BS 7671:2018+A2:2022 Electrical Installations PDF

BRITISH STANDARD BS 7671:2018 incorporating...

BRITISH STANDARD BS 7671:2018 incorporating Corrigendum 2018 Amendment 1:2020 Corrigendum 2020 Amendment 2:2022 Requirements for Electrical Installations IET Wiring Regulations Eighteenth Edition I- T bsi. c::::::J The Institution of c::::::J Engineering and Technology @The Institution of Engineering and Technology and BS!. NO COPYING IN ANY FORM WlTHOlJTWRITTEN PERMISSION.  Publication Information Published by the Institution of Engineering and Technology, London, United Kingdom in agreement with BS!. The Institution of Engineering and Technology is registered as a Charity in England & Wales (no. 211014) and Scotland (no. SC038698). The Institution of Engineering and Technology is the institution formed in 2006 by the joining l:T together of the IEE (the Institution of Electrical Engineers) and the !IE (the Institution of Incorporated Engineers). bsi. British Standards Institution is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. © 2008, 2011, 2013, 2015, 2018, 2020, 2022 the Institution of Engineering and Technology and BS!. This British Standard (BS 7671:2018+A2:2022) was published under the joint authority of the !ET and of the Standards Policy and Strategy Committee on 28 March 2022. This publication is copyright under the Berne Convention and the Universal Copyright Convention. All rights reserved. Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988 this publication may be reproduced, stored or transmitted, in any form or by any means, only with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms of licences issued by the Copyright Licensing Agency. Enquiries concerning reproduction outside those terms should be sent to the publishers at The Institution of Engineering and Technology, Michael Faraday House, Six Hills Way, Stevenage, SG I 2AY, United Kingdom While the publisher and contributors believe that the info1mation and guidance given in this work is correct, all pai1ies must rely upon their own skill and judgement when making use ofit. The publisher and contributors do not assume any liability to anyone for any loss or damage caused by any error or omission in the work, whether such euor or omission is the result of negligence or any other cause. Any and all such liability is disclaimed. The UK participation in its preparation was entrusted to Joint Technical Committee JPEL/64 Electrical Installations. A list of organizations represented on this committee can be obtained on request to its Committee Manager. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. The !ET is taking the issues found with dangerous counterfeits of its titles very seriously. The hologram on the inside cover of this book provides an additional measure to help our customers identify counterfeit versions. For more information on counterfeits, the hologram and how to identify genuine IET publications, visit https ://electrical. theiet.org/bs-7 671 /fake-awareness/ It is the constant aim of the !ET and BS! to improve the quality of our products and services. We should be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Committee Manager, G D Cronshaw {[email protected]}, The !ET, Six Hills Way, Stevenage, SG I 2AY, United Kingdom. IET Technical Regulations staff as at August 2021 JPEL/64 Joint IET/8S1 Technical Committee G D Cronshaw CEng FIET Electrical Installations JPEL/A/64 Verification M Peace CEng MIET MCIBSE JPEL/B/64 Thetmal Effects Eur Ing L D Markwell MSc BSc(Hons) CEng MIET MCIBSE LCGI.IPEL/C/64 Shock Protection S G Devine !Eng MIET JPEL/D/64 External Influences M Coles BEng(Hons) MIET Associate Committee Manager RH Giddings !Eng MIET ACIBSE ISBN 978-1-83953-218-4 (paperback) ISBN 978-1-83953-220-7 (vitalsource) Proofread by M Doughton !Eng MJET LCGI and G Gundry MIET Typeset in the UK by the Institution of Engineering and Technology, Stevenage Printed and bound in the UK by CPI Group (UK) Ltd, Croydon, CR40 4YY 2  CONTENTS Introduction to BS 7671:2018 4 Introduction to Amendment 1:2020 7 !ntroduction to Amendment 2:2022 8 PART 1 SCOPE, OBJECT AND FUNDAMENTAL PRINCIPLES 19 CHAPTER 11 SCOPE 20 CHAPTER 12 OBJECT AND EFFECTS 22 CHAPTER 13 FUNDAMENTAL PRINCIPLES 22 PART2 DEFINITIONS 29 PART3 ASSESSMENT OF GENERAL CHARACTERISTICS 50 CHAPTER 30 ASSESSMENT OF GENERAL CHARACTERISTICS 51 CHAPTER 31 PURPOSES, SUPPLIES AND STRUCTURE 51 CHAPTER 32 CLASSIFICATION OF EXTERNAL INFLUENCES 56 CHAPTER 33 COMPATIBILITY 57 CHAPTER 34 MAINTAINABILITY 57 CHAPTER 35 SAFETY SERVICES 58 CHAPTER 36 CONTINUITY OF SERVICE 58 PART4 PROTECTION FOR SAFETY 59 CHAPTER 41 PROTECTION AGAINST ELECTRIC SHOCK 62 CHAPTER 42 PROTECTION AGAINST THERMAL EFFECTS 84 CHAPTER 43 PROTECTION AGAINST OVERCURRENT 93 CHAPTER 44 PROTECTION AGAINST VOLTAGE DISTURBANCES 102 CHAPTER 45 NOT USED 123 CHAPTER 46 ISOLATION AND SWITCHING 124 PART 5 SELECTION AND ERECTION OF EQUIPMENT 127 CHAPTER 51 COMMON RULES 130 CHAPTER 52 SELECTION AND ERECTION OF WIRING SYSTEMS 139 CHAPTER 53 PROTECTION, ISOLATION, SWITCHING, CONTROL AND MONITORING 154 CHAPTER 54 EARTHING ARRANGEMENTS AND PROTECTIVE CONDUCTORS 197 CHAPTER 55 OTHER EQUIPMENT 208 CHAPTER 56 SAFETY SERVICES 225 PARTS INSPECTION AND TESTING 230 CHAPTER 61 NOT USED 231 CHAPTER 62 NOT USED 231 CHAPTER 63 NOT USED 231 CHAPTER 64 INITIAL VERIFICATION 232 CHAPTER 65 PERIODIC INSPECTION AND TESTING 239 PART? SPECIAL INSTALLATIONS OR LOCATIONS 241 SECTION 700 GENERAL 241 SECTION 701 LOCATIONS CONTAINING A BATH OR SHOWER 242 SECTION 702 SWIMMING POOLS AND OTHER BASINS 247 SECTJON 703 ROOMS AND CABINS CONTAINING SAUNA HEATERS 256 SECT!ON 704 CONSTRUCTION AND DEMOLITION SITE INSTALLATIONS 258 SECTION 705 AGRICULTURAL AND HORTICULTURAL PREMISES 260 SECTION 706 CONDUCTING LOCATIONS WITH RESTRICTED MOVEMENT 265 SECTION 708 ELECTRICAL INSTALLATIONS IN CARAVAN/ CAMPING PARKS AND SIMILAR LOCATIONS 267 SECTION 709 MARINAS AND SIMILAR LOCATIONS 271 SECTION 710 MEDICAL LOCATIONS 276 SECTION 711 EXHIBITIONS, SHOWS AND STANDS 288 SECTION 712 SOLAR PHOTOVOLTAIC (PV) POWER SUPPLY SYSTEMS 291 SECTION 714 OUTDOOR LIGHTING INSTALLATIONS 302 SECTION 715 EXTRA-LOW VOLTAGE LIGHTING INSTALLAT!ONS 304 SECTION 717 MOBILE OR TRANSPORTABLE UNITS 307 SECTION 721 ELECTRICAL INSTALLATIONS IN CARAVANS AND MOTOR CARAVANS 315 SECTION 722 ELECTRIC VEHICLE CHARGING INSTALLATIONS 325 SECTION 729 OPERATING AND MAINTENANCE GANGWAYS 331 SECTION 730 ONSHORE UNITS OF ELECTRICAL SHORE CONNECTIONS FOR INLAND NAVIGATION VESSELS 336 SECTION 740 TEMPORARY ELECTRICAL INSTALLATIONS FOR STRUCTURES, AMUSEMENT DEVICES AND BOOTHS AT FAIRGROUNDS, AMUSEMENT PARKS AND CIRCUSES 341 SECTION 753 HEATING CABLES AND EMBEDDED HEATING SYSTEMS 346 PART 8 FUNCTIONAL REQUIREMENTS 350 CHAPTER 82 PROSUMER'S LOW VOLTAGE ELECTRICAL INSTALLATIONS 352 APPENDICES 384 1 (Normative) BRITISH STANDARDS TO WHICH REFERENCE IS MADE IN BS7671 385 2 (Informative) STATUTORY REGULATIONS AND ASSOC!ATED MEMORANDA 406 3 (Informative) TIME/CURRENT CHARACTERISTICS OF OVERCURRENT PROTECTIVE DEVICES 409 4 (Informative) CURRENT-CARRYING CAPACITY AND VOLTAGE DROP FOR CABLES 421 5 (Informative) CLASSIFICATION OF EXTERNAL INFLUENCES 492 6 (Informative) MODEL FORMS FOR CERTIFICATION AND REPORTING 508 7 Deleted by BS 7671:201B+A2:2022 532 8 {Informative) CURRENT-CARRYING CAPACITY AND VOLTAGE DROP FOR BUSBAR TRUNKING AND POWERTRACK SYSTEMS 533 9 (Informative) DEFINITIONS - MULTIPLE SOURCE, DC AND OTHER SYSTEMS 535 10 (Informative) PROTECTION OF CONDUCTORS IN PARALLEL AGAINST OVERCURRENT 543 11 (Informative) WARNING AND USER INSTRUCTION LABELS 547 12 NOT USED 551 13 (Informative) ESCAPE ROUTES AND FIRE PROTECTION 552 14 (Informative) DETERMINATION OF PROSPECTJVE FAULT CURRENT 554 15 (Informative) RING AND RADIAL F!NAL CIRCUIT ARRANGEMENTS, REGULATION 433.1 555 16 (Informative) DEVICES FOR PROTECTION AGAINST OVERVOLTAGE 557 17 (Informative) ENERGY EFFICIENCY 563 TABLE OF FIGURES 569 TABLE OF TABLES 573 INDEX 576 3  Foreword This British Standard is published under the direction of the British Standards Institution and the Institution of Engineering and Technology (JET). Following a full review, this Standard replaced the I 7th Edition of the IEE Wiring Regulations BS 7671 :2008 as amended. Copyright is held jointly by the JET and BS!. Technical authority for this Standard is vested in the Joint JET/BS! Technical Committee JPEL/64. This Joint Technical Committee, which is responsible for the work previously undertaken by the IEE Wiring Regulations Committee and the BS! Technical Committee PEL/64, meets the constitutional and operational requirements ofbotl1 parent bodies. JPEL/64 has the responsibility for the content ofthis British Standard under the joint authority of the JET and the BS! Standards Board. All references in this text to the JET Wiring Regulations or the Regulation(s), where not otherwise specifically identified, shall be taken to refer to BS 7671:2018 Requirements for Electrical Installations, as amended by Amendment 1 :2020 and Amendment 2:2022. Additions or alterations to regulations owing to the issue of BS 7671:2018:A2:2022 are indicated by a side bar in the margin. Introduction to BS 7671 :2018 BS 7671:2018 Requirements for Electrical Installations was issued on 1st July 2018 and is intended to come into effect on 1st January 2019. Installations designed after 31st December 2018 are to comply with BS 7671 :2018. The Regulations apply to the design, erection and verification of electrical installations, also additions and a1terations to existing installations. Existing installations that have been installed in accordance with earlier editions of the Regulations may not comply with this edition in every respect. This does not necessarily mean that they are unsafe for continued use or require upgrading. A summary of the main changes is given below. NOTE: This is not an exhaustive list. Part 1 Scope, object and fundamental principles Regulation 133.1.3 (Selection of equipment) has been modified and now requires certain usage of equipment to be recorded on the appropriate electrical certification specified in Paii 6. Part 2 Definitions Definitions have been expanded and modified. Chapter 41 Protection against electric shock Section 411 contains a number of significant changes. Some of the main ones are mentioned below. Metallic pipes entering the building having an insulating section at their point of entry need not be connected to the protective equipotential bonding (Regulation 411.3.1.2). The maximum disconnection times stated in Table 41.1 now apply to final circuits rated up to 63 A with one or more socket-outlets and final circuits rated up to 32 A supplying only fixed connected current-using equipment (Regulation 411.3.2.2). Regulation 411.3.3 has been revised and now applies to socket-outlets with a rated current not exceeding 32 A. There is an exception to omit RCD protection where, other than for a dwelling, a documented risk assessment determines that RCD protection is not necessary. A new Regulation 411.3.4 requires that, within domestic (household) premises, additional protection by an RCD with a rated residual operating current not exceeding 30 mA shall be provided for AC final circuits supplying luminaires. Regulation 411.4.3 has an addition that states that no switching or isolating device shall be inserted in a PEN conductor. Regulations 411.4.4 and 411.4.5 have been redrafted. The regulations concerning IT systems (411.6) have been reorganized. Regulations 411.6.3.1 and 411.6.3.2 have been deleted and 411.6.4 redrafted and a new Regulation 411.6.5 inserted. 4 A new Regulation group ( 419) has been inserted where automatic disconnection according to Regulation 411.3.2 is not feasible, such as electronic equipment with limited shortMcircuit current. Chapter 42 Protection against thermal effects Anew Regulation 421.1. 7 has been introduced recommending the installation of arc fault detection devices (AFDDs) to mitigate the risk of fire in AC final circuits of a fixed installation due to the effects of arc fault currents. Regulation 422.2.1 has been redrafted. Reference to conditions BD2, BD3 and BD4 has been deleted. A note has been added stating that cables need to satisfy the requirements of the CPR in respect of their reaction to fire and making reference to Appendix 2, item 17. Requirements have also been included for cables that are supplying safety circuits. Chapter 44 Protection against voltage disturbances and electromagnetic disturbances Section 443, which deals with protection against overvoltages of atmospheric origin or due to switching, has been redrafted. The AQ criteria (conditions of external influence for lightning) for determining if protection against transient overvoltages is needed are no longer included. Instead, protection against transient overvoltages has to be provided where the consequence caused by overvoltage (see Regulation 443.4): (i) could result in serious injury to, or loss of, human life, or (ii) could result in intem1ption of public services/or damage to and cultural heritage, or (iii) could result in interruption of commercial or industrial activity, or (iv) could affect a large number of co-located individuals. For all other cases, a risk assessment has to be perforn1ed in order to determine if protection against transient overvoltage is required. There is an exception not to provide protection for single dwelling units in certain situations. Chapter 46 Isolation and switching A new Chapter 46 has been introduced. This deals with non-automatic local and remote isolation and switching measures for the prevention or removal of dangers associated with electrical installations or electrically powered equipment. Also, switching for the control of circuits or equipment. Where electrically powered equipment is within the scope of BS EN 60204, only the requirements of that standard apply. Chapter 52 Selection and erection of wiring systems Regulation 521.10.202, which gives requirements for the methods of support of wiring systems, has replaced Regulation 521.11.201. This is a significant change. Regulation 521.10.202 requires cables to be adequately suppmted against their premature collapse in the event of a fire and applies throughout the installation, not just in escape routes as previously. Regulation 527.1.3 has also been modified, and a note added stating that cables also need to satisfy the requirements of the CPR in respect of their reaction to fire. Chapter 53 Protection, isolation, switching, control and monitoring This chapter has been completely revised and deals with general requirements for protection, isolation, switching, control and monitoring and with the requirements for selection and erection of the devices provided to fulfil such functions. Section 534 Devices for protection against overvoltage This section focuses mainly on the requirements for the selection and erection of SPDs for protection against transient overvoltages where required by Section 443, the BS EN 62305 series, or as otherwise stated. Section 534 has been completely revised. The most significant technical change refers to the selection requirements for the voltage protection level. Chapter 54 Earthing arrangements and protective conductors Two new regulations (542.2.3 and 542.2.8) have been introduced concerning earth electrodes. Chapter 55 Other equipment Regulation 550.1 introduces a new scope. 5  New Regulation 559.10 refers to ground-recessed luminaires, the selection and erection of which shall take account of the guidance given in Table A.I of BS EN 60598-2-13. Part 6 Inspection and testing Pai1 6 has been completely restmctured, including the regulation numbering to align with the CENELEC standard. Chapters 61, 62 and 63 have been deleted and their content now forms two new Chapters 64 and 65. Section 704 Construction and demolition site installations This section contains a number of small changes, including requirements for external influences (Regulation 704.512.2), and a modification to Regulation 704.410.3.6 to include the non-use of the protective measure of electrical separation. Section 708 Electrical installations in caravan/camping parks and similar locations This section contains a number of changes including requirements for socket-outlets, RCD protection, and operational conditions and external influences. Section 710 Medical locations This section contains a number of small changes including the removal of Table 710, and changes to Regulations 710.415.2.1 to 710.415.2.3 concerning equipotential bonding. In addition, a new Regulation 710.421.1.201 states requirements regarding the installation of AFDDs. Section 715 Extra-low voltage lighting installations This section contains only minor changes including modifications to Regulation 715.524.201. Section 721 Electrical installations in caravans and motor caravans This section contains a number of changes to the requirements concerning electrical separation, RCDs, proximity to non-electrical services and protective bonding conductors. Section 722 Electric vehicle charging installations This section contains significant changes to Regulation 722.411.4.1 concerning the use of a PME supply. The exception concerning reasonably practicable has been deleted. Changes have also been made to requirements for external influences, RCDs, socket-outlets and connectors. Section 730 Onshore units of electrical shore connections for inland navigation vessels This is an entirely new section. Section 730 applies to onshore installations dedicated to the supply of inland navigation vessels for commercial and administrative purposes, berthed in ports and berths. Most, if not all, of the measures used to reduce the risks in marinas apply equally to electrical shore connections for inland navigation vessels. One of the major differences between supplies to vessels in a typical marina and electrical shore connections for inland navigation vessels is the size of the supply needed. Section 753 Heating cables and embedded heating systems This retitled section has been completely revised. The scope of Section 753 has been extended to apply to embedded electric heating systems for surface heating. The requirements also apply to electric heating systems for de-icing, frost prevention cind similar applications, and cover both indoor and outdoor systems. Heating systems for industrial and commercial applications complying with BS EN 60519, BS EN 62395 and BS EN 60079 are not covered. Appendices The following main changes have been made within the appendices: Appendix 1 British Standards to which reference is made in the Regulations has been updated, as necessary. Appendix 3 Time/current characteristics of overcurrent protective devices and RCDs The previous content of Appendix 14 concerning earth fault loop impedance has been moved into Appendix 3. Appendix 6 Model forms for certification and reporting This appendix includes minor changes to the certificates, changes to the inspections (for new installation work only) for domestic and similar premises with up to I 00 A supply, and examples of items requiring inspection for an electrical installation condition report. 6 Appendix 8 Current-carrying capacity and voltage drop for busbar trunking and powertrack systems This appendix includes changes regarding rating factors for current-carrying capacity. Appendix 14 Determination of prospective fault current As stated earlier, the content of Appendix 14 concerning earth fault loop impedance has been moved into Appendix 3. Appendix 14 now contains information on the determination of prospective fault current. Appendix 17 Energy efficiency This is a new appendix that provides recommendations for the design and erection of electrical installations, including installations having local production and storage of energy, for optimizing the overall efficient use of electricity. The recommendations within the scope of this appendix apply for new electiical installations and modification of existing electrical installations. Much of this appendix will not apply to domestic and similar installations. It is intended that this appendix will be developed into Part 8 of BS 7671 in a future amendment. Introduction to Amendment 1 :2020 Amendment 1:2020 to BS 7671:2018 Requirements for Electrical Installations was issued on 1st February 2020 and may be implemented immediately. Electrical installations falling within the scope of Section 722, the erection of which is commenced after 31st July 2020, are to comply with BS 7671 :2018 incorporating Amendment I :2020. Amendment I :2020 amends Section 722 Electric Vehicle Charging Installations. Part 2 Definitions relating to Section 722 have been included. Section 700 General This overarching section explains the need for Paii 7. Section 722 Electric vehicle charging installations, Section 722 amended, based on HD 60364-7-722:2018. Section 722 applies to electric vehicle charging installations. It modifies the general requirements for protection against electric shock, and includes specific requirements with regard to PME systems, socket-outlets and connectors, external influences, isolation and switching and RCD protection. Regulation 722.411.4.1 adds indent (iv) which adds an alternative solution requirement for charging installations. The requirements of this section do not apply to wireless charging, such as inductive charging. Appendix 1 References to British Standards for Section 722 have been included. Index Entries for Section 722 have been included. 7  Introduction to Amendment 2:2022 BS 7671:2018+A2:2022 Requirements for Electrical Jn,tallations was issued on 28th March 2022 and may be implemented immediately. BS 7671:2018+Al:2020 remains current and will be withdrawn on 27th September 2022. The Regulations apply to the design, erection and verification of electrical installations, also additions and alterations to existing installations. Existing installations that have been installed in accordance with earlier editions of the Regulations may not comply with this edition in every respect. This does not necessarily mean that they are unsafe for continued use or require upgrading. Contractual and legal considerations This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. NOTE 1: Completion of an electrical installation designed to the withdra\VD standard can be subject to the contractual agreement between all parties involved. NOTE 2: BSI publishes information on the uses of withdrawn British Standards. A summary of the main changes is given below. NOTE 3: This is not an exhaustive list. Part 1 Scope, Object and Fundamental principles Minor changes have been made including reference to prosumers electrical installations and installing fibre optic cables. Part 2 Definitions Definitions have been expanded and modified. Chapter 41 Protection against electric shock Section 411 contains a number of significant changes. Some of the main changes are mentioned below. Regulation 411.3.1.2 has been redrafted. The regulation now requires that in each consumer's installation within a building extraneous-conductive-parts that are liable to introduce a dangerous potential difference be connected to the main earthing terminal. A note has been added clarifying that where non-metallic pipes, e.g. plastic, enter the building and are then conuected to metallic pipes within the building, the metallic pipes within the building do not normally require protective bonding as they are unlikely to be extraneous-conductive-parts. Reference to insulating sections has been removed. Regulation 411.3.3 has been redrafted and now has three indents. There is still an exception to omit RCD protection where, other than BAI, BA3 or children (BA2, BA3) and mobile equipment (not exceeding 32 A) for use outdoors, a suitably documented risk assessment dete1mines that RCD protection is not necessary. Regulation 411.4.2 now recommends an additional connection to Earth, by means of an earth electrode in accordance with Chapter 54, is made to the main earthing terminal. Chapter 42 Protection against thermal effects Regulation 421.1. 7 has been redrafted. It is now a requirement to protect final circuits supplying socket-outlets with a rated current not exceeding 32 A using arc fault detection devices (AFDD) in Higher Risk Residential Buildings, Houses in Multiple Occupation, Purpose-built student accommodation and Care homes. For all other premises, the regulation recommends AFDDs for single-phase AC final circuits supplying socket-outlets not exceeding 32 A. The use of AFDDs does not obviate the need to apply one or more measures provided in other clauses in this standard. Regulation 422.1 (precautions where particular risks of fire exist) now introduces requirements for the fire safety design of the building(s) to be documented. Also requirements have been added where cables should have an improved fire performance. Regulation 422.2 now introduces separate requirements for escape routes and a new concept of 'protected escape routes'. Reference to conditions BD2, BD3 and BD4 have been deleted. 8 Chapter 44 Protection against voltage disturbances and electromagnetic disturbances Regulation 443.4 for determining if protection against transient overvoltages is needed has been redrafted, Regulation 443.4.1 now requires protection against transient overvoltages to be provided where the consequence caused by the overvoltage could result in: (i) serious injmy to, or loss of, human life (ii) failure of a safety service, as defined in Part 2 (iii) significant financial or data loss. For all other cases, protection against transient overvoltages shall be provided unless the owner of the installation declares it is not required due to any loss or damage being tolerable and they accept the risk of damage to equipment and any consequential loss. Regulation 443.4.2 requires protection against overvoltages to be considered in the case of equipment likely to produce switching overvoltages or disturbances and gives conditions. Regulation 443.5 (Risk assessment method) has been deleted and Annex A443 (examples of calculated risk level CRL for use of SPDs) has also been deleted. Section 514 Identification and notices Section 514 contains a number of significant changes (including illustrations of notices which have been removed and examples are provided in Appendix 11 ). Some of the main changes are mentioned below. Table 51 has been modified slightly to take into account changes of colour identification for DC and abbreviations have been added. Regulation 514.9.1 now contains an exception for domestic (household) premises. Regulation 514.9.2 has been introduced to advise that all diagrams, chaiis, and information or instruction notices comply with the applicable standards specified. Regulation 514.12 (Notices: periodic inspection and testing) now contains an exception for domestic (household) premises in ce1iain situations. Regulation 514.12.2, concerning the RCD notice, has been modified and now contains an exception for domestic (household) premises in certain situations. Regulation 514.14 concerning non-standard colours has been deleted. A new Regulation 514.16.1 has been introduced requiring a label to indicate the presence of SPDs. However, there is an exception for domestic (household) premises or similar. Chapter 53 Protection, isolation, switching, control and monitoring Regulation 531.3.2 indent (ii) highlights the use of RCBOs for individual final circuits in residential premises to minimise unwanted tripping. Regulation 531.3.3 now states that RCD Type AC shall only be used to serve fixed equipment, where it is known that the load current contains no DC components. Chapter 54 Earthing arrangements and protective conductors Modifications have been made to Regulation Group 543.7 conce1ning earthing requirements for the installation of equipment having high protective conductor currents. Regulation 544.1.1 conce1ning main protective bonding conductors has also been revised. Chapter 55 Other equipment 551.7 Additional requirements have been added for installations where the generating set or sets may operate in parallel with other sources including systems for distribution of electricity to the public. 551.7.2 includes additional conditions. 554.4 Heating conductors and cables Regulations 554.4.2, 554.4.3, and 554.4.4 have been deleted. 9  Chapter 64 Initial verification Regulation Group 643.3 has been redrafted. The requirements for testing insulation resistance where equipment is likely to influence the verification test or be damaged has been clarified and reference is made to a 250 V DC test following the connection of equipment. The requirements for RCD testing have been changed and Table 3A (Time/current performance criteria for RCDs) in Appendix 3 has been deleted. Regardless ofRCD Type, an alternating current test at rated residual operating cunent (I"") is used to verify the effectiveness. Section 702 Swimming pools and other basins Regulation, 702.414.3, concerning SELV and PELV, has been introduced. Section 703 Rooms and cabins containing sauna heaters Regulation 703.414.3, concerning SELV and PELV, has been introduced. Section 704 Construction and demolition site installations Regulation 704.511.1 includes changes to plugs and socket-outlet requirements. Changes have also been made to requirements for wiring systems (704.52) and the requirements for devices for isolation have been redrafted (704.537). Section 706 Conducting locations with restricted movement The requirements for protection against electric shock have been completely redrafted. A new Regulation 706.415, requirements for additional protection, has also been introduced. Section 710 Medical locations Changes include requirements concerning socket-outlet circuits in the medical IT systems and minor changes to requirements concerning luminaires and lighting installations. Also, requirements concerning diagrams and documentation have been changed. Requirements for IT systems have also been redrafted. Changes also include requirements for fault protection and requirements for protective equipotential bonding. Section 711 Exhibitions, shows and stands Anew Regulation 711.410.3.101 has been introduced. It sets out the requirements for all final circuits, other than those of safety services, having a rated current not exceeding 32 A supplying socket-outlets or handheld electrical equipment, and all final circuits for lighting to use either automatic disconnection of supply (with additional protection by means of an :,30 mA RCD), SELV or PELV, or electrical separation. Regulation 711.42 concerning protection against thermal effects has been deleted. Requirements for isolation and switching have been redrafted. In addition, the regulations covering luminaires and lighting installations have been redrafted. Section 712 Solar photovoltaic (PV) power supply systems The technical content of this section has been extensively revised and expanded. Requirements of this section now apply to: (i) PV installations not connected to a system for distribution of electricity to the public, (ii) PV installations in parallel with a system for distribution of electricity to the public, (iii) PV installations as an alternative to a system for distribution of electricity to the public. Section 714 Outdoor lighting installations This section includes changes to automatic disconnection of supply and additional protection. Section 717 Mobile or transportable units Regulation 717.411.4 has been expanded to take account of PME. Section 722 Electric vehicle charging installations This section incorporates BS 7671:2018+Al:2020 together with other changes, such as, taking account ofprosumer's electrical installations (722.826.3.201). Indent (i) of Regulation 722.411.4.1 has been deleted, also changes have been made to the notes in particular the one concerning where equipment to be used is not covered by a British or Harmonized Standard. In addition, the Annex to 722 has been redrafted and includes guidance on indent (iii) of Regulation 722.411.4.1. 10 Section 753 Heating cables and embedded heating systems Changes include the addition of new regulations (relocated from Chapter 53) covering impact and the installation of heating cables. Chapter 82 Prosumer's low-voltage electrical installations This is an entirely new chapter. Historically, utility companies have managed the public transmission and distribution network from the point of view of having central production adapted to demand variation. The objective of this chapter is to provide requirements, such thatJ low-voltage electrical installations are compatible with the cunent and future ways to deliver safely the electrical energy to current-using equipment either from the public network or from other local sources. Chapter 82 provides additional requirements, measures and recommendations for design, erection and verification of all types of low voltage electrical installations. This includes local production and/or storage of energy in order to achieve compatibility with existing and future ways to deliver electrical energy to current-using equipment or to the public network by means of local sources. Such electrical installations are designated as Prosumer's Electrical Installations (PEis). Appendices The following main changes have been made within the Appendices: Appendix 3 Table 3A, covering the tripping times of RCDs, has been deleted. Appendix 4 includes minor changes concerning a cable surrounded by thennal insulation. Appendix 6 Model forms for certification and reporting Minor changes have been made to the model forms and guidance for recipients. These include the addition of fields for recording the details of SPDs andAFDDs. The schedule of inspections has been simplified for initial verification. A new example checklist of items requiring inspection during initial verification has been added to Appendix 6 but is not required to be provided with the cetiificate. The single page generic schedule oftest results used for EiC and EICR has been redrafted. There is now a separate page for the schedule of circuit details and a separate page for the schedule of test results. Appendix 7 Deleted by BS 7671:2018+A2:2022 Appendix 11 Warning and user instruction labels This is a new appendix that provides guidance for the types of safety signs, warning signs and instructions required to be applied to electdcal installations. Appendix 13 Escape routes and fire protection The previous content of Appendix 13 concerning methods for measuring the insulation resistance/impedance of floors and walls to Eatih has been removed and replaced by guidance on escape routes and fire protection. The new content of Appendix 13 provides detailed guidance on protected escape routes in order to afford a safe passage through the building to an exit. Appendix 17 Energy efficiency This appendix includes changes to the scope to cover dwellings and reference to the Building Regulations, changes to user decisions, also new design recommendations, new information on determination of meshes, new information on user requirements, new guidance covering impacts on the design of an installation, and new guidance on periodic assessment. 11  Editions The following editions have been published: FIRST EDITION Entitled 'Rules nod Regulations for the Prevention of Fire Risks Arising from Electric Lighting'. Issued in 1882. SECOND EDITION Issued in 1888. THIRD EDIT[ON Entitled 'General Rules recommended for Wiring for the Supply ofElectrical Energy'. Issued in 1897. FOURTH EDITION Issued in 1903. FfFTH EDITION Entitled 'Wiring Rules'. Issued in 1907. SIXTH EDITION Issued in 1911. SEVENTH EDITION Issued in 1916. EIGHTH EDITION Entitled 'Regulations for the Electrical Equipment of Buildings'. Issued in 1924. NINTH EDITJON Issued in 1927. TENTH EDITION Issued in 1934. ELEVENTH EDITION Issued in 1939. Revised, issued in 1943. Reprinted with minor Amendments, 1945. Supplement issued, 1946. Revised Section 8 issued, 1948. TWELFTH EDITION Issued in 1950. Supplement issued, 1954. THIRTEENTH EDITION Issued in 1955. Reprinted 1958, 1961, 1962 and 1964. FOURTEENTH EDITION Issued in 1966. Reprinted incorporating Amendments, 1968. Reprinted incorponiting Amendments, 1969. Supplement on use in metric terms issued, 1969. Amendments issued, 1970. Reprinted in metric units incorporating Amendments, 1970. Reprinted 1972. Reprinted 1973. Amendments issued, 1974. Reprinted inc01porating Amendments, 1974. Amendments issued, 1976. Reprinted incorporating Amendments, 1976. FIFTEENTH EDITION Entitled 'Regulations for Electrical lnstallations'. Issued in 1981. (Red Cover) Amendments issued, I January 1983. Reprinted incorporating Amendments, 1983. (Green Cover) Amendments issued, I May 1984. Reprinted incorporating Amendments, 1984. (Yellow Cover) Amendments issued, 1 January 1985. Amendments issued, l January 1986. Reprinted incorporating Amendments, 1986. (Blue Cover) Amendments issued, 12 June 1987. Reprinted incorporating Amendments, 1987. (Brown Cover) Reprinted with minor corrections, 1988. (Brown Cover) SfXTEENTH EDITION Issued in 1991. (Red Cover) Reprinted with minor corrections, 1992. (Red Cover) Entitled and reprinted as 'Requirements for Electrical Installations BS 7671 :1992'. (Red Cover) Amendment No 1 issued, December 1994. Reprinted incorporating Amendment No 1, 1994. (Green Cover) Amendment No 2 issued, December 1997. Reprinted incorporating Amendment No 2, 1997. (Yellow Cover) Amendment No 3 issued, April 2000. BS 7671 :2001 issued, June 2001. (Blue Cover) Amendment No 1 issued, February 2002. Amendment No 2 issued, March 2004. Reprinted incorporating Amendments 1 and 2, 2004. (Brown Cover) SEVENTEENTH EDITION BS 7671 :2008 issued, January 2008. (Red Cover) Reprinted incorporating Amendment No 1, 2011. (Green Cover) Amendment 2 issued, Aug 2013. Reprinted incorporating Amendments 2 and 3, 2015. (Yellow Cover) EIGHTEENTH EDITION BS 7671 :2018 issued, July 2018. (Blue Cover) Amendment 1 issued, February 2020 (electronic) Amendment 2 issued, March 2022. (Brown Cover) 12  Joint IET/BSI Technical Committee JPEL/64 CONSTITUTION as at August 2021 Em Ing J T Bradley BSc CEng FIET (Chairman) Eur Ing P Sayer CEng FIET GCGI (Deputy Chairman) for JET Em Ing G Kenyon BEng(Hons) CEng MIET Tech!OSH (Chair - JPEL/D/64) HR Lovegrove !Eng FIET G G Willard DipEE CEng FIET JP (Deputy Chair- JPEL/D/64) G Digilio !Eng FIEE ACIBSE MSLL G Gundry MIET J Peckham !Eng FIET LCGI S Robinson CEng FIET FIMechE FCIBSE FSLL and K Hoare MSc CEng MCIBSE MIET (ACE -Association for Consultancy and Engineering) SA MacConnacher BSc CEng MIEE MlnstR (Association of Manufacturers of Domestic Appliances) A Greer (Association of Manufacturers of Power Generating Systems) M Froggatt (British Approvals Service for Cables) Dr J Hodge CChem CSci FRSC (British Cables Association) Eur Ing J Wright BEng CEng MIET (BEAMA Installation Ltd) P Norris MIET (BEAMA Ltd) G Brown BEng (Hons) !Eng MIET (BEAMA Ltd) C Smith (BEIS - Department for Business, Energy and Industrial Strategy) J Devaney (BS!) D Moore (BS!) A Samad Khan MEng (Hons) CEng MIET MIEEE (Individual Capacity; UK Expert - CLC/TC64/WG 4; liaison GEL 81, PEL 37/1) T Benstead CEng MSc BEd MCIBSE MIET (Chair- JPEL/B/64) J Elliott BSc(Hons) PGCert CEng MIET (Certsure LLP; Chair - JPEL/A/64) N Bird !Eng MIET (Chair - JPEL/C/64) D Cowburn BSc(Hons) (Competent Persons Forum) Dr ACM Sung BSc(Hons) MSc PhD CEng FIET FCIBSE SrMIEEE MEI MHKIE(Ir) (CIBSE and EI) K Siriwardhana BScEng (Hons), MSc, MBA, CEng, FIET, SMIEEE, MCIGRE (CIGRE-UK) S Ogborn FIET MSET LCGI (City & Guilds of London Institute) D Irwin (DC Users Forum) B Duun CEng BEng(Hons) (MoD) K Sparrow !Eng MIET CertEd (EAL) S Khan BSc (Hons) MIET (ECA) G Parker BEng (Hons) !Eng MIET MCIBSE MEI LCGI (ECA) 13  R Cairney !Eng MIET (Electrical Contractors' Association of Scotland t/a SELECT) D Fonester !Eng MIET MlnstLM (Electrical Contractors' Association of Scotland t/a SELECT) M Allen BEng(Hons) CEng MIET (Electrical Safety First) D Spillett MIET MIOSH MIIRSM (Energy Networks Association and Liaison - GEL/8) R Wardak MIET (The GAMBICA Association Ltd) M Hadley (The GAMBICAAssociation Ltd) S Mason BSc CEng FIET (Health and Safety Executive) I Andrews (Heating Ventilating and Air Conditioning Manufacturers Association) Eur Ing PHarris BEng(Hons) FIHEEM MIEE MCIBSE (Institute of Healthcare Engineering and Estate Management) P Davies (lntertek-Group Pie) G CT Pritchard BTech(Hons) CEng FILP MIET Tech!OSH (Institution of Lighting Professionals and HEA) Eur Ing L D Markwell MSc BSc (Hons) CEng MIET MCIBSE LCGJ (Liaison-FSH/12) M Cotterell (Liaison - GEL/82) T Oldershaw (Liaison - TCT/7) Eur Ing M Mullins BA CEng FIET (Liaison - JPEL/18) M Peace CEng MIET MCIBSE (Liaison - PEL/69) M Coles BEng(Hons) MIET (Liaison - GEL/82) LC Barling (The Lighting Industry Association) F Bertie MIET (NAPIT; Deputy Chair-JPEL/A/64) I Storrar BSc (Hons) CEng FCIBSE FIHEEM MIET (NHS Scotland) J Eade BEng(Hons) CEng MIET AMIMechE (Professional Lighting and Sound Association) G Brindle BSc(Hons) CEng MIET CMILT (Railway Industry Association) M Kenyon MIET (Safety Assessment Federation - SAFed) Dr T Nicklin (Society of Motor Manufacturers and Traders Ltd) N Lowe (Society of Motor Manufacturers and Traders Ltd) CJ Tanswell CEng MIEE (Society for Public Architecture, Construction, Engineering and SUiveying - SPACES) P Grinnall (SPATA Swimming Pool and Allied Trades Association Ltd) Committee Manager G D Cronshaw CEng FIET 14  Preface BS 7671 :2018, Requirements for Electrical Installations, takes account of the technical substance of agreements reached at CENELEC level in Harmonized Documents (HD). Where no CENELEC HD exists, !EC level documents are taken into account. In particular, the technical intent of the following CENELEC HDs and !EC docmnents is included: HD orIEC Year Document reference BS 7671 HD 60364-1 2008 (2017) Fundamental principles, assessment of general... , definitions Pa11s 1,2,3 HD 60364-4-41 2007 (2017) Protection against electric shock Chapter 41 HD 60364-4-42 2011 (2015) Protection against thermal effects Chapter 42 HD 60364-4-43 2010 Protection against overcurrent Chapter 43 !EC 60364-4-44 2007 (2015) Protection against voltage disturbances and electromngnetic disturbances Section 440 HD 60364-4-442 2012 Protection of low-voltage installations against temporary overvoltages Section 442 due to earth faults in the high-voltage system and due to faults in the low voltage system HD 60364-4-443 2016 Protection against transient overvoltages of atmospheric origin or due Section 443 to switching HD 60364-4-444 2010 (2012) Protection against voltage and electromagnetic disturbances Section 444 HD 60364-4-46 2016 (2017) Isolation and switching Chapter 46 HD 60364-5-51 2009 (2017) Selection and erection of electrical equipment - Common rules Chapter 51 HD 60364-5-52 2011 (2017) Selection and erection of electrical equipment - Wiring systems Chapter 52 HD 60364-5-53 2015 (2017) Selection and erection of electrical equipment - Switchgear and controlgear Chapter 53 HD 60364-5-534 2016 Devices for protection against transient overvoltages Section 534 HD 60364-5-54 2011 (2017) Earthing arrangements and protective conductors Chapter 54 HD 60364-5-551 2010 (2016) Low-voltage generating sets Section 551 HD 60364-5-557 2013 (2016) Auxiliary circuits Section 557 HD 60364-5-559 2012 (2017) Luminaires and lighting installations Section 559 HD 60364-6-56 2018 Safety services Chapter 56 HD 60364-6 2016 (2017) Verification Part 6 HD 60364-7-701 2007 (2017) Locations containing a bath or shower Section 701 HD 60364-7-702 2010 Swimming pools and fountains Section 702 HD 60364-7-703 2005 Rooms and cabins containing sauna heaters Section 703 HD 60364-7-704 2018 Construction and demolition site installations Section 704 HD 60364-7-705 2007 (2017) Agricultural and hotiicultural premises Section 705 HD 60364-7-706 2007 (2020) Conducting locations with restricted movement Section 706 HD 60364-7-708 2017 Caravan parks, camping parks and similar locations Section 708 HD 60364-7-709 2009 (2019) Marinas and similar locations Section 709 HD 60364-7-710 2012 (2013) Medical locations Section 710 HD 60364-7-711 2019 Exhibitions, shows and stands Section 711 HD 60364-7-712 2016 Photovoltaic (PV) systems Section 712 HD 60364-7-714 2012 External lighting installations Section 714 HD 60364-7-715 2012 (2017) Extra-low-voltage lighting installations Section 715 HD 60364-7-717 2010 (2014) Mobile or transportable units Section 717 !EC 60364-7-721 2019 Electrical installations in caravans and motor caravans Section 721 HD 60364-7-722 2018 Supplies for electric vehicles Section 722 HD 60364-7-729 2009 (2017) Operating or maintenance gangways Section 729 HD 60364-7-730 2015 Onshore units of electrical shore connections for inland navigation Section 730 vessels HD 60364-7-740 2006 (2017) Temporary electrical installations for structures, amusement devices Section 740 and booths at fairgrounds, amusement parks and circuses HD 60364-7-753 2014 (2014) Heating cables and embedded heating systems Section 753 HD 60364-8-1 2019 (2019) Functional aspects - energy efficiency Appx 17 HD 60364-8-2 2018 Prosumer's low-voltage electrical installations Chapter 82 15  The dates in brackets refer to the year of issue of amendments to the documents. Where the above documents contain UK special national conditions, those conditions have been incorporated within BS 7671. IfBS 7671 is applied in other countries the above documents should be consulted to confirm the status of a particular regulation. BS 7671 will continue to be amended from time to time to take account of the publication of new or amended CENELEC and IEC standards. The opportunity has been taken to revise regulations that experience has shown require clarification or to allow for new technology and methods. Reference is made throughout BS 7671 to publications of the British Standards Institution, both specifications and codes of practice. Appendix I lists these publications and gives their full titles whereas throughout BS 7671 they are referred to only by their numbers. Where reference is made in BS 7671 to a British Standard which takes account of a CENELEC Harmonization Document, European Norm (EN) or IEC standard, it is understood that the reference also relates to any European national standard similarly derived from the CENELEC standard, although account needs to be taken of any national exemptions. 16  Note by the Health and Safety Executive The Health and Safety Executive (HSE) welcomes the publication of BS 7671 :2018, Requirements for Electrical Installations, JET Wiring Regulations 18th Edition and its updating with the second amendment, published in 2022. BS 7671 and the !ET/IEE Wiring Regulations have been extensively referred to in HSE guidance over the years. Installations which conform to the standards laid down in BS 7671:2018+A2:2022 are regarded by HSE as likely to achieve conformity with the relevant parts of the Electricity at Work Regulations 1989. Installations to which BS 7671 is relevant may have been designed and installed in accordance with an earlier edition, now superseded but then current. That, in itself, would not mean that the installation would fail to comply with the Electricity at Work Regulations, 1989. Notes on the plan of the 18th Edition This Edition is based on the plan agreed internationally for the anangement of safety rules for electrical installations. The regulation numbering follows the pattern and conesponding references of !EC HD 60364 series. The numbering does not, therefore, necessarily follow sequentially. The numbering system used in Part 7 is explained in Section 700. In the numbering system used, the first digit signifies a Part, the second digit a Chapter, the third digit a Section and the subsequent digits the Regulation number. For example, Section number 413 is made up as follows: PART 4 - PROTECTION FOR SAFETY Chapter 41 (first chapter of Part 4) - PROTECTION AGAINST ELECTRIC SHOCK Section 413 (third section of Chapter 41) - PROTECTIVE MEASURE: ELECTRICAL SEPARATION Part 1 sets out the scope, object and fundamental principles. Part 2 defines the sense in which certain terms arc used throughout the Regulations, and provides a list of symbols used and a list of abbreviations used in the Standard. The subjects of the subsequent parts are as indicated below: Part Subject Part 3 Identification of the characteristics of the installation that will need to be taken into account in choosing and applying the requirements of the subsequent Parts. These characteristics may vary from one patt of an installation to another and should be assessed for each location to be served by the installation. Part 4 Description of the measures that are available for the protection of persons, livestock and property, and against the hazards that may arise from the use of electricity. Part 5 Precautions to be taken in the selection and erection of the equipment of the installation. Part 6 Inspection and testing. Part 7 Special installations or locations - particular requirements. Part 8 Functional requirements The sequence of the plan should be followed in considering the application of any particular requirement of the Regulations. The general index provides a ready reference to particular regulations by subject, but in applying any one regulation the requirements of related regulations should be borne in mind. Cross-references are provided, and the index is atTanged to facilitate this. In many cases, a group of associated regulations is covered by a side heading which is identified by a two-part number, e.g. 544.2. Throughout the Regulations where reference is made to such a two-patt number, that reference is to be taken to include all the individual regulation numbers which are covered by that side heading m1d include that two-pati number. The Regulations use the IEC decimal point numbering system to make it easier to embody future changes and additions resulting from ongoing international standards work within !EC and CENELEC. In order to identify and accommodate future IEC changes some regulations cany either a 100 or 200 number where 100 numbers represent CENELEC Harmonization Document reference numbers and 200 numbers represent UK-only regulations. Some regulations have not been 1updated1 to indicate 100 and 200 numbers; that will only be done when those regulations require a significant rewrite. 17  Guidance on the language used within BS 7671 To help all users of BS 7671, the following definitions apply specifically to the language used within this Standard: Guidance. Element containing informative text. Informative annex. Annex that contains additional recommendations, guidance or statements intended to assist the understanding or use of the document. Informative element: Preliminary informative element. Element that identifies the document, introduces its content and explains its background, its development and its relationship with other documents. Supplementary informative element. Element that provides additional information intended to assist the understanding or use of the document. Normative annex. Annex that contains requirements or procedural instTuctions additional to those in the body of the document Normative element. Element that describes the scope of the document or sets out requirements. Note. Element containing informative text. Requirement. Expression in the content of a document conveying criteria to be fulfilled if compliance with the document is to be claimed and from which no deviation is permitted. Recommendation. Expression in the content of a document conveying that among several possibilities one is recommended as particularly suitable, without mentioning or excluding others. The following table describes verbal forms which may be used to express normative and informative elements: Verbal forms used in BS 7671 Implication Verbal form Typical context Requirement Shall Normative element Recommendation Should Informative element Permission May Informative element Possibility mid capability Can Informative element Possibility Might Informative element Description Is Informative element The content of this table is based on Rules for the structure and drafting of UK standards, second edition published April 2017, published by BS! Standards Ltd. 18  PART1 SCOPE, OBJECT AND FUNDAMENTAL PRINCIPLES CONTENTS CHAPTER 11 SCOPE 110.1 GENERAL 110.2 EXCLUSIONS FROM SCOPE 111 NOT USED 112 NOT USED 113 EQUIPMENT 114 RELATIONSHIP WITH STATUTORY REGULATIONS 115 INSTALLATIONS IN PREMISES SUBJECT TO LICENSING CHAPTER12 OBJECT AND EFFECTS 120 GENERAL CHAPTER13 FUNDAMENTAL PRINCIPLES 131 PROTECTION FOR SAFETY 131.1 General 131.2 Protection against electric shock 131.3 Protection against thermal effects 131.4 Protection against overcurrent 131.5 Protection against fault current 131.6 Protection against voltage disturbances and measures against electromagnetic disturbances 131.7 Protection against power supply interruption 132 DESIGN 132.1 General 132.2 Characteristics of available supply or supplies 132.3 Nature of demand 132.4 Electrical supply systems for safety services or standby electrical supply systems 132.5 Environmental conditions 132.6 Cross-sectional area of conductors 132.7 Type of wiring and method of installation 132.8 Protective equipment 132.9 Emergency control 132.10 Disconnecting devices 132.11 Prevention of mutual detrimental influence 132.12 Accessibility of electrical equipment 132.13 Documentation for the electrical installation 132.14 Protective devices and switches 132.15 Isolation and switching 132.16 Additions and alterations to an installation 133 SELECTION OF ELECTRICAL EQUIPMENT 133.1 General 133.2 Characteristics 133.3 Conditions of installation 133.4 Prevention of harmful effects 133.5 New materials and inventions 134 ERECTION AND INITIAL VERIFICATION OF ELECTRICAL INSTALLATIONS 134.1 Erection 134.2 Initial verification 135 PERIODIC INSPECTION AND TESTING 19  PART1 SCOPE, OBJECT AND FUNDAMENTAL PRINCIPLES CHAPTER 11 SCOPE 110.1 GENERAL 110.1.1 The Regulations apply to the design, erection and verification of electrical installations such as those of: (i) residential premises (ii) commercial premises (iii) public premises (iv) industrial premises (v) prefabricated buildings (vi) low voltage generating sets (vii) highway equipment and street furniture (viii) locations containing a bath or shower (ix) swimming pools and other basins (x) rooms and cabins containing sauna heaters (xi) constn1ction and demolition sites (xii) agricultural and horticultural premises (xiii) conducting locations with restricted movement (xiv) caravan/ camping parks and similar locations (xv) marinas and similar locations (xvi) medical locations (xvii) exhibitions, shows and stands (xviii) solar photovoltaic (PV) power supply systems (xix) outdoor lighting (xx) extra-low voltage lighting (xxi) mobile or transportable units (xxii) caravans and motor caravans (xxiii) electric vehicle charging (xxiv) operating and maintenance gangways (xxv) temporruy installations for stluctures, amusement devices and booths at fairgrounds, amusement parks and circuses including professional stage and broadcast applications (xxvi) floor and ceiling heating systems (xxvii) onshore units of electrical shore connections for inland navigation vessels. NOTE: 'Premises' covers the land and all facilities including buildings belonging to it. 110.1.2 The Regulations include requirements for: (i) circuits supplied at nominal voltages up to and including I 000 V AC or 1500 V DC. For AC, the preferred frequencies which are taken into account in BS 7671 are 50 Hz, 60 Hz and 400 Hz. The use of other frequencies for special purposes is not excluded (ii) circuits, other than the internal wiring of equipment, operating at voltages exceeding 1000 V and derived from an installation having a voltage not exceeding I 000 V AC, e.g. discharge lighting, electrostatic precipitators (iii) wiring systems and cables not specifically covered by the standards for appliances (iv) prosumer's low voltage electrical installations (PEI) including those located external to buildings (v) all consumer installations external to buildings (vi) fixed wiring for information and communication technology, signalling, control and the like, including installation and support of fibre optic cables (excluding internal wiring of equipment) (vii) additions and alterations to installations and also parts of the existing installation affected by an addition or alteration. 20 110.1.3 The Regulations are intended to be applied to electrical installations generally but, in certain cases, they may need to be supplemented by the requirements or recommendations of other British or Harmonized Standards or by the requirements of the person orde1ing the work. Such cases include the following: (i) Electric signs and high voltage luminous discharge tube installations - BS 559 and BS EN 50107 (ii) Emergency lighting - BS 5266 and BS EN 1838 (iii) Explosive atmospheres - BS EN 60079 series (iv) Electrical apparatus for use in the presence of combustible dust - BS EN 50281 and BS EN 60079 (v) Fire detection and fire alarm systems for buildings - BS 5839 (vi) Telecommunications systems - BS 6701 (vii) Electric surface heating systems - BS EN 60335-2-96 (viii) Electrical installations for open-cast mines and quanies - BS 6907 (ix) Tempora1y electrical systems for events, entertainment and related purposes - BS 7909 (x) Life safety and firefighting applications - BS 8519 and BS 9999. 110.2 EXCLUSIONS FROM SCOPE The Regulations do not apply to the following installations: (i) Systems for the distribution of electricity to the public other than prosumer's installations covered by Chapter 82 (ii) Railway traction equipment, rolling stock and signalling equipment (iii) Equipment of motor vehicles, except those to which the requirements of the Regulations concerning caravans or mobile units are applicable (iv) Equipment on board ships covered by BS 8450, BS EN 60092-507, BS EN ISO 13297 or BS EN ISO 10133 (v) Equipment of mobile and fixed offshore installations (vi) Equipment of aircraft (vii) Those aspects of mines specifically covered by Statutmy Regulations (viii) Radio interference suppression equipment, except so far as it affects safety of the electrical installation (ix) Lightning protection systems for buildings and structures covered by BS EN 62305 (x) Those aspects of lift installations covered by relevant parts of BS 5655 and BS EN 81 and those aspects of escalator or moving walk installations covered by relevant pa1ts of BS 5656 and BS EN 115 (xi) Electrical equipment of machines covered by BS EN 60204 (xii) Electric fences covered by BS EN 60335-2-76 (xiii) The DC side of cathodic protection systems complying with the relevant part(s) of BS EN ISO 12696, BS EN 12954, BS EN ISO 13174, BS EN 13636 and BS EN 14505. 111 NOT USED 112 NOT USED 113 EQUIPMENT 113.1 The Regulations apply to items of electrical equipment only so far as selection and application of the equipment in the installation are concerned. The Regulations do not deal with requirements for the construction of assemblies of electrical equipment, which are required to comply with appropriate standards. 114 RELATIONSHIP WITH STATUTORY REGULATIONS 114.1 The Regulations are non-statutory. They may, however, be used in a court oflaw in evidence to claim compliance with a statutmy requirement. The relevant statutory provisions are listed in Appendix 2 and include Acts of Parliament and Regulations made thereunder. In some cases statutmy Regulations may be accompanied by Codes of Practice approved under Section 16 of the Health and Safety at Work etc. Act 1974. The legal status of these Codes is explained in Section 17 of the 1974 Act. For a supply given in accordance with the Electricity Safety, Quality and Continuity Regulations, it shall be deemed that the connection with Earth of the neutral of the supply is permanent. Outside England, Scotland, Wales and Northern Ireland, confirmation shall be sought from the distributor that the supply conforms to requirements corresponding to those of the Electricity Safety, Quality and Continuity Regulations (ESQCR), in this respect. Where the ESQCR does not apply, equipment for isolation and switching shall be selected accordingly as specified in Chapters 46 and 53. 21  115 INSTALLATIONS IN PREMISES SUBJECT TO LICENSING 115.1 For installations in premises over which a licensing or other authority exercises a statutory control, the requirements of that authority shall be ascertained and complied with in the design and execution of the installation. CHAPTER 12 OBJECT AND EFFECTS 120 GENERAL 120.1 BS 7671 contains requirements for the design, erection and verification of electrical installations so as to provide for safety and proper functioning for the intended use. 120.2 Chapter 13 states the fundamental principles. It does not include detailed technical requirements, which may be subject to modification because of technical developments. 120.3 BS 7671 sets out technical requirements to enable electrical installations to conform with the fundamental principles of Chapter 13, as follows: Part 3 Assessment of general characteristics Part 4 Protection for safety Part 5 Selection and erection of equipment Part 6 Inspection and testing Part 7 Special installations or locations Part 8 Functional requirements. Any intended departure from these Parts requires special consideration by the designer of the installation and shall be recorded on the appropriate electrical certification specified in Part 6. The resulting degree of safety of the installation shall be not less than that obtained by compliance with the Regulations. CHAPTER 13 FUNDAMENTAL PRINCIPLES 131 PROTECTION FOR SAFETY 131.1 General The requirements of this chapter are intended to provide for the safety of persons, livestock and property against dangers and damage which may arise in the reasonable use of electrical installations. The requirements to provide for the safety of livestock are applicable in locations intended for them. In electrical installations, risk of injury may result from: (i) shock currents (ii) excessive temperatures likely to cause burns, fires and other injurious effects (iii) ignition of a potentially explosive atmosphere (iv) undervo1tages, overvoltages and electromagnetic disturbances likely to cause or result in injury or damage (v) mechanical movement of electrically actuated equipment, in so far as such injury is intended to be prevented by electrical emergency switching or by electrical switching for mechanical maintenance of non-electrical parts of such equipment (vi) power supply interruptions and/or interruption of safety services (vii) arcing or burning, likely to cause blinding effects, excessive pressure and/or toxic gases. 131.2 Protection against electric shock 131.2.1 Basic protection Persons and livestock shall be protected against dangers that may arise from contact with live paits of the installation. This protection can be achieved by one of the following methods: (i) Preventing a current from passing through the body of any person or any livestock (ii) Limiting the current which can pass through a body to an on-hazardous value. 22 131.2.2 Fault protection Persons and livestock shall be protected against dangers that may arise from contact with exposed-conductive-pmis during a fault. This protection can be achieved by one of the following methods: (i) Preventing a current resulting from a fault from passing through the body of any person or any livestock (ii) Limiting the magnitude of a current resulting from a fault, which can pass through a body, to a non-hazardous value (iii) Limiting the duration of a cmTent resulting from a fault,which can pass through a body, to a non-hazardous ti.me period. In connection with fault protection, the application of the method of protective equipotential bonding is one of the important principles for safety. 131.3 Protection against thermal effects 131.3.1 The electrical installation shall be so arranged that the risk of ignition of flammable materials due to high temperature or electric arc is minimized. In addition, dm·ing nom1al operation of the electrical equipment, there shall be minimal risk of bums to persons or livestock. 131.3.2 Persons, livestock, fixed equipment and fixed materials adjacent to electrical equipment shall be protected against harmful effects of heat or thermal radiation emitted by electrical equipment, and in particular the following: (i) Combustion, ignition, or degradation of materials (ii) Risk of burns (iii) Impairment of the safe function of installed equipment. Electrical equipment shall not present a fire hazard to adjacent materials. 131.4 Protection against overcurrent Persons and livestock shall be protected against injury, and property shall be protected against damage, due to excessive temperatures or electromechanical stresses caused by any overcurrents likely to arise in live conductors. NOTE: Protection can be achieved by limiting the overcmTent to a safe value and/or duration. 131.5 Protection against fault current Conductors other than live conductors, and any other paits intended to ca1Ty a fault current, shall be capable of carrying that cunent without attaining an excessive temperature. Electrical equipment) including conductors, shall be provided with mechanical protection against electromechanical stresses of fault currents as necessary to prevent injury or damage to persons, livestock or property. 131.6 Protection against voltage disturbances and measures against electromagnetic disturbances 131.6.1 Persons and livestock shall be protected against injury, and property shall be protected against any harmful effects, as a consequence of a fault between live parts of circuits supplied at different voltages, in accordance with Section 442. 131.6.2 Persons and livestock shall be protected against injmy, and property shall be protected against damage, as a consequence of overvoltages such as those originating from atmospheric events or from switching, in accordance with Section 443. NOTE: For protection against direct lightning strikes on the structure or nearby lightning strokes, refer to the BS EN 62305 series. 131.6.3 Persons and livestock shall be protected against injury, and property shall be protected against damage, as a consequence ofundervoltage and any subsequent voltage recovery, in accordance with Section 445. 131.6.4 The installation shall have an adequate level of immunity against electromagnetic disturbances so as to function correctly in the specified environment, in accordance with Section 444. The installation design shall take into consideration the anticipated electromagnetic emissions, generated by the installation or the iustalled equipment, which shall be suitable for the CUITent-using equipment used with, or connected to, the installation. 23  131.7 Protection against power supply interruption Where danger or damage is expected to arise due to an interruption of supply, suitable provisions shall be made in the installation or installed equipment. 132 DESIGN 132.1 General The electrical installation shall be designed by one or more skilled persons to provide for: (i) the protection of persons, livestock and property in accordance with Section 131 (ii) the proper functioning of the electrical installation for the intended use. The information required as a basis for design is stated in Regulations 132.2 to 132.5. The requirements with which the design shall comply are stated in Regulations 132.6 to 132.16. 132.2 Characteristics of available supply or supplies Information on the characteristics of the available supply or supplies shall be determined by calculation, measurement, enquiry or inspection. The following characteristics shall be included in the documentation referred to in Regulation 132.13 to show confonnity with the Regulations: (i) Nature of current: AC and/or DC (ii) Purpose and number of conductors: - forAC line conductor(s) neutral conductor protective conductor PEN conductor - forDC conductors equivalent to those listed above (outer/middle/earthed live conductors, protective conductor, PEN conductor) (iii) Values and tolerances: - nominal voltage and voltage tolerances nominal frequency and frequency tolerances maximum current allowable - prospective fault cunent exte1nal earth fault loop impedance (iv) Protective measures inherent in the supply, e.g. earthed neutral or mid-wire (v) Pa1ticular requirements of the distributor. NOTE: Jfthe distributor changes the characteristics of the power supply this may affect the safety of the installation. 132.3 Nature of demand The number and type of circuits required for lighting, heating, power, control, signalling, communication and information technology, etc. shall be determined from lrnowledge of: (i) location of points of power demand (ii) loads to be expected on the various circuits (iii) daily and yearly variation of demand (iv) any special conditions, such as harmonics (v) requirements for control, signalling, information and communications technology (vi) anticipated future demand, if specified. 24 132.4 Electrical supply systems for safety services or standby electrical supply systems Where a supply for safety services or standby electrical supply systems is specified the following shall be detennined: (i) Characteristics of the supply (ii) Circuits to be supplied by the safety source. 132.5 Environmental conditions 132.5.1 The design of the electrical installation shall take into account the environmental conditions to which it will be subjected. 132.5.2 Equipment in surroundings susceptible to risk of fire or explosion shall be so constructed or protected, and such other special precautions shall be taken, as to prevent danger. 132.6 Cross-sectional area of conductors The cross-sectional area of conductors shall be dete1mined for both normal operating conditions and, where appropriate, for fault conditions according to: (i) the admissible maximum temperature (ii) the admissible voltage drop (iii) the electromechanical stresses likely to occur due to short-circuit and earth fault currents (iv) other mechanical stresses to which the conductors are likely to be exposed (v) the maximum impedance for correct operation of short-circuit and earth fault protection (vi) the method of installation (vii) harmonics (viii) thennal insulation. 132.7 Type of wiring and method of installation The choice of the type of wiring system and the method of installation shall include consideration of the following: (i) The nature of the location (ii) The nature of the structure suppmiing the wiring (iii) Accessibility of wiring to persons and livestock (iv) Voltage (v) The electromechanical stresses likely to occur due to shmi-circuit and earth fault currents (vi) Electromagnetic interference (vii) Other external influences (e.g. mechanical, thermal and those associated with fire) to which the wiring is likely to be exposed during the erection of the electrical installation or in service. 132.8 Protective equipment The characteristics of protective equipment shall be dete1mined with respect to their function, including protection against the effects of: (i) overload (ii) fault current (iii) overvoltage (iv) undervoltage and/or loss of voltage. The protective devices shall operate at values of current, voltage and time which are suitably related to the characteristics of the circuits and to the possibilities of danger. 132.9 Emergency control An interrupting device shall be installed in such a way that it can be easily recognized and effectively and rapidly operated where, in the case of danger, there is a necessity for immediate interruption of the supply. 132.10 Disconnecting devices Disconnecting devices shall be provided so as to permit switching and/or isolation of the electrical installation, circuits or individual items of equipment as required for operation, inspection, testing, fault detection, maintenance and repair. 25  132.11 Prevention of mutual detrimental influence The electrical installation shall be arranged in such a way that no mutual detrimental influence will occur between electrical installations and non-electrical installations. Electromagnetic interference shall be taken into account. 132.12 Accessibility of electrical equipment Electrical equipment shall be arrnnged to provide: (i) sufficient space for the initial installation and later replacement of individual items of electrical equipment (ii) accessibility for operation, inspection, testing, fault detection, maintenance and repair. 132.13 Documentation for the electrical installation Every electrical installation shall be provided with appropriate documentation, including that required by Regulations 313.1, 422.1, 514.9, 536.5, Part 6 and, where applicable, Part 7 and Part 8. 132.14 Protective devices and switches 132.14.1 A single-pole fuse, switch or circuit-breaker shall be inserted in the line conductor only. 132.14.2 No switch or circuit-breaker, except where linked, or fuse, shall be inserted in an earthed neutral conductor. Any linked switch or linked circuit-breaker inse1ied in an earthed neutral conductor shall be arranged to break all the related line conductors. 132.15 Isolation and switching 132.15.201 Effective means, suitably placed for ready operation, shall be provided so that all voltage may be cut off from every installation, from evety circuit thereof and from all equipment, as may be necessary to prevent or remove danger. 132.15.202 Every fixed electric motor shall be provided with an efficient means of switching off, readily accessible, easily operated and so placed as to prevent danger. 132.16 Additions and alterations to an installation No addition or alteration, temporary or permanent, shall be made to an existing installation, unless it has been asce1tained that the rating and the condition of any existing equipment, including that of the distributor, will be adequate for the altered circumstances. Furthermore, the earthing and bonding arrangements, if necessaiy for the protective measure applied for the safety of the addition or alteration, shall be adequate. 133 SELECTION OF ELECTRICAL EQUIPMENT 133.1 General 133.1.1 Every item of equipment shall comply with the appropriate British or Harmonized Standard. In the absence of such a standard, reference shall be made to the appropriate International (IEC) standard or the appropriate standard of another country. 133.1.2 Where there ar·e no applicable standards, the item of equipment concerned shall be selected by special agreement between the person specifying the installation and the installer. 133.1.3 Where equipment to be used is not in accordance with Regulation 133.1.1 or is used outside the scope of its standard, the designer or other person responsible for specifying the installation shall confinn that the equipment provides at least the same degree of safety as that afforded by compliance with the Regulations. Such use shall be recorded on the appropriate electrical certification specified in Part 6. 133.2 Characteristics Every item of electrical equipment selected shall have suitable characteristics appropriate to the values and conditions on which the design of the electrical installation (see Section 132) is based and shall, in particular, fulfil the requirements of Regulations 133.2.1 to 4. 133.2.1 Voltage Electrical equipment shall be suitable with respect to the maximum steady-state voltage (rms value for AC) likely to be applied, as well as overvoltages likely to occur. NOTE: For certain equipment, it may also be necessary to take account of the lowest voltage likely to occur. 26 133.2.2 Current Electrical equipment shall be selected with respect to the maximum steady current (rms value for AC) which it has to cany in normal service and with respect to the current likely to be carried in abnormal conditions and the period (e.g. operating time of protective devices, if any) during which it may be expected to flow. 133.2.3 Frequency Equipment shall be suitable for the frequencies likely to occur in the circuit. 133.2.4 Power Electrical equipment which is selected on the basis of its power characteristics shall be suitable for the duty demanded of the equipment, taking into account the load factor and the normal service conditions. 133.3 Conditions of installation Electrical equipment shall be selected so as to withstand safely the stresses, the enviromnental conditions (see Regulation 132.5) and the characteristics of its location. An item of equipment which does not by design have the properties corresponding to its location may be used where adequate further protection is provided as part of the completed electrical installation. 133.4 Prevention of harmful effects All electrical equipment shall be selected so that it will not cause harmful effects on other equipment or impair the supply during normal service, including switching operations. NOTE: Examples of characteristics which are likely to have harmful effects are given in Chapter 33. 133.5 New materials and inventions Where the use of a new material or invention leads to departures from the Regulations, the resulting degree of safety of the installation shall be not less than that obtained by compliance with the Regulations. Such use shall be recorded on the appropriate electrical certification specified in Part 6. 134 ERECTION AND INITIAL VERIFICATION OF ELECTRICAL INSTALLATIONS 134.1 Erection 134.1.1 Good workmanship by one or more skilled or instmcted persons and proper materials shall be used in the erection of the electrical installation. The installation of electrical equipment shall take account of manufacturers 1 instructions. 134.1.2 The characteristics of the electrical equipment, as determined in accordance with Section 133, shall not be impaired by the process of erection. 134.1.3 Conductors shall be identified in accordance with Section 514. Where identification oftenninals is necessary, they shall be identified in accordance with Section 5 I 4. 134.1.4 Every electrical joint and connection shall be of proper construction as regards conductance, insulation, mechanical strength and protection. 134.1.5 Electrical equipment shall be installed in such a manner that the design temperatures are not exceeded. 134.1.6 Electrical equipment likely to eause high temperatures or electric arcs shall be placed or guarded so as to minimize the risk of ignition of flammable materials. Where the temperature of an exposed part of electrical equipment is likely to cause injury to persons or livestock that part shall be so located or guarded as to prevent accidental contact therewith. 134.1.7 Where necessary for safety purposes, suitable warning signs and/or notices shall be provided. 134.2 Initial verification 134.2.1 During erection and on completion of an installation or an addition or alteration to an installation, and before it is put into service, appropriate inspection and testing shall be carried out by one or more skilled persons competent to verify that the requirements of BS 7671 have been met. Appropriate certification shall be issued in accordance with Chapter 64. 27  134.2.2 The designer of the installation shall make a recommendation for the interval to the first periodic inspection and test as detailed in Chapter 64. NOTE: The requirements of Chapter 34 (Maintainability) should be taken into consideration. 135 PERIODIC INSPECTION AND TESTING 135.1 It is recommended that every electrical installation is subjected to periodic inspection and testing, in accordance with Chapter 65. 28  PART2 DEFINITIONS For the purposes of BS 7671, the following definitions shall apply. As far as practicable the definitions align with !EC 60050 - International Electrotechnical Vocabulary. NOTE: Where a section number is listed, e.g. {444}, the definition only applies within that section. 8/20 Current impulse, {534}. A cmTent impulse with a virtual front time of 8 µs and a time to half-value of 20 µs where; (i) the front time is defined as l.25(t90 - t 10 ), where t90 and t 10 are the 90 % and 10 % points on the leading edge of the waveform (ii) the time to half-value is defined as the time between the virtual origin and the 50 % point on the tail. The virtual origin is the point where a straight line drawn through the 90 % and 10 % points on the leading edge of the wavefonn intersects the I ~ 0 line. Accessory. A device, other than cuITent-using equipment, associated with such equipment or with the wiring of an installation. Agricultural and horticultural premises. Rooms, locations or areas where: livestock are kept, or feed, fertilizers, vegetable and animal products are produced, stored, prepared or processed, or plants are grown, such as greenhouses. Ambient temperature. The temperature of the