wiring systems (including the
Table of Contents
About the authors xvii
Preface to the Fourth Edition xix
Acknowledgements xxi
Notation xxiii
1 Plan and terminology of BS 7671:2008 and supporting publications 1
1.1 Plan of BS 7671:2008 1
1.2 Terminology of BS 7671:2008 5
1.3 Supporting publications 6
2 Electricity, the law, standards and codes of practice 7
2.1 General 7
2.2 Electricity: the hazards 7
2.3 The law 12
2.4 Standards and codes of practice 13
3 Scope, object and fundamental principles 17
3.1 General 17
3.2 Scope 17
3.3 Object and effects 20
3.4 Fundamental principles 21
4 Assessment of general characteristics 29
4.1 General 29
4.2 Loading, maximum demand and diversity 29
4.3 Arrangement of live conductors and type of earthing 35
4.4 Nature of supply 40
4.5 Supplies for safety services and standby purposes 44
4.6 Installation circuit arrangements 44
4.7 External influences 45
4.8 Compatibility 45
4.9 Maintainability 46
5 Protection against electric shock 47
5.1 General 47
5.2 Provisions for basic protection 51
5.3 Protective measure: automatic disconnection of supply 53
5.4 Protective measure: double or reinforced insulation 75
5.5 Protective measure: electrical separation 77
5.6 Protective measure: extra-low voltage provided by SELV or PELV 78
5.7 Additional protection 81
5.8 Obstacles and placing out of reach 82
5.9 Protective measures for application only where the installation is controlled or under the supervision of skilled or instructed persons 83
6 Protection against thermal effects 89
6.1 General 89
6.2 Fire caused by electrical equipment 91
6.3 Precautions where particular risks of danger of fire exist 95
6.4 Burns 100
7 Protection against overcurrent, undervoltage and overvoltage 101
7.1 General 101
7.2 Nature of protective devices 102
7.3 Protection against overload 104
7.4 Protection against fault current 110
7.5 Determination of prospective fault current 112
7.6 Characteristics of protective devices 128
7.7 Overcurrent protection of conductors in parallel 131
7.8 Coordination of overload and fault current protection 134
7.9 Protection according to the nature of circuits and distribution systems 135
7.10 Protection against undervoltage 136
7.11 Protection against overvoltage 137
8 Isolation and switching 139
8.1 General 139
8.2 Main switch 143
8.3 Isolation 145
8.4 Switching off for mechanical maintenance 151
8.5 Emergency switching and other forms of switching for safety 153
8.6 Emergency stopping 157
8.7 Functional switching 158
8.8 Identification and notices 160
9 Equipment selection: common rules 161
9.1 General 161
9.2 Compliance with standards 161
9.3 Operational conditions, external influences and accessibility 162
9.4 Identification and notices 164
9.5 Mutual detrimental influences 176
9.6 Compatibility 178
9.7 Operation and maintenance manual 179
10 Wiring systems 181
10.1 Wiring systems 181
10.2 External influences 185
10.3 Proximity to other services: general 199
10.4 Methods of installation of cables 205
10.5 Resistances of copper conductors 217
10.6 Electrical connections 218
10.7 Cable supports and cable management systems 224
10.8 Minimizing the risk of fire 230
10.9 Electromagnetic and electromechanical effects 231
10.10 Conduit and trunking cable capacities 233
10.11 Maintainability 238
11 Switchgear, protective devices and other equipment 241
11.1 Switchgear and protective devices: general 241
11.2 Switchgear and controlgear 241
11.3 Selection of devices for overload and fault current protection: general 243
11.4 Overcurrent protective devices 247
11.5 Residual current devices 261
11.6 Identification of overcurrent protective devices 271
11.7 Discrimination 272
11.8 Other equipment 279
12 Protective conductors, earthing and equipotential bonding 289
12.1 Protective conductors 289
12.2 Earthing 307
12.3 Earthing requirements for the installation of equipment having high protective conductor currents 314
12.4 Protective bonding 318
13 Specialized installations 325
13.1 General 325
13.2 Emergency lighting 325
13.3 Fire detection and alarm systems 326
13.4 Petrol filling stations and liquid petroleum gas stations 331
13.5 Installations in dusty environments 331
13.6 Installations in underground and multistorey car parks, etc 332
13.7 Installations in multi-occupancy blocks of flats 332
13.8 Installations in ‘Section 20 buildings’ 332
13.9 Installations in churches 334
13.10 Installations in thatched properties 334
13.11 Extra-low voltage lighting 335
13.12 Outdoor lighting installations, highway power supplies and street furniture 338
13.13 Security lighting 341
13.14 Welding equipment 342
13.15 Entertainers’ equipment 342
13.16 Generator sets 342
14 Safety services 347
14.1 Safety services: general 347
14.2 Common sources 348
14.3 Parallel and nonparallel sources 350
14.4 Circuit and equipment requirements 351
14.5 Protection against overcurrent and electric shock under fault conditions 351
15 The smaller installation 353
15.1 Scope 353
15.2 The IEE On-Site Guide and the NICEIC Domestic Electrical Installation Guide 353
15.3 User’s requirements 353
15.4 Wiring systems 355
15.5 Electricity distributor’s requirements 355
15.6 Assessment of supply characteristics 355
15.7 ‘Meter tails’ 356
15.8 System earthing arrangements 357
15.9 Main protective bonding 360
15.10 Minimum cross-sectional area of earthing and main protective bonding conductors 360
15.11 Supplementary bonding 362
15.12 Devices for protection against overcurrent and for fault protection 362
15.13 Devices for isolation and switching 363
15.14 Final circuit design 363
15.15 Remote buildings 384
15.16 Minimum number of socket-outlets in domestic premises 385
15.17 Modifications to existing installations 385
15.18 Inspection, testing, verification and certification of the smaller installation 387
16 Special installations and locations 389
16.1 General 389
16.2 Locations containing a bath or shower 389
16.3 Swimming pools and other basins 398
16.4 Rooms and cabins containing sauna heaters 407
16.5 Construction-site installations 407
16.6 Agricultural and horticultural premises 413
16.7 Conducting locations with restricted movement 421
16.8 Electrical installations in caravan/camping parks and similar locations 422
16.9 Marinas and similar locations 429
16.10 Exhibition shows and stands 430
16.11 Solar photovoltaic power supply systems 435
16.12 Mobile or transportable units 440
16.13 Electrical installations in caravans and motor caravans 445
16.14 Temporary electrical installations for structures, amusement devices and booths at fairgrounds, amusement parks and circuses 451
16.15 Floor and ceiling heating systems 452
17 Inspection, testing, certification and reporting 459
17.1 Inspection, testing, certification and reporting: general 459
17.2 Test instruments 459
17.3 Safety in electrical testing 462
17.4 Test methods 463
17.5 Initial verification 483
17.6 Periodic inspection and testing 512
17.7 Alterations and additions 534
17.8 Inspection, testing and certification of specialized installations 535
Appendix Standards to which reference has been made 537
Bibliography 545
Index of figures 547
Index of tables 551
Index of regulation numbers 557
Subject index 579
