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Wiring Regulations in Brief
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About the author
Ray Tricker (MSc, IEng, FIET, FCMI, FIQA, FIRSE) is the Principal Consultant of
Herne European Consultancy Ltd – a company specialising in ISO 9000 Management
Systems- is also an established Butterworth-Heinemann author (18 titles). He served
with the Royal Corps of Signals (for a total of 37 years) during which time he held vari-
ous managerial posts culminating in being appointed as the Chief Engineer of NATO’s
Communication Security Agency (ACE COMSEC).
Most of Ray’s work since joining Herne has centred on the European Railways. He has
held a number of posts with the Union International des Chemins de fer (UIC) (e.g.
Quality Manager of the European Train Control System (ETCS)) and with the European
Union (EU) Commission (e.g. T500 Review Team Leader, European Rail Traffic
Management System (ERTMS) Users Group Project Co-ordinator, HEROE Project Co-
ordinator) and currently (as well as writing books on diverse subjects as Optoelectronics,
Medical Devices, ISO 9001:2000 and Building Regulations for Elsevier under their
Butterworth-Heinemann and Newnes imprints!) he is busy assisting small businesses
from around the world (usually on a no-cost basis) produce their own auditable Quality
and/or Integrated Management Systems to meet the requirements of ISO 9001:2000,
ISO 14001 and OHSAS standards etc. He is also a UKAS Assessor for the assessment
of certification bodies for the harmonisation of the trans-European high-speed railway
network.
To Claire
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Wiring Regulations in Brief
A Complete guide to the requirements of the
16th Edition of the IEE Wiring Regulations,
BS 7671 and Part P of the Building
Ray Tricker
AMSTERDAM ● BOSTON ● HEIDELBERG ● LONDON
NEW YORK ● OXFORD ● PARIS ● SAN DIEGO
SAN FRANCISCO ● SINGAPORE ● SYDNEY ● TOKYO
Butterworth-Heinemann is an imprint of Elsevier
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Butterworth-Heinemann is an imprint of Elsevier
Linacre House, Jordan Hill, Oxford OX2 8DP
30 Corporate Drive, Suite 400, Burlington, MA 01803
First published 2007
Copyright © 2007, Raymond L. Tricker. Published by Elsevier Ltd.
All rights reserved.
The right of Raymond Tricker 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:
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Contents
Preface xix
Acknowledgements xxv
Further information xxvii
1 Introduction 1
1.1 Introduction 1
1.2 Historical background 2
1.3 What does the standard contain? 4
1.3.1 What about the standard’s numbering system? 6
1.4 What are the objectives of the IEE Wiring Regulations? 6
1.5 What is the legal status of the IEE Wiring Regulations? 7
1.6 What does it cover? 7
1.6.1 Electrical installation 7
1.6.2 Electrical equipment 9
1.7 What affect does using the Regulation have on
other regulations? 10
1.7.1 The Building Act 1984? 10
1.7.2 The Disability Discrimination Act 2005 11
1.7.3 The Electricity at Work Regulations 1989 11
1.7.4 The Fire Precautions (Workplace) Regulations 1997 14
1.7.5 The Health and Safety at Work Act 1974 14
1.8 How are the IEE Wiring Regulations implemented? 15
1.8.1 Statutory Instruments 15
1.8.2 CENELEC Harmonised Documents 17
2 Domestic buildings 18
2.1 The Building Act 1984 18
2.2 The Building Regulations 18
2.3 Approved Documents 19
2.3.1 What about the rest of the United Kingdom? 19
2.4 Electrical safety 20
2.4.1 What is the aim of Approved Document P? 22
2.4.2 Who is responsible for electrical safety? 23
2.4.3 What are the statutory requirements? 23
2.4.4 What types of building does Approved
Document P cover? 25
2.4.5 What is a competent firm? 25
2.4.6 What is a competent person responsible for? 26
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2.4.7 Who is entitled to self-certify an installation? 26
2.4.8 What are the consequences of not obtaining approval? 26
2.4.9 When do I have to inform the local authority
Building Control Body? 27
2.5 What inspections and tests will have to be completed
and recorded? 30
2.5.1 What should be included in the records of
the installation? 30
2.5.2 Where can I get more information about the
requirements of Part P? 30
2.6 The requirement 32
2.6.1 Meeting the requirement 35
2.6.2 Where can I get more information about the
requirements for Electrical Safety? 60
3 Mandatory requirements 61
3.1 What are the mandatory requirements? 63
3.1.1 Personal protection 63
3.1.2 Protection of property 64
3.1.3 Domestic buildings 64
3.1.4 Extensions, material alterations and material
changes of use 66
3.1.5 Electricity distributors’ responsibilities 66
3.2 Design considerations 67
3.2.1 Equipment categories 69
3.2.2 External influences 70
3.3 Electrical installations 78
3.3.1 Electrical installation work 79
3.3.2 Number of circuits 79
3.3.3 Final circuits 79
3.3.4 Domestic cable installation 79
3.3.5 Alarm systems 80
3.3.6 Lighting 83
3.3.7 Electrical connections 84
3.3.8 Power-operated doors 84
3.3.9 Proximity to other electrical services 85
3.3.10 Telephone points and TV sockets 86
3.3.11 Verification 86
3.4 Isolation and switching 87
3.4.1 Isolation 88
3.4.2 Switching 90
3.5 Wiring systems 94
3.6 Earthing 95
3.6.1 Requirements from the Building Regulations 96
3.6.2 Protective multiple earthing 96
3.6.3 Earth electrodes 97
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3.6.4 Earthing conductors 97
3.6.5 Equipotential and supplementary bonding
conductors 97
3.7 Protective measures 98
3.7.1 Protection against direct contact 102
3.7.2 Protection against indirect contact 104
3.7.3 Protection against overcurrent 109
3.7.4 Protection against overvoltage 111
3.7.5 Protection against undervoltage 112
3.7.6 Residual current devices 112
3.8 Equipment 114
3.8.1 Compliance with standards 115
3.8.2 Operational conditions and external
influences 115
3.8.3 Equipment compatibility 116
3.8.4 Heating equipment 116
3.8.5 Portable equipment 117
3.8.6 Rotating machines and motors 117
3.9 Components and accessories 119
3.9.1 Cable couplers 119
3.9.2 Ceiling roses 119
3.9.3 Circuit breakers 119
3.9.4 Control gear 120
3.9.5 Fuses 120
3.9.6 Lampholders 120
3.9.7 Lighting points 121
3.9.8 Luminaries 121
3.9.9 Thermostats 121
3.10 Sockets 122
3.10.1 Socket outlets 122
3.10.2 Wall-mounted socket outlets 123
3.11 Cables 124
3.11.1 Fixtures and connections 125
3.11.2 Heating cables 125
3.11.3 Single-core cables 126
3.11.4 Multicore cables 126
3.11.5 Telecommunication cables 126
3.11.6 UG cable 126
3.12 Conductors 127
3.12.1 Connection methods 127
3.12.2 General 127
3.12.3 Identification of conductors 128
3.12.4 Earthing conductors 129
3.12.5 Live conductors 129
3.12.6 Live supply conductors 130
3.12.7 Neutral conductors 130
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3.12.8 Overhead conductors 130
3.12.9 PEN conductors 130
3.12.10 Phase conductors 131
3.12.11 Protective conductors 131
3.12.12 Supplementary bonding conductors 132
3.13 Power supplies 133
3.13.1 Source supplies 133
3.13.2 Generating sets 135
3.13.3 Transformers 135
3.13.4 Autotransformers and step-up transformers 136
3.14 Circuits 136
3.14.1 Circuit breakers 136
3.14.2 Circuit protective conductors 136
3.14.3 Electric surface heating systems 137
3.14.4 Lighting circuits 137
3.14.5 Separated circuits 137
3.15 Test and inspection 137
3.15.1 Inspections 138
3.15.2 Tests 139
3.16 Special installations and locations 139
3.16.1 Agricultural and horticultural premises 139
3.16.2 Caravans and motor caravans 140
3.16.3 Caravan parks 140
3.16.4 Construction site installations 141
3.16.5 Lecture/conference facilities 141
4 Earthing 142
4.1 What is earth? 142
4.2 What is meant by ‘earthing’ and how is it used? 143
4.3 Advantages of earthing 146
4.4 What types of earthing system are there? 146
4.4.1 System classification 147
4.4.2 TN system 148
4.4.3 TN-C system 149
4.4.4 TN-S system 150
4.4.5 TN-C-S system 150
4.4.6 TT system 152
4.4.7 IT system 153
4.4.8 Requirements 154
4.5 Earthing arrangements 160
4.5.1 General 161
4.5.2 Earth electrodes 161
4.5.3 Earth fault loop impendence 163
4.5.4 Earthing conductors 163
4.5.5 Main earthing terminals 165
4.5.6 Earthing points 166
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4.6 Safety protection 167
4.6.1 Earthing arrangements for protective purposes 168
4.6.2 Earthing arrangements for protective and
functional purposes 168
4.7 Protection against direct contact 169
4.7.1 Protection by insulation of live parts 170
4.7.2 Protection by barriers or enclosures 170
4.7.3 Protection by obstacles 171
4.7.4 Protection by placing out of reach 171
4.7.5 RCDs 172
4.8 Protection against indirect contact 176
4.8.1 Protection by Earthed Equipotential Bonding
and Automatic Disconnection of Supplies
(EEBADS) 177
4.8.2 Protection by Class II equipment or equivalent
insulation 178
4.8.3 Protection by non-conducting location 179
4.8.4 Protection by earth-free local equipotential
bonding 180
4.8.5 Protection by electrical separation 181
4.9 Protection against both direct and indirect contact 183
4.9.1 Protection by SELV 183
4.9.2 Limitation of discharge of energy 186
4.10 Protection against fault current 186
4.11 Protection against overvoltage 187
4.12 Additional requirements 189
4.13 Protective bonding conductors 189
4.13.1 Main equipotential bonding conductors 191
4.13.2 Supplementary bonding conductors 193
4.14 Protection against impact and vibration 195
4.15 Protective conductors 196
4.15.1 Preservation of electrical continuity of
protective conductors 197
4.15.2 Accessibility of connections 198
4.15.3 Identification of conductors by colour 198
4.15.4 Identification of conductors by letters and/or
numbers 200
4.15.5 Warning notice – earthing and bonding
connections 201
4.16 Protective equipment (devices and switches) 202
4.17 Accessories and current-using devices 202
4.17.1 Plugs and socket outlets 202
4.17.2 Lampholders 203
4.17.3 Electrode water heaters and boilers 203
4.17.4 Water heaters having immersed and
uninsulated heating elements 204
