atest draft of BS 7671 Wiring Regs April 2018

801 Pages·2017·28.58 MB·English

PRIVATE CIRCULATION
JPEL/64_18_0077
For information
Requirements for Electrical Installations
IET Wiring Regulations Eighteenth Edition

N
O C
I O
T
P
C
Y
U
R
D I
G
O
H
R
T
P

E ©
R

T
R
h
O J
e
E P I
S E
U E T

L L
A /
CI 6 N
R O
E 4 T

M I F
M n O
f R
O

C o C
r O
R
M
O
m
F M
a
T t E
O i R
N C
o
n IA
L

U
T o
E S
I n E
e l O
h y
R
T

R
©
E
P
T
R
H
O
G
D
I
R U
Y
C
P
T
O
I
C O
N

© DO NOT COPY
Publication Information | 30
Publication Information
Published by the Institution of Engineering and Technology, London, United Kingdom in agreement with BSI.
The Institution of Engineering and Technology is registered as a Charity in England & Wales (no. 211014) and
Scotland (no. SC038698).

N
O C
O
I
T
P
C
Y
U
The Institution of Engineering and Technology is the institution formed in 2006 by the joining together of the IEE R
D I
(the Institution of Electrical Engineers) and the IIE (the Institution of Incorporated Engineers). The new institution G
O
is the inheritor of the IEE brand and all its products and services, such as this one, which we hope you will find H
R
P useful. T

E ©
R

T
R
h
O J
e
E P I
S E
U British Standards InstitutioEn is the independent national body responsible for preparing British Standards. It T

L presents the UK view on standLards in Europe and at the international level. It is incorporated by Royal Charter.
CIA © 2008, 2011, 2013, 2015, 2018 th/e6 Institution of Engineering and Technology and BSI N
R This British Standard was published under the joint authority of the IET and of the Standards Policy and Strategy O
E 4 T
Committee on 1 JanuaryJuly 20185.
M I F
M This publication is copyright under the Berne nConvention and the Universal Copyright Convention. All rights O
O reserved. Apart from any fair dealing for the purpfoses of research or private study, or criticism or review, as R

C permitted under the Copyright, Designs and Patentso Act 1988 this publication may be reproduced, stored or C
transmitted, in any form or by any means, only with ther prior permission in writing of the publishers, or in the O
R
M
O case of reprographic reproduction in accordance with the terms of licences issued by the Copyright Licensing
m
F Agency. Enquiries concerning reproduction outside those terms should be sent to the publishers at The Institution of M
a
T Engineering and Technology, Michael Faraday House, Six Hills Wtay, Stevenage, SG1 2AY, United Kingdom E
O i R
N While the publisher and contributors believe that the information and guidance given in this work is correct, all C
o
parties must rely upon their own skill and judgement when making use onf it. The publisher and contributors do not IA
assume any liability to anyone for any loss or damage caused by any error or omission in the work, whether such L

error or omission is the result of negligence or any other cause. Any and all such liability is disclaimed. U
T o
E S
I The UK participation in its preparation was entrusted to Joint Technical Committene JPEL/64 Electrical Installations. E
e A list of organizations represented on this committee can be obtained on request to itsl secretary. O
h y
R
T This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its

R
© correct application. Compliance with a British Standard cannot confer immunity from legal obligations.
E
P
T The IET is taking the issues found with dangerous counterfeits of its titles very seriously. The hologram on the
R
H
inside cover of this book provides an additional measure to help our customers identify counterfeit versions. For O
G
more information on counterfeits, the hologram and how to identify genuine IET publications, visit www.theiet.org/ D
I
R counterfeit-regs U
Y
C
P
It is the constant aim of the IET and BSI to improve the quality of our products and services. We should be grateful T
O
if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary, G D IO
C
Cronshaw {[email protected]}, The IET, Six Hills Way, Stevenage, SG1 2AY, United Kingdom. N

IET Standards & Compliance staff
as at June 2018December 2014
JPEL/64 Joint IET/BSI Technical Committee G D Cronshaw CEng FIET
Electrical Installations I M Reeve BTech(Hons) DMS CEng MIET
© DO NOT COPY
Publication Information | 31
JPEL/64/A Verification R J Townsend CMS MIETEur Ing Leon Markwell
CEng MIET
JPEL/64/B Thermal Effects P R L Cook CEng FIEEEur Ing Leon Markwell
CEng MIET
JPEL/64/C Shock Protection S G Devine MIET
JPEL/64/D External Influences M Coles BEng(Hons) MIET
Associate secretary to all subcommittees G Gundry MIET

N
O ISBN 978-1-84919-769-4978-1-78561-170-4 (paperback) C
O
TI ISBN 978-1-84919-770-0978-1-78561-171-1 (electronic)
P
C
Y
U Typeset in the UK by the Institution of Engineering and Technology, Stevenage
R
D I
Printed in the UK by Polestar Wheatons, ExeterTo be confirmed G
O
H
R Proofread by PE Donnachie BSc CEng FIET and Gary Gundry MIET
T
P

E ©
R

T
R
h
O J
e
E P I
S E
U E T

L L
A /
CI 6 N
R O
E 4 T

M I F
M n O
f R
O

C o C
r O
R
M
O
m
F M
a
T t E
O i R
N C
o
n IA
L

U
T o
E S
I n E
e l O
h y
R
T

R
©
E
P
T
R
H
O
G
D
I
R U
Y
C
P
T
O
I
O
C
N

© DO NOT COPY
| Contents | 2
CONTENTS
N 28
O 29 C
I Publication Information 30 O
T
C Contents 32 P
Y
U Foreword 35
R
D Introduction to BS 7671:2018 36 I
G
O Introduction to BS 7671:2008 (2015) 40
H
R Introduction to the first amendment 41
T
P Introduction to the second amendment 42
E ©
Introduction to the third amendment, 2015 43
R
Editions 46 T
R
O JJoint IET/BSI Technical Committee JPEL/64 CONSTITUTION 48 h
e
SE PNProetfea cbey the Health and Safety Executive 5520 IE
U NoteEs on the plan of the 18th Edition 53 T

PART 1 SCOPE, OBJECT AND FUNDAMENTAL PRINCIPLES 54
L L
A 11 CHAPTER /SCOPE 54
CI 110.1 GENERAL 6 54 N
R 110.2 EXCLUSIONS FROM SCOPE 55 O
E 111 Not used 4 55 T
M 112 Not used I 55 F
M 113 EQUIPMENT n 55 O
f R
O 114 RELATIONSHIP WITH STATUTORY REGULATIONS 55
C 115 INSTALLATIONS IN PREMoISES SUBJECT TO LICENSING 56 C
r O
R 12 CHAPTER OBJECT AND EFFECTS 57 M
O
120 GENERAL m 57
F M
a 57
T 13 CHAPTER FUNDAMENTAL PRINCIPLEtS 58 E
O i R
N 131 PROTECTION FOR SAFETY 58 C
o
113311..12 GPreonteecratilon against electric shock n 5588 IAL

131.2.1 Basic protection 58 U
T o
E 131.2.2 Fault protection 58 S
e I 131.3 Protection against thermal effects nl 58 E O
h 131.4 Protection against overcurrent y 59
R
T 131.5 Protection against fault current 59

R
© 131.6 Protection against voltage disturbances and measures against electromagnetic
E
disturbances 59 P
T
H 131.7 Protection against power supply interruption 59 R
O
G 59
D
I 132 DESIGN 59
R U
Y 132.1 General 59
C
P 132.2 Characteristics of available supply or supplies 60 T
O
132.3 Nature of demand 60 IO
C
132.4 Electrical supply systems for safety services or standby electrical supply N
systems 60
132.5 Environmental conditions 60
132.6 Cross-sectional area of conductors 60
132.7 Type of wiring and method of installation 61
132.8 Protective equipment 61
132.9 Emergency control 61
132.10 Disconnecting devices 61
© DO NOT COPY
| Contents | 3
132.11 Prevention of mutual detrimental influence 61
132.12 Accessibility of electrical equipment 61
132.13 Documentation for the electrical installation 61
132.14 Protective devices and switches 62
132.15 Isolation and switching 62
132.16 Additions and alterations to an installation 62
133 SELECTION OF ELECTRICAL EQUIPMENT 62
133.1 General 62
133.2 Characteristics 62
133.2.1 Voltage 62
N
133.2.2 Current 62
O C
133.2.3 Frequency 63 O
I
T
133.2.4 Power 63 P
C
Y
U 133.3 Conditions of installation 63
R
D 133.4 Prevention of harmful effects 63 I
G
O 133.5 New materials and inventions 63
H
R 134 ERECTION AND INITIAL VERIFICATION OF ELECTRICAL INSTALLATIONS 63
T
P
134.1 Erection 63
E ©
R 134.2 Initial verification 64

R 135 PERIODIC INSPECTION AND TESTING 64 T
h
O JPART 2 65
e
E DPEFINITIONS 65 I
S SYMBOLS USED IN THE STANDARD 82 E
U ABBEREVIATIONS USED IN THE STANDARD 86 T

L PART 3 LASSESSMENT OF GENERAL CHARACTERISTICS 88
CIA 33001 CASHSAEPSTSEMRE/N6T OF GENERAL CHARACTERISTICS 8888 N
R O
E 31 CHAPTER PUR4POSES, SUPPLIES AND STRUCTURE 88 T

M 311 MAXIMUM DEMANDI AND DIVERSITY 88 F
M 312 CONDUCTOR ARRANnGEMENT AND SYSTEM EARTHING 88 O
312.1 General f 88 R
O
C 312.1.1 Current-carrying conductorso in AC circuits 88 C
312.1.2 Current-carrying conductors inr DC circuits 89 O
R
O 312.2 Types of system earthing 90 M
m
F 312.2.1 TN systems 90 M
T 312.2.1.1 Single-source systems at 90 E
O 312.2.2 TT system i 91 R
N 312.2.2.1 Single-source system o 91 C
312.3 Not used n 92 IA
312.4 IT, multiple source, DC and other systems 92 L

U
T 313 SUPPLIES o 92
E S
I 313.1 General n 92 E
e 313.2 Supplies for safety services and standby systems l 92 O
h y
314 DIVISION OF INSTALLATION 93 R
T
32 CHAPTER CLASSIFICATION OF EXTERNAL INFLUENCES 94 R
©
33 CHAPTER COMPATIBILITY 95 E
P
T 331 COMPATIBILITY OF CHARACTERISTICS 95
R
H
332 ELECTROMAGNETIC COMPATIBILITY 95 O
G
34 CHAPTER MAINTAINABILITY 96 D
I
R 341 GENERAL 96 U
Y
35 CHAPTER SAFETY SERVICES 97 C
P
T
O 351 GENERAL 97
I
C 352 CLASSIFICATION 97 O
N
36 CHAPTER CONTINUITY OF SERVICE 98

361 GENERAL 98
PART 4 PROTECTION FOR SAFETY 99
41 CHAPTER PROTECTION AGAINST ELECTRIC SHOCK 99
410 INTRODUCTION 99
410.1 Scope 99
410.2 Not used 99
© DO NOT COPY
| Contents | 4
410.3 General requirements 99
411 PROTECTIVE MEASURE: AUTOMATIC DISCONNECTION OF SUPPLY 100
411.1 General 100
411.2 Requirements for basic protection 101
411.3 Requirements for fault protection 101
411.3.1 Protective earthing and protective equipotential bonding 101
411.3.1.1 Protective earthing 101
411.3.1.2 Protective equipotential bonding 101
411.3.2 Automatic disconnection in case of a fault 101
411.3.3 Additional requirements for socket-outlets and for the supply of mobile
N
equipment for use outdoors 103
O C
411.3.4 Additional requirements for circuits with luminaires 103 O
I
T
411.4 TN system 103 P
C
Y
U 411.5 TT system 108
R
D 411.6 IT system 109 I
G
O 411.7 Functional extra-low voltage (FELV) 112
H
R 411.7.1 General 112
T
P
411.7.2 Requirements for basic protection 113
E ©
R 411.7.3 Requirements for fault protection 113

R 411.7.4 Sources 113 T
h
O 411.7.5 JPlugs, socket-outlets, LSCs, DCLs and cable couplers 113
e
E 411.8 RPeduced low voltage systems 113 I
S 411.8.1 General 113 E
U 411.8.2 ReqEuirements for basic protection 113 T

L 411.8.3 RequireLments for fault protection 113
A /
CI 441111..88..45 SRoeuqrucieresment6s for circuits 111155 N
R O
E 412 PROTECTIVE M4EASURE: DOUBLE OR REINFORCED INSULATION 115 T

M 412.1 General I 115 F
M 412.2 Requirements for basinc protection and fault protection 116 O
412.2.1 Electrical equipment f 116 R
O

C 412.2.2 Enclosures o 116 C
412.2.3 Installation r 117 O
R
M
O 412.2.4 Wiring systems 117
m
F 413 PROTECTIVE MEASURE: ELECTRICAL SEPARATION 117 M
a
T 413.1 General t 117 E
O 413.2 Requirements for basic protection i 117 R
N C
413.3 Requirements for fault protection o 118
414 PROTECTIVE MEASURE: EXTRA-LOW VOLTnAGE PROVIDED BY SELV OR IA
PELV 118 L
U
T 414.1 General o 118
E S
I 414.2 Requirements for basic protection and fault protectionn 118 E
e 414.3 Sources for SELV and PELV l 119 O
h y
414.4 Requirements for SELV and PELV circuits 119 R
T
415 ADDITIONAL PROTECTION 120 R
©
415.1 Additional protection: RCDs 120 E
P
T 415.2 Additional protection: supplementary protective equipotential bonding 120
R
H
416 PROVISIONS FOR BASIC PROTECTION 121 O
G
416.1 Basic insulation of live parts 121 D
I
R 416.2 Barriers or enclosures 121 U
Y
P 417 OBSTACLES AND PLACING OUT OF REACH 122 C
T
O 417.1 Application 122
I
O
C 417.2 Obstacles 122
N
417.3 Placing out of reach 122

418 PROTECTIVE MEASURES FOR APPLICATION ONLY WHERE THE
INSTALLATION IS CONTROLLED OR UNDER THE SUPERVISION OF
SKILLED OR INSTRUCTED PERSONS 123
418.1 Non-conducting location 123
418.2 Protection by earth-free local equipotential bonding 124
© DO NOT COPY
| Contents | 5
418.3 Electrical separation for the supply to more than one item of current-using
equipment 124
419 PROVISIONS WHERE AUTOMATIC DISCONNECTION ACCORDING TO
REGULATION 411.3.2 IS NOT FEASIBLE 125
42 CHAPTER PROTECTION AGAINST THERMAL EFFECTS 126
420.1 Scope 126
126
126
421 PROTECTION AGAINST FIRE CAUSED BY ELECTRICAL EQUIPMENT 126
421.1 General requirements 126
N
422 PRECAUTIONS WHERE PARTICULAR RISKS OF FIRE EXIST 127
O C
422.1 General 127 O
I
T
422.2 Conditions for evacuation in an emergency 128 P
C
Y
U 422.3 Locations with risks of fire due to the nature of processed or stored materials 129
R
D 422.4 Combustible constructional materials 131 I
G
O 422.5 Fire propagating structures 132
H
R 422.6 Selection and erection of installations in locations of national, commercial,
T
P
industrial or public significance 132
E ©
R 423 PROTECTION AGAINST BURNS 133

R 424 PROTECTION AGAINST OVERHEATING 133 T
h
O 424.1 JForced air heating systems, appliances producing hot water or steam, and
e
E Pspace heating appliances 133 I
S 43 CHAPTER PROTECTION AGAINST OVERCURRENT 134 E
U 430 INTREODUCTION 134 T

L 430.1 Scope L 134
A /
CI 443300..23 NGoetn eursael drequ6irement 113344 N
R O
E 431 PROTECTION A4CCORDING TO THE NATURE OF THE CIRCUITS AND THE T

M DISTRIBUTION SIYSTEM 134 F
M 431.1 Protection of line condnuctors 134 O
431.2 Protection of the neutral cfonductor 134 R
O

C 431.2.1 TN or TT system o 135 C
431.2.2 IT system r 135 O
R
M
O 431.2.3 Harmonic currents 135
m
F 431.3 Disconnection and reconnection of the neutral conductor 135 M
a
T 432 NATURE OF PROTECTIVE DEVICES t 135 E
O 432.1 Protection against both overload current aind fault current 135 R
N C
432.2 Protection against overload current only o 135
432.3 Protection against fault current only n 136 IA
432.4 Characteristics of protective devices 136 L
U
T 433 PROTECTION AGAINST OVERLOAD CURRENTo 136
E S
I 433.1 Co-ordination between conductor and overload protectnive device 136 E
e 433.2 Position of devices for protection against overload l 137 O
h y
433.3 Omission of devices for protection against overload 137 R
T
433.3.1 General 137 R
©
433.3.2 Position or omission of devices for protection against overload in IT systems 137 E
P
T 433.3.3 Omission of devices for protection against overload for safety reasons 137
R
H
433.4 Overload protection of conductors in parallel 138 O
G
433.4.1 Equal current sharing between parallel conductors 138 D
I
R 433.4.2 Unequal current sharing between parallel conductors 138 U
Y
P 434 PROTECTION AGAINST FAULT CURRENT 138 C
T
O 434.1 Determination of prospective fault current 138
I
O
C 434.2 Position of devices for protection against fault current 138
N
434.3 Omission of devices for protection against fault current 139

434.4 Fault current protection of conductors in parallel 139
434.5 Characteristics of a fault current protective device 139
435 CO-ORDINATION OF OVERLOAD CURRENT AND FAULT CURRENT
PROTECTION 141
435.1 Protection afforded by one device 141
435.2 Protection afforded by separate devices 141
© DO NOT COPY
| Contents | 6
436 LIMITATION OF OVERCURRENT BY THE CHARACTERISTICS OF THE
SUPPLY 141
44 CHAPTER PROTECTION AGAINST VOLTAGE DISTURBANCES AND
ELECTROMAGNETIC DISTURBANCES 142
440 INTRODUCTION 142
440.1 Scope 142
440.2 General 142
441 NOT USED 142
442 PROTECTION OF LOW VOLTAGE INSTALLATIONS AGAINST TEMPORARY
OVERVOLTAGES DUE TO EARTH FAULTS IN THE HIGH VOLTAGE
N
SYSTEM AND DUE TO FAULTS IN THE LOW VOLTAGE SYSTEM 142
O C
442.1 Scope and object 142 O
I
T
442.1.1 General 142 P
C
Y
U 442.1.2 Symbols 143
R
D 442.2 Overvoltages in low voltage (LV) systems during a high voltage (HV) earth fault143 I
G
O 442.2.1 Power frequency fault voltage 145
H
R 442.2.2 Magnitude and duration of power frequency stress voltages 145
T
P
442.2.3 Requirements for calculation of limits 146
E ©
R 442.3 Power frequency stress voltage in the event of loss of the neutral conductor in

R a TN or TT system 146 T
h
O 442.4 JPower frequency stress voltage in the event of an earth fault in an IT system
e
E Pwith distributed neutral 146 I
S 442.5 Power frequency stress voltage in the event of short-circuit between a line E
U cEonductor and the neutral conductor 146 T

L 443 PROTECLTION AGAINST TRANSIENT OVERVOLTAGES OF ATMOSPHERIC
A /
CI 443.1 ScoOpRe IGanINd oO6bRje DctUE TO SWITCHING 114466 N
R O
E 4 147 T

M 443.2 Not used I 149 F
M 443.3 Not used n 149 O
443.4 Overvoltage control f 149 R
O

C 443.5 Risk assessment method o 150 C
443.6 Classification of rated impulse rvoltages (overvoltage categories) 152 O
R
M
O 443.6.1 Purpose of classification of rated impulse voltages (overvoltage categories) 152
m
F 443.6.2 Rated impulse voltages of equipment and overvoltage categories 152 M
a
T A443 Annex (informative) Examples of calculatted risk level CRL for the use of SPDs 153 E
O A443.1 Example 1 - Building in rural environmenti 153 R
N C
A443.2 Example 2 - Building in rural environment soupplied by HV 154
A443.3 Example 3 - Building in urban environment supnplied by overhead lines 154 IA
A443.4 Example 4 - Building in urban environment supplie d by underground cables 155 L
U
T B443 Annex (informative) Guidance on overvoltage controol by SPDs applied to
E S
I overhead lines n 155 E
e 444 MEASURES AGAINST ELECTROMAGNETIC DISTURBAlNCES 156 O
h y
444.1 Scope 156 R
T
444.2 Not used 156 R
©
444.3 Not used 156 E
P
T 444.4 Electromagnetic disturbances 156
R
H
444.4.1 Sources of electromagnetic disturbances 156 O
G
444.4.2 Measures to reduce EMI 157 D
I
R 444.4.3 TN system 157 U
Y
P 444.4.4 TT system 159 C
T
O 444.4.5 Not used 161
I
O
C 444.4.6 Multiple-source TN or TT power supplies 161
N
444.4.7 Transfer of supply 162

444.4.8 Not used 162
444.4.9 Separate buildings 162
444.4.10 Inside buildings 162
444.5 Earthing and equipotential bonding 162
444.5.1 Interconnection of earth electrodes 162
444.5.1.1 Within a single building 162
© DO NOT COPY
| Contents | 7
444.5.1.2 Between buildings 162
444.5.2 Equipotential bonding networks 162
444.5.3 Sizing and installation of copper bonding ring network conductors 163
444.5.3.1 Parts to be connected to the equipotential bonding network 163
444.5.4 Not used 163
444.5.5 Not used 163
444.5.6 Not used 163
444.5.7 Earthing arrangements and equipotential bonding of information technology
installations for functional purposes 163
444.5.7.1 Earthing busbar 163
N
444.5.7.2 Cross-sectional area of the earthing busbar 163
O C
444.6 Segregation of circuits 164 O
I
T
444.6.1 General 164 P
C
Y
U 444.6.2 Equipment 164
R
D A444 Annex (Informative) Measures against electromagnetic disturbances 164 I
G
O A444.1 Structures for the network of bonding conductors and earthing conductors 164
H
R A444.1.1 Protective conductors in a star network 164
T
P
A444.1.2 Multiple meshed bonding star network 164
E ©
R A444.1.3 Common meshed bonding star network 165

R A444.1.4 Protective conductors connected to a bonding ring conductor 165 T
h
O A444.2 JEquipotential bonding networks in buildings with several floors 166
e
E A444.3 IPnstallations containing a high density of interconnected equipment 167 I
S A444.4 Design guidelines for segregation of circuits 167 E
U A444.5 ConEditions for zero segregation 169 T

L 445 PROTECLTION AGAINST UNDERVOLTAGE 170
A /
CI 44465.1 GCHenAePrTalE rRe qIuS6iOreLmAeTnIOtsN AND SWITCHING 117700 N
R O
E 460 SCOPE 4 170 T

M 461 GENERAL I 170 F
M 462 ISOLATION n 170 O
463 FUNCTIONAL SWITCHINfG (CONTROL) 171 R
O

C 463.1 General o 171 C
463.2 Auxiliary circuits r 172 O
R
M
O 463.3 Motor control 172
m
F 464 SWITCHING OFF FOR MECHANICAL MAINTENANCE 172 M
a
T 465 EMERGENCY SWITCHING OFF t 172 E
O PART 5 SELECTION AND ERECTION OF iEQUIPMENT 174 R
N C
51 CHAPTER COMMON RULES o 174
510 INTRODUCTION n 174 IA
510.1 General 174 L
U
T 510.2 Not used o 174
E S
I 511 COMPLIANCE WITH STANDARDS n 174 E
e 512 OPERATIONAL CONDITIONS AND EXTERNAL INFLUElNCES 174 O
h y
512.1 Operational conditions 174 R
T
512.1.1 Voltage 174 R
©
512.1.2 Current 174 E
P
T 512.1.3 Frequency 175
R
H
512.1.4 Power 175 O
G
512.1.5 Compatibility 175 D
I
R 512.1.6 Impulse withstand voltage 175 U
Y
512.2 External influences 175 C
P
T
O 513 ACCESSIBILITY 176
I
O
C 514 IDENTIFICATION AND NOTICES 176
N
514.1 General 176

514.2 Not used 176
514.3 Identification of conductors 176
176
514.4 Identification of conductors by colour 176
514.4.1 Neutral or midpoint conductor 176
514.4.2 Protective conductor 176
© DO NOT COPY
| Contents | 8
514.4.3 PEN conductor 177
514.4.4 Other conductors 177
514.4.6 Bare conductors 177
514.5 Identification of conductors by letters and/or numbers 177
514.5.2 Protective conductor 177
514.5.3 Alphanumeric 177
514.5.4 Numeric 177
514.6 Omission of identification by colour or marking 177
514.7 Not used 179
514.8 Identification of a protective device 179
N
514.9 Diagrams and documentation 179
O C
514.10 Warning notice: voltage 179 O
I
T
514.11 Warning notice: isolation 179 P
C
Y
U 514.12 Notices: periodic inspection and testing 179
R
D 514.13 Warning notices: earthing and bonding connections 180 I
G
O 514.14 Warning notice: non-standard colours 181
H
R 514.15 Warning notice: alternative supplies 181
T
P
514.16 Notice: high protective conductor current 181
E ©
R 515 PREVENTION OF MUTUAL DETRIMENTAL INFLUENCE 181

R 515.1 Prevention of mutual detrimental influence 181 T
h
O J 182
e
E 52 CPHAPTER SELECTION AND ERECTION OF WIRING SYSTEMS 183 I
S 520 INTRODUCTION 183 E
U 520.1 ScopEe 183 T

L 520.2 Not useLd 183
A /
CI 552200..34 NGoetn eursaeld 6 118833 N
R O
E 521 TYPES OF WIR4ING SYSTEM 183 T

M 521.4 Busbar trunking systIems and powertrack systems 183 F
M 521.5 AC circuits: electromangnetic effects 183 O
521.5.1 Ferromagnetic enclosuresf: electromagnetic effects 183 R
O

C 521.5.201 Electromechanical stresseso 184 C
521.6 Conduit, ducting, trunking, trayr and ladder systems 184 O
R
M
O 521.7 Multicore cables: two or more circuits 184
m
F 521.8 Circuit arrangements 184 M
a
T 521.9 Use of flexible cables t 184 E
O 521.10 Installation of cables i 184 R
N C
o 185
522 SELECTION AND ERECTION OF WIRING SYnSTEMS IN RELATION TO IA
EXTERNAL INFLUENCES 185 L
U
T 522.1 Ambient temperature (AA) o 185
E S
I 522.2 External heat sources n 185 E
e 522.3 Presence of water (AD) or high humidity (AB) l 186 O
h y
522.4 Presence of solid foreign bodies (AE) 186 R
T
522.5 Presence of corrosive or polluting substances (AF) 186 R
©
522.6 Impact (AG) 186 E
P
T 522.7 Vibration (AH) 188
R
H
522.8 Other mechanical stresses (AJ) 188 O
G
522.9 Presence of flora and/or mould growth (AK) 189 D
I
R 522.10 Presence of fauna (AL) 189 U
Y
P 522.11 Solar radiation (AN) and ultraviolet radiation 189 C
T
O 522.12 Seismic effects (AP) 189
I
O
C 522.13 Movement of air (AR) 189
N
522.14 Nature of processed or stored materials (BE) 189

522.15 Building design (CB) 189
523 CURRENT-CARRYING CAPACITIES OF CABLES 190
523.5 Groups containing more than one circuit 190
523.6 Number of loaded conductors 191
523.7 Conductors in parallel 191
523.8 Variation of installation conditions along a route 191
© DO NOT COPY