeting this need that I originally wrote this book, and I believe the need
still exists sufficiently to justify this new edition.
Opinions will always differ about the order in which the topics within the subject
should be taken. I have retained the order of the previous editions, which was based on
my own view that it is confusing to try to explain distribution without first saying to what
the supply has to be distributed. Those who find a different order clearer may prefer to
read the chapters out of sequence. A number of changes and additions have been made in
this edition to keep up with the changes in practice; the section on hazardous areas has
been expanded, the chapter on lighting has been considerably rewritten to bring the
information on mercury and sodium discharge lamps up to date, and the chapter on
lightning protection has been revised to take account of the new British Standard. To
make this clearer, calculation examples have also been added. Sections have been added
on the application of solid state electronics to fire alarms and to lift controls and the
chapter on emergency supplies now includes uninterruptible power supplies. Elsewhere
changes have been in terminology. Thus fused spur units have become fused connection
units and earth leakage circuit breakers are now residual current circuit breakers.
There is a chapter on the form and function of the IEE Regulations, but I have not
attempted any commentary on them. The intention of this book is to provide something
more than a gloss on the regulations: A book which hopes to cover the complete design
of an electrical installation must include many things not dealt with by regulations and
should be free to follow its own methods and sequence. Once this was done there was
nothing to be gained by covering the same ground a second time in the form of a
commentary or explanation of the regulations.
The subject matter of this book is the design of electrical services in buildings and I
have kept strictly to this. There are in practice many cases where the electrical designer
relies on information and assistance from specialists in related but separate fields. This
applies in particular to controls for heating and air conditioning, which are designed by
specialists in that field and not by the consultant or contractor employed for the general
electrical system. A description of them would, therefore, be out of place here. Many
other services within a building include electrical equipment but the principles of motors,
thermostats and controls are major studies of their own. Electric heating undoubtedly
uses electricity but its design requires a knowledge of heating and ventilating. All these
are topics which embrace more than the purely electrical work within a building and if
they are to be dealt with properly they must have books of their own. Whilst appreciating
that they may well form part of a complete engineering course I do not think they can all
be covered in one book, and rather than treat them superficially and incompletely, I have
left them out altogether.
I must again thank the many firms and organizations which have lent or given
photographs for illustrations and to the staff of the publishers for help and guidance with
the intricacies of revising an existing book for a new edition. In particular I would thank
the editorial and production staff and Phillip Read at E. & F.N.Spon. On this occasion it
is an added pleasure to be able to acknowledge the typing skills of Sonia Porges.
Fred Porges
Harrow
Preface to fourth edition

Much of what the late Fred Porges wrote as the preface to the previous edition still holds
true. In this edition I have attempted to keep to the format of previous editions. With
systems becoming more sophisticated, it is enough for the building services engineers to
be reasonably aware of the systems in use, and the duties that they perform. Without the
need for the engineer to be familiar with the intricacies of the electronic circuits. There
are many building services design software packages on the market today, but the
engineer still needs to know the basics of what they output and how the values are arrived
at. The pace of change of legislation, introduction of European Standards, is ever
increasing. I have left the academic parts of the book virtually unchanged, with the
exception of changes in terminology. Other parts of the book have been completely
overhauled to reflect modern practices and techniques. In particular I would thank the
editorial and production staff at E. & F.N.Spon. I would also like to thank my dear wife
and family for their support while I have been updating this book.
Barrie Rigby
Ulverston