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Wiring Regulations in Brief, 2nd Edition | Ray Tricker | download
Strona główna Wiring Regulations in Brief, 2nd Edition
ISBN 10: 0750689730
ISBN 13: 978-0-7506-8973-1
Pobierz (pdf, 10.38 MB)
electrical1089
conductors935
conductor909
wiring775
circuit753
installations600
cables543
earthing521
cable461
wiring regulations402
insulation394
bonding368
installed362
circuits324
regulations in brief323
inspection316
protective conductor294
socket278
conductive273
electrical installations264
electrical installation233
electrical equipment215
rcd209
equipotential bonding207
earthed190
switching184
conductive parts182
disconnection162
exposed conductive154
neutral conductor140
socket outlets136
conduit133
enclosure132
wiring system125
overcurrent125
bonding conductors117
inspection and testing115
exceeding113
certificate112
trunking111
residual109
impedance109
external influences108
A complete guide to the requirements of the17th Edition of the
IEE Wiring Regulations, BS 7671: 2008 and Part P of the Building
Copyright © 2008, Raymond L. Tricker. Published by Elsevier Ltd,
The right of Raymond L. Tricker to be identified as the author of this work has been
No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means electronic, mechanical, photocopying, recording
or otherwise without the prior written permission of the publisher.
Department in Oxford, UK: phone (44) (0) 1865 843830; fax: (44) (0) 1865
ISBN: 978-0-7506-8973-1
Ray Tricker (MSc, IEng, FIET, FCMI, FCQI, FIRSE) is
the Principal Consultant of Herne European Consultancy –
a company specializing in Integrated Management
Systems – and an established Butterworth-Heinemann
author (39 titles). He served with the Royal Corps of
Signals (for a total of 37 years) during which time
he held various managerial posts culminating in his
being appointed as the Chief Engineer of NATO’s
Most of Ray’s work since joining Herne has centred on
the European railways. He has held a number of posts with
the Union International des Chemins de fer (UIC), for
example, Quality Manager of the European Train Control
System (ETCS), European Union (EU) T500 Review
Team Leader, European Rail Traffic Management System (ERTMS) Users’ Group
Project Co-ordinator and HEROE (Harmonization of European Rail Rules) Project
Co-ordinator, and currently (as well as writing books for Butterworth-Heinemann!) he
is busy assisting small businesses from around the world (usually on a no-cost basis)
to produce their own auditable Quality Management Systems to meet the requirements of ISO 9001:2000. He is also a Consultant to the Association of American
Railroads (AAR) advising them on ISO 9001:2000 compliance, was recently
appointed as UKAS Technical Specialist for the assessment of Notified Bodies for the
Harmonization of the trans-European high-speed rail system, and, is currently the
Quality Manager for the Trinidad Rapid Rail Project – Programme Management
Consultancy who are overseeing the Design Stage of a brand-new, multi-billion dollar
Trinidadian railway system.
1.3.1 What about the standard’s numbering
What are the objectives of the IEE Wiring
What is the legal status of the IEE Wiring
What effect does using the Regulation have
on other Statutory Instruments?
1.7.1 What is The Building Act 1984?
1.7.2 What is the Disability Discrimination Act 2005?
1.7.3 What are the Electricity at Work Regulations
1.7.4 What are the Fire Precautions (Workplace)
Regulations 1997?
1.7.5 What is the Health and Safety at Work Act 1974?
How are the IEE Wiring Regulations
What is a competent ﬁrm?
What if the work is completed by a friend, a
relative or me?
2.5.10 What if the work is completed by a contractor or
What should be included in the records of the
Requirements from the Approved Documents
Electricity distributors responsibilities
2.7.10 Electrical installation work
2.7.11 Inspection and Test
2.7.12 Additional requirements and facilities for
2.7.13 Electrical components and installations
3.5 Earth fault loop impendence
3.6 Earthing points
3.7 Main earthing terminals
3.8 Earth electrodes
3.9 Earthing conductors
3.10 Requirements from the Regulations
3.10.8 Earth faults
3.10.10 Earthing conductors
3.10.11 Earthing systems
3.10.12 Electrical separation
3.10.13 Electrical services
3.10.14 Emergency switching
3.10.15 Earthing terminals or bars
3.10.16 Fault protection
3.10.17 High leakage current
3.10.18 Isolation
3.10.19 Protective and neutral (PEN) conductors
3.10.20 Protective bonding conductors (PME)
3.10.21 Protective conductors
3.10.22 Protective devices
3.10.23 Protective devices and switches
3.10.24 Protective earthing
3.10.25 Protective measures
3.10.26 RCDs
3.10.27 Requirements for SELV and PELV circuits
3.10.28 Sources
3.10.29 Warning notices: earthing and bonding connections 91
3.10.30 Warning notices: periodic inspection and testing
3.10.31 Testing
3.10.32 Special locations an installations
3.10.33 TN System
3.10.34 TN-C system
3.10.35 TN-S system
Design, installation, inspection and testing of
Protection by obstacles and placing out
Protection by RCDs
Requirements from the Regulations – basic
Protection by earthed equipotential bonding and
automatic disconnection of supplies (EEBADS)
Protection by obstacles and placing out of reach
Requirements from the Regulations – fault protection
Requirements from the regulations
Locations with risks of ﬁre due to the nature of
processed or stored materials
5.3.2 Protection against fault current only
5.5.1 Protection against fault current only
5.5.2 Devices for protection against overcurrent
Functional switching devices
5.6 Heaters
Heaters for liquids or other substances having
Water heaters having immersed and uninsulated
5.6.4 Electric surface heating systems
5.6.5 Electric ﬂoor heating systems
5.7 Isolators
5.8 Lampholders
5.9 Luminaires
General requirements for installations
5.9.4 Protection against ﬁre
Independent lamp controlgear, e.g. ballasts
Requirements for outdoor lighting installations,
5.9.10 Underwater luminaires for swimming pools
5.9.11 Luminaires in fountains
5.9.12 Luminaires and lighting installations in agricultural
and horticultural premises
5.9.13 Luminaires and lighting installations in exhibitions
shows and stands
5.9.14 Electric discharge lamp installations
5.9.15 Luminaires in caravans and motor
5.9.16 Luminaires in temporary installations
5.10 Mobile equipment
5.11 Plug and socket outlets
5.12 Protection by RCDs
5.12.9 Devices for protection against the risk of ﬁre
5.12.10 Electrode water heaters and boilers
5.12.11 Outdoor lighting installation
5.13 Residual current monitor (RCM)
5.14 Rotating machines and motors
5.15 Supplies
5.16 Switches
Single-pole switching devices
5.16.7 Main switches
Main linked switches
5.16.10 Functional switching devices
5.16.11 Fireﬁghter’s switches
5.16.12 Switchboards
5.16.13 Mechanical maintenance
5.16.14 Lighting installations
5.16.15 Special installations and locations
5.17 Rectiﬁers
5.18 Transformers
ELV transformers and electronic converters
Electric ﬂoor heating systems
Armoured single-core cables
Cable conduit, ducting, trunking, tray and ladder
Cables in thermal insulation
Connection of multiwire, ﬁne wire and very ﬁne
Cross-sectional areas of conductors of cables
Current-carrying capacities of cables
Electrical connections to bare connectors and/or
Electromechanical stresses
Groups containing more than one circuit
Heating conductors and cables
Identiﬁcation of conductors
Lifts and/or the proximity to non-electrical services
Omission of identiﬁcation by colour or marking
Precautions within a ﬁre-segregated compartment
Reduced low-voltage system
Requirements for SELV and PELV circuits
6.1.37 Temperature
6.1.38 Types of wiring system
6.1.39 Underground cables
6.1.40 Vibration
6.1.41 Wiring systems
6.1.42 Special installations and locations
Types of protective conductor
Automatic disconnection in case of a fault
Non-earthed equipotential bonding conductor
6.2.9 Building design
6.2.10 Cable couplers
6.2.11 Cross-sectional area of conductors
6.2.12 Conductors in parallel
6.2.13 Current-carrying capacities of conductors
6.2.14 Earthing conductors
6.2.15 Earthing requirements
6.2.16 Main earthing terminals or bars
6.2.17 Electric ﬂoor heating systems
6.2.18 Electrical connections
6.2.19 Electrical installations
6.2.20 Electrode water heaters and boilers
6.2.21 Electromechanical stresses
6.2.22 Emergency switching
6.2.23 Enclosures
6.2.24 Fault protection
6.2.25 Fault protection
6.2.26 Ferromagnetic enclosures: electromagnetic effects
6.2.27 Final circuits
6.2.28 Fire risk
6.2.29 Fuses
6.2.30 Functional switching
6.2.31 Harmonic currents
6.2.32 Identiﬁcation of conductors
6.2.33 Identiﬁcation of conductors by letters and/or
6.2.34 Notices
6.2.35 Installation
6.2.36 Inspection
6.2.37 Isolation
6.2.38 Line conductors
Multiwire, ﬁne wire and very ﬁne wire
6.2.44 Neutral conductor
6.2.45 Non-conducting location
6.2.46 Multicore cables, conduits, ducting systems,
franking systems or tray or ladder systems
6.2.47 Multiphase circuits
6.2.48 Operational conditions
6.2.49 Overhead conductors
6.2.50 Parallel conductors
6.2.51 Plug and socket outlets
6.2.52 Protective conductors
6.2.53 PEN conductors
6.2.54 Protection against fault current
6.2.55 Protection against ﬁre
6.2.56 Protection against overcurrent
6.2.57 Protection against overload current
6.2.58 Protection by earth-free local equipotential
6.2.59 Protective conductors
6.2.60 Protective devices and switches
6.2.61 Protective earthing
6.2.62 Protective equipotential bonding
6.2.63 Protective multiple earthing
6.2.64 RCDs
6.2.65 SELV and PELV circuits
6.2.66 Supply source
6.2.67 Transformers
6.2.68 Testing
6.2.69 Wiring systems
Hot water and/or steam appliances
7.1.9 Overhead wiring systems
7.1.10 Type of demand
7.1.11 Water heaters and boilers
7.2.1 Agricultural and horticultural premises
7.2.2 Conducting locations with restricted movement
7.2.3 Construction and demolition sites
7.2.4 Electrical installations in caravan/camping parks
Electrical installations in caravans and motor
7.2.10 Mobile and transportable units
7.2.11 Rooms and cabins containing saunas
7.2.12 Solar, photovoltaic (PV) power supply systems
7.2.13 Swimming pools and other basins
7.2.14 Temporary electrical installations for structures,
amusement devices and booths at fairgrounds,
7.3.10 Mobile and transportable units
7.3.11 Rooms and cabins containing saunas
7.3.12 Solar, pholtovoltaic (PV) power supply
7.3.13 Swimming pools and other basins
7.3.14 Temporary electrical installations for structures,
Environmental factors and inﬂuences
8.1.1 Combined environmental factors
8.1.2 Sequences of environmental factors
8.1.3 Environmental application
8.1.4 Environmental conditions
8.1.5 Equipment situations
8.1.6 Requirements from the Regulations – General
8.1.7 Requirements from the Regulations – General
8.2.1 Electrical installations
8.2.2 Typical requirements – ambient temperature
8.2.3 Requirements from the Regulations – ambient
8.3.1 What are the effects of solar radiation?
8.3.2 Photochemical degradation of material
8.3.3 Effects of irradiance
8.3.4 Heating effects
8.3.5 Typical requirements – solar radiation
8.3.6 Requirements from the Regulations – solar radiation
8.4.1 What is humidity?
8.4.2 Relative and absolute humidity and their effect on
8.4.3 Condensation
8.4.4 Adsorption
8.4.5 Absorption
8.4.6 Diffusion
8.4.7 Protection
8.4.8 Typical requirements – humidity
8.4.9 Requirements from the Regulations – humidity
8.5.1 Low air pressure
8.5.2 Typical requirements – air pressure and altitude
8.6.1 Water
8.6.2 Salt water
8.6.3 Ice and snow
8.6.4 Weathering
8.6.5 Typical requirements – weather and precipitation
8.6.6 Requirements from the Regulations – weather and
Typical requirements – pollutants and contaminants 453
8.8 Mechanical
8.8.1 Shock
8.8.2 Vibration
8.8.3 Acceleration
8.8.4 Protection
8.8.5 Typical requirements – mechanical
8.8.6 Requirements from the Regulations – mechanical
8.9 Electromagnetic compatibility
8.9.1 Typical requirements
8.9.2 Requirements from the Regulations – electromagnetic
8.10 Fire
8.10.1 Fire growth
8.10.2 Flashover
8.10.3 Characteristics of smoke and gases as a ﬁre
8.10.4 Building designs
8.10.5 Test Standards
8.10.6 Other related standards and speciﬁcations
8.10.7 Typical contract requirements – ﬁre
8.10.8 Requirements from the Regulations – ﬁre
9.2.2. Inspection check list
Requirements from the Regulations – inspection
9.3.7 Protection against direct and indirect contact
9.3.8 Protection against direct contact
9.3.9 Protection against indirect contact
9.3.10 Additional tests with the supply connected
9.3.11 Insulation tests
9.3.12 Veriﬁcation tests
9.3.13 Electrical connections
9.3.14 Tests for compliance with the Building
9.3.15 Additional tests required for special installations
Identiﬁcation and notices
9.4.2 Conductors
9.4.3 Identiﬁcation of conductors by letters and/or
9.4.4 Omission of identiﬁcation by colour or marking
9.4.5 Diagrams
9.4.6 Warning notices
What type of certiﬁcates and reports are there?
9.5.1 Electrical Installation Certiﬁcate
9.5.2 Minor Electrical Installation Works Certiﬁcate
9.5.3 Periodic inspection
Test requirements speciﬁc for compliance with the
9.6.10 Socket outlets
9.6.11 Switches
9.6.12 Telephone points and TV sockets
9.6.13 Equipment and components
9.6.14 Thermostats
9.6.15 Lighting
9.6.16 Lecture/conference facilities
9.6.17 Cellars or basements
Control of inspection, measuring and test
9.7.2 Computers
9.8 Requirements from the Regulations – testing
Certiﬁcation and reporting
10.2.2 Installation of equipment
10.2.3 Power supplies
10.2.4 Earthing
10.2.5 Cables
10.2.6 Conductors
10.2.7 Wiring systems
10.2.8 Protective devices
10.2.9 Electromechanical stresses
10.2.10 Electromagnetic comparability
10.2.11 Thermal effects
10.2.12 Initial veriﬁcation
10.3 Maintenance and repair
10.3.1 Frequency of inspection and testing
10.3.2 Accessibility of electrical equipment
10.3.3 Safety protection
10.3.4 Switching off for mechanical maintenance
10.3.5 Devices for switching off for mechanical
10.3.6 Connections
10.3.7 Insulating enclosure
10.3.8 Low power supply sources
10.3.9 Multiphase sequence
10.3.10 Environmental aspects
10.4 Repair
10.4.1 Disconnecting devices
10.4.2 Accessibility of electrical equipment
10.4.3 Certiﬁcation and reporting
10.5 Additions and alterations to an installation
10.5.1 Additions and alterations to an installation
10.6 Material changes of use
List of electrical and electromechanical symbols
British Standards currently used with the
too much of a surprise to learn that the committee responsible for writing
the Public Health Act of 1875 had overlooked the increased use of electric
power for street lighting and/or domestic purposes. Electricity was beginning
to become increasingly popular but, as there were no rules and regulations
governing their installation at that time, the companies or person responsible
simply dug up the roads and laid the cables as and where they felt like it!
From a Health and Safety point of view the Government of the day
expressed extreme concern at this exceedingly dangerous situation and so
in 1882 The Electric Lighting Clauses Act (modelled on the previous 1847
Gas Act) was passed by Parliament. This legislation was implemented by
Rules and Regulations for the prevention of Fire Risks Arising from Electric
Lighting and it is this document that is the forerunner of today’s IEE Wiring
Regulations. Since then, this document has seen a succession of amendments, new editions and new titles and has now become the 17th edition of
the IEE Wiring Regulations (i.e. BS 7671:2008 ‘Requirements for Electrical
Installations’).
The current legislation for all Building Control is the Building Act 1984,
which is implemented by the Building Regulations 2000 and these Building
Regulations are a set of minimum requirements designed to secure the health,
safety and welfare of people in and around buildings and to conserve fuel and
energy in England and Wales. They are basic performance standards which
are supported by a series of documents that correspond to the different areas
covered by the regulations. These are called ‘Approved Documents’ and they
contain practical and technical guidance on ways in which the requirements
of the Building Act 1984 can be met.
therefore, been a direct link between Electrical Installations and Building
Control and parts of all of the Approved Documents have an affect on
these sorts of installation. With the publication of Approved Document P
for ‘Electrical Safety’ in 2005, however, the design, installation, inspection
and testing of electrical installations has now become inextricably linked to
Building Control and the purpose of this book is attempt to draw all of the
various requirements together.
on the subject of electrical installations, but the aim of Wiring Regulations
in Brief is not just to become another book on the library shelf to be occasionally looked at. The intention is that it will provide professional engineers,
students and (i.e. to a lesser degree) the unqualified DIY fraternity with an
easy-to-read reference source to the official requirements of BS 7671:2008
for electrical safety and electrical installations.
Although BS7671:2008 is well structured and has separate sections for all
the main topics (e.g. safety protection, selection and erection of equipment
and so on) it is not the easiest of standards to get to grips with for a particular
situation. Occasionally it can be very confusing and requires the reader to
constantly flick backwards and forwards through the book to find what it is
For example, Regulation 411.4.7 states that: ‘Where a circuit-breaker
is used to satisfy the requirements of Regulation 411.3.2.2 or Regulation
411.3.2.3, the maximum value of earth fault loop impedance (Zs) shall be
determined by the formula in Regulation 411.4.5. Alternatively, for a nominal
voltage (Uo) of 230 V and a disconnection time of 0.4 s in accordance with
Regulation 411.3.2.2 or 5 s in accordance with Regulation 411.3.2.3, the values
specified in Table 41.3 for the types and ratings of overcurrent devices listed
may be used instead of calculation.’
some of this confusion and ‘officialise’ and provide the reader with an
on-the-job reference source that can be quickly used without having to delve
backwards and forwards though the standard.
important aspects of the Wiring Regulations and their association with the
Building Regulations. It should, therefore, only be treated as an aide mémoire
to the Regulations and electricians should always consult BS 7671 to satisfy
Main changes in the 2008 edition of BS 7671
Following a full review, the 17th edition of the IEE Wiring Regulations BS
7671:2008 replaces the previous 2001 16th edition.
Technical authority for this Standard is vested in the Joint IET/BSI
Technical Committee JPEL/64. This Joint Technical Committee is responsible
for the work previously undertaken by the IEE Wiring Regulations Technical
Committee and the BSI Technical Committee PEL/64. Copyright is held
jointly by the IET and BSI.
The latest edition of the Wiring Regulations (i.e. BS 7671:2008 Requirements
for Electrical Installations) was issued on 1 January 2008 and came into effect
on 1 July 2008. Installations designed after 30 June 2008 are to comply with
BS 7671:2008.
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 new edition in every respect, but this
does not necessarily mean that they are unsafe for continued use or require
BS 7671:2008 includes changes necessary to maintain technical alignment
with CENELEC harmonisation documents and a summary of the main changes
Continuity of service now requires that an assessment be made for each
Documentation for all electrical installations must now be provided.
FELV is recognised as a protective measure and new requirements are
New additional requirements to ensure the safe connection of low voltage
generating sets including small-scale embedded generators (SSEGs) have
now been included.
Protection against electric shock now refers to protection under normal
conditions (previously referred to as protection against direct contact)
and fault protection (previously referred to as protection against indirect
Protection against overvoltages of atmospheric origin or due to switching has additional regulations enabling designers to use a risk assessment
approach when designing installations which may be susceptible to overvoltages of atmospheric origin.
Protection of low-voltage installations against temporary overvoltages due
to earth faults in the high-voltage system and due to faults in the low-voltage
system have now been included.
Requirements concerning the UK reduced low-voltage system are now
Requirements to protect against voltage disturbances and implement
measures against electromagnetic influences have now been included.
Requirements for safety services (e.g. emergency escape lighting, fire alarm
systems, installations for fire pumps, fire rescue service lifts, smoke and
heat extraction equipment) now need to be observed.
Safety services have been expanded in line with IEC standardization.
Selection and erection of wiring systems now includes busbar trunking
systems and powertrack systems.
The requirement that a metallic pipe of a water utility supply shall not
be used as an earth electrode is retained and other metallic water supply
pipework (such as a privately owned water supply network) shall now
not be used as an earth electrode unless precautions are taken against its
removal and it has been considered for such a use.
There is a new series of regulations for luminaries and lighting
Inspection and testing (which was Part 7 of BS 7671:2001) has been
restructured as a new Part 6 and now includes changes to the requirements
for insulation resistance, when testing SELV and PELV circuits at 250 V
and for systems up to and including 500 V (including FELV).
Special installations or locations (which was previously Part 6 of
BS 7671:2001) has now been restructured and expanded as a new Part 7
with the following major amendments:
 Agricultural and horticultural premises:
 additional requirements applicable to life support systems have now
 the reduced disconnection times (0.2 s) and the 25 V equation no longer
 Construction and demolition site installations:
 Electrical installations in caravan/camping parks and similar locations:
 now includes the requirement that each socket-outlet must be provided,
individually, with overcurrent and RCD protection.
 Locations containing a bath tub or shower basin:
 each circuit in the special location must have 30 mA RCD protection
 Supplementary bonding is no longer required providing the installation
has main bonding in accordance with Chapter 41
 socket-outlets (other than SELV and shaver supply units to BS EN
61558-2-5) may be installed in locations containing a bath or shower
3 m horizontally beyond the boundary of zone 1
 zone 3 is no longer defined.
 Rooms and cabins containing sauna heaters:
 zones A, B, C and D in BS 7671:2001 are replaced by zones 1, 2 and 3
(with changed dimensions).
 Swimming pools and other basins:
 this special location now includes basins of fountains
 zones A, B and C in BS 7671:2001 are replaced by zones 0, 1 and 2.
The following new sections have also been included in Part 7:
temporary electrical installations for structures, amusement devices and
booths at fairgrounds, amusement parks and circuses.
Note: For some reason the numbering system of section 7 of BS 7671:2008 is
not sequential, so you will need to be careful.
The following new appendices have also been included:
definitions concerning multiple source, d.c. and other systems
effect of harmonic currents on balanced three-phase systems
measurement of earth fault loop impedance (consideration of the increase
of the resistance of conductors with increase of temperature)
methods for measuring the insulation resistance/impedance of floors and
walls to earth or to the protective conductor system
voltage drop in consumers’ installations.
To reflect these changes, this second edition of Wiring Regulations in Brief is
description of its unique numbering system, objectives and
legal status. The effect that the Wiring Regulations have
on other Regulations and how this British Standard can be
The requirements of the Building Act 1984 together with the
Building Regulations:2000 and their Approved Documents
(which provide guidance for conformance) and how these
Building Control Regulations inter-relate with the Wiring
Regulations. A resumé of the responsibilities for electrical
installations. The types of inspections and tests that have to
be completed and the requirements for records. The contents
of Approved Document P for electrical safety and other
relevant Approved Documents (such as those for Fire Safety,
Access and Facilities for Disabled People, Conservation of
Fuel and Power, Resistance to the Passage of Sound etc.)
together with a listing of all the most important requirements
that directly concern electrical installations.
Note: Whilst the requirements from the Wiring Regulations are normally prefaced by the word ‘shall’ (meaning that this section is a mandatory requirement), you will notice that the Building Regulations use the words ‘should’
(i.e. recommended), ‘may’ (i.e. permitted) or ‘can’ (i.e. possible).
The reason for this is that Approved Documents reproduce the actual
requirements contained in the Building Regulations relevant to a particular
subject area. This is then followed by practical and technical guidance
(together with examples) showing how the requirements can be met in some
of the more common building situations. There may, however, be alternative
ways of complying with the Building Regulations 2000’s requirements to
those shown in the Approved Documents and you are, therefore, under no
obligation to adopt any particular solution in an Approved Document – if you
prefer to meet the requirement(s) in some other way – but you must meet the
types of earthing systems and earthing arrangements. It
then lists all the main requirements for earthing before
briefly touching on the test requirements for earthing.
Chapter 4 lists the main requirements for safety
protection. Basic protection against electric shock,
fault protection, protection against both direct and
indirect contact, protective conductors and protective
equipment and then lists the test requirements for
The intention of this chapter, therefore, is to provide
a catalogue of all the different types identified and
referred to in the Wiring Regulations (e.g. luminaires,
RCDs, plugs and sockets etc.) and then make a list of
the specific requirements that are sprinkled throughout
the Regulations. For your convenience this catalogue
has been compiled in alphabetical order.
ducting, cable trunking and so on. Unfortunately,
as is the case for equipment and components, the
requirements for these items is liberally sprinkled
The aim of Chapter 6, therefore, is to provide a
referred to in the Wiring Regulations in three main
headings (namely cables, conductors and conduits/etc)
and then make a list of their essential requirements.
installations in buildings, there are also some indoor
and out-of-doors special installations (such as floor
and central heating systems) and locations (such
as swimming pools) that are subject to special
requirements owing to the extra dangers they pose.
Chapter 7 considers the requirements for these special
locations and installations.
The new edition of BS 7671 now includes far
more details of the regulations concerning external
influences and (i.e. in Appendix 5 to BS 7671:2008)
provides a concise list of environmental influences.
Chapter 8 of this editon of the book provides guidance
on all forms of external influence. Also included in
this chapter are extracts from the current Regulations
that have an impact on the environment.
testing. Without this prerequisite, it could be quite
Chapter 9 provides a consolidated list of how electrical
installations shall be inspected and tested as well as a
brief insight into some of the test equipment that may
Appendix A: Symbols used in electrical installations
Appendix B: List of electrical and electromechanical symbols
Appendix C: SI units for existing technology
Appendix E: British Standards currently used with the Wiring Regulations
(by standard and by title)
Appendix F: List of useful contacts and further information
It is hoped that the following symbols will help you get the most out of
legal/statutory requirement).
A good idea or a useful reminder.
For your assistance, I have also highlighted all the really essential and/or
An RCD shall not be used in a TN-C system.
WR-411.4.4
For your convenience (and to save you having to look backwards and forwards through the book for the correct Requirement) quite of a lot of these
Requirements have been shown more than once (i.e. in different chapters and/
or sections of the book – as have a few of the figures and tables.
areas where perhaps they feel I have not given sufficiently coverage, omissions
and/or mistakes etc.) then please let know by emailing me at ray@herne.org.uk
and I will make suitable amendments in the next edition of this book.
I would like to thank the Institution of Engineering and Technology (IET) for
giving me permission to reproduce the following Tables and Figures:
Tables 3.1, 3.2, 3.3, 3.4, 4.1, 6.2, 6.6, 6.7, 6.11, 8.4, 8.5, 8.18, and 9.13,
and Figures 5.2, 5.3, 6.6, 6.7 and 10.2 which are taken from The IEE Wiring
Regulations: BS7671: 2001 incorporating Amendments 1 & 2: 2004 (The
IEE, London, UK in agreement with BSI, 2004) ISBN 0863413730.
Figures 9.2, 9.3, 9.4 and 9.6 which are taken from The IEE On-Site Guide
(BS 7671: 2001 16th edition Wiring Regulations including Amendments 1 &
2: 2004) (IEE Publications, 2004) ISBN 0863413749.
I would also like to thank the following organizations for providing me
with assistance in the preparation of this book and for giving me permission
to use copy-righted materials for illustration purposes in the following tables
BRE Certification Ltd for use of their logo in Figure 2.3
Figure 5.5 and Tables 5.3, 5.4, 5.5, 6.12, 8.7 and 9.6
CORGI Competent Persons Scheme for use of their logo in Figure 2.3
ELECSA Ltd for use of their logo in Figure 2.3
NAPIT Certification Ltd for use of their logo in Figure 2.3
NICEIC for use of their logo in Figure 2.3
OFTEC for use of their logo in Figure 2.3
TrustMark for use of their logo in Figure 2.4
Note: Please see Appendix F for full contact details for these organizations.
In addition I would like to give due recognition to the following tables and
figures which are reprinted by kind permission from Elsevier.
Edition, Hughes and Ferrett, 2005, ISBN 0750666234.
Tables 4.2 and 6.4, and Figures 3.13, 3.14, 3.15, 3.17, 4.1, 4.3, 4.8,
4.10 and the inside cover diagrams are taken from 17th edition IEE Wiring
Regulations: explained and Illustrated, eighth edition, Scaddan, 2008, ISBN
9780750687201.
Figures 2.3, 2.5, 2.6, 2.8, 2.9, 2.10, 2.11, 9.16, 9.17, 9.19 and 9.21
from Building Regulations in Brief, fourth edition, Tricker, 2006, ISBN
075068058X.
Note: The BSI logo, Kitemark and the Kitemark symbol are produced with
permission of the British Standards Institute and are the Registered Trademarks
of such in the United Kingdom, and others apply in other countries around the
The IEE Wiring Regulations is a 389-page document that defines the way in
The current edition of the Regulations is BS 7671:2008: Requirements for
Electrical Installations, IEE Wiring Regulations (Seventeenth Edition), more
commonly referred to as ‘The Red Book’ or ‘the 17th edition’.
Figure 1.1 Front cover of BS 7671:2008
British Electrotechnical Committee – who are the UK national body responsible for formal standardisation within the electrotechnical sector) in partnership with the BSI (i.e. the British Standards Institution – who have ultimate
responsibility for all British Standards produced within this sector) and The
Institution of Engineering and Technology (IET) – who, with more than
135,000 members, are Europe’s largest grouping of professional engineers
involved in power engineering, communications, electronics, computing, software, control, informatics and manufacturing.
The technical authority for this standard is The National Committee
for Electrical Installations (JPEL/64), which is a Joint IET/BSI Technical
Committee responsible for all the work previously undertaken by the IEE
Wiring Regulations Committee and BSI Technical Committee PEU64.
Copyright is jointly held by BSI and the IET.
7671:2008, Requirements for Electrical Installations.
BS 7671:2008 was issued on 1 January 2008 and came into effect on 1 June
All installations that were (or are) designed after 1 June 2008 must comply
no existing rules and regulations available to control electrical installations
and so the electricity company just dug up the roads and laid the cables in the
gutters. This particular electricity supply was discontinued in 1884.
street lighting. Once more, there was no one in authority to tell the electricity
supplier how to lay the cables and their positioning was, therefore, dependent
on the electrician responsible for that particular section of the work.
Later on in 1882, The Electric Lighting Clauses Act (modelled on the previous 1847 Gas Act) was passed by Parliament and this enabled the Board
of Trade to authorise the supply of electricity in any area by a local authority, company or person and to grant powers to install this electrical supply
(including breaking up the streets) through the use of the 1882 Rules and
Regulations for the prevention of Fire Risks Arising from Electric Lighting.
This document was the forerunner of today’s IEE Wiring Regulations.
Historically, since 1882, there has been a succession of amendments and
new editions of the Regulations as shown in Table 1.1.
By now this continual updating was seen as a bit of a problem, particularly
to designers and installers who had to ensure that they were always working
Reprinted 1958, 1961, 1962 and 1964
Reprinted 1968, 1969, 1970 (in metric units), 1972,
in compliance to the latest Regulations. With the publication of the fifteenth
edition, therefore, it was decided that in future, reprints of the same edition
would be contained in one of five different-coloured covers (i.e. red, green,
yellow, blue and brown) and a new edition would be published when the
brown-covered reprint required updating.
Table 1.2 BS 7671:2001 – Publication details
BS 7671:2001 issued Jun 2001 (see Note
Reprinted incorporating Amendments No
1 and No 2
New edition aligned with existing and
new CENELEC, IEC and EN Harmonised
Note: BS 7671:2008 includes some important changes that were required
The structure of BS 7671:2008 is given in Table 1.3.
Table 1.3 BS 7671:2008 – Structure
into account in choosing and applying the requirements of the subsequent
Parts of the Regulations.
Any intended departure from the requirements of Parts 1 to 6 requires special consideration by the installation designer and must be documented in the
Electrical Installation Certificate specified in Part 6.
Appendices (Table 1.4).
Table 1.4 BS 7671:2008 – Appendices
British and other
reference is made in
Reproduced in the Reference section of this
legislation and EU Harmonised Directives
that electrical installations are required to
devices and RCDs
Details of time/current characteristics for:
● RCDs.
drop for cables and
● installation methods for conductors and
cables (e.g. cleated, in conduits, on trays,
in trenches)
● cable specifications and current rating
tables (e.g. armoured cables, mineral
insulated cables, fire-resistant cables,
● correction factors (for groups of cables,
mineral insulated cables, cables installed
in trenches, ambient temperature where
protection is against short circuits and
● copper conductors
● aluminium conductors.
Lists and schedules of external influences
having an influence on electrical installations
Model forms for
Reproduced in Part 6 of this book.
Current details of cable core marking and
colours that are to be used in all installations
(for details see inside front and back cover of
drop for busbar trunking
and powertrack systems
● the basis of current-carrying capacity
● rating factors for current-carrying capacity
of busbar trunking systems
● effective current-carrying capacity
● protection against overload current
● voltage drop.
Definitions – multiple
sources, d.c. and other
Examples of TN-C, TN-S, TN-C-S, TT and
in parallel against
● overload protection of conductors in
● short circuit protection of conductors in
Effect of harmonic
currents on balanced
three-line systems
Information about rating factors for triple
harmonics (examples and details of
harmonic currents in line conductors)
Information concerning the maximum
allowable value of voltage drop.
the insulation resistance/
impedance of floors and
walls to earth or to the
Test electrodes.
fault loop impedance:
of conductors with increase
Ring and radial final circuit
Information concerning Section 433.1.5.
The numbering system used to identify specific requirements in BS
7671:2006 is as follows:
The first digit signifies a Part.
The second digit signifies a Chapter.
The third digit signifies a Section.
Subsequent digits signify the Regulation number.
Section number 413 is made up as follows:
Chapter 41 (first chapter of Part 4) – Protection against electric shock.
Section 413 (third section of Chapter 41) – Protective measure:
1.4 What are the objectives of the
IEE Wiring Regulations?
Current legal requirements for employee competence in electrical work now
call for everyone involved in certain electrical activities – for example, simply
choosing the size of cable or fuse – to be aware of the regulative requirements
associated with such work. BS 7671:2008 (i.e. The IEE Wiring Regulations)
is the traditionally approved Code of Practice for those who are involved in
(or supervise) electrical work such as electrical maintenance, control and/or
The stated intention of wiring safety codes is to ‘provide technical, performance and material standards that will allow sufficient distribution of electrical energy and communication signals, at the same time protecting persons
in the building from electric shock and preventing fire and explosion’ (IET).
To ensure the protection of people and livestock from fire, shock or
burns from any installation that complies with their requirements.
1.5 What is the legal status of the
throughout Europe, they had no legal status and did not require Continentals
who were carrying out installation work in the UK to abide by them. This
problem was overcome in October 1992 when the lEE Wiring Regulations
became a British Standard, BS 7671 – thus providing them with national/
Note: Although the Regulations are non-statutory regulations they may,
however, be used as evidence in a court of law to claim compliance with a
1.6 What do they cover?
As shown below, the IEE Wiring Regulations cover both electrical installations and electrical equipment.
Electrical installations (or installation) means any assembly of associated electrical equipment supplied from a common origin to fulfil a specific purpose and having certain co-ordinated characteristics.
installations such as those of:
agricultural and horticultural premises;
caravans, caravan parks and similar sites;
construction sites, exhibitions, shows, fairgrounds and other installations for
temporary purposes including professional stage and broadcast applications;
external lighting and similar installations;
mobile or transportable units;
public premises;
low-voltage generating sets;
highway equipment and street furniture;
Note: ‘Premises’ covers the land and all facilities including buildings belonging to it.
the addition to (or alteration of) installations and parts of existing installations affected by an addition or alteration;
circuits (but not apparatus and/or equipment internal wiring) operating
at voltages greater than 1000 V and derived from an installation having
precipitators);
circuits supplied at nominal voltages up to and including 1000 V a.c. or
1500 V d.c.;
Note: although the preferred frequencies are 50 Hz, 60 Hz and 400 Hz, the
use of other frequencies for special purposes is not excluded
consumer installations external to buildings;
fixed wiring for communication and information technology, signalling,
wiring systems and cables not specifically covered by the Standards for
in certain cases, they may need to be supplemented by the requirements and/or
recommendations of other British Standards or by the requirements of the person ordering the work. Such cases could include (among others) the following:
design and installation of temporary distribution systems delivering a.c.
electrical supplies for lighting, technical services and other entertainment
related purposes – BS 7909;
electrical equipment for explosive gas atmospheres – BS EN 60079;
electrical equipment for use in the presence of combustible dust – BS EN
50281 and BS EN 61241;
BS 559 and BS EN 50107;
electric surface heating systems – BS 6351;
electrical installations for open-cast mines and quarries – BS 6907;
emergency lighting – BS 5266;
fire detection and alarm systems in buildings – BS 5839;
telecommunications systems – BS 6701.
Continuity Regulations 2002;
electrical equipment of machines covered by BS EN 60204;
equipment of mobile and fixed offshore installations;
equipment on board ships;
lightning protection systems for buildings and structures covered by
BS EN 62305;
Regulations concerning caravans are applicable);
of the electrical installation);
railway traction equipment, rolling stock and signalling equipment;
those aspects of lift installations covered by relevant parts of BS 5655 and
BS EN 81-1;
Note: For installations in premises, which are subject to statutory control
(e.g. via a licensing or other authority), the requirements of that authority will
need to be confirmed and these requirements then complied with in the design
and implementation of those installations.
generation, conversion, transmission, distribution or utilisation
of electrical energy, such as machines, transformers, apparatus,
measuring instruments, protective devices, wiring systems, accessories, appliances and luminaires.
1.7 What effect does using the Regulation
have on other Statutory Instruments?
The requirements of the IEE Wiring Regulations also have an effect on the
the Building Act 1984;
the Fire Precautions Act 1971;
The Building Act 1984 (as implemented by the Building Regulations 2000)
is the enabling Act under which all Building Regulations have been made.
The Secretary of State (under the power given in the Building Act 1984) is
buildings and of others who may be affected by buildings or matters connected with buildings;
further the conservation of fuel and power;
and may make regulations with respect to the design and construction of
buildings and the provision of services, fittings and equipment in (or in) connection with) buildings.
Note: The current regulations governing the Building Regulations 2000
are SI 2000/2531 (as amended) – a copy of which can be downloaded from:
www.opsi.gov.uk/si/si2000/20002531.
Figure 1.2 The Building Act 1984
of electrical safety within buildings (domestic and non-domestic) based on voluntary controls centred around BS 7671. With the growing number of electrical
accidents occurring in the ‘home’, the government has now been forced to implement a legal requirement for safety in all electrical installation work in dwellings.
As from 1 January 2005, therefore, all new electrical wiring or electrical
components for domestic premises (or small commercial premises linked to
domestic accommodation) must be designed and installed in accordance with
the Building Regulations, Part P (which is based on the fundamental principles
set out in Chapter 13 of BS 7671:2008).
In addition, all fixed electrical installations (i.e. wiring and appliance fixed to
the building fabric such as socket-outlets, switches, consumer units and ceiling fittings) must now be designed, installed, inspected, tested and certified
to BS 7671.
Note: Part P only applies to fixed electrical installations that are intended to
operate at low-voltage or extra-low-voltage which are not controlled by the
Electricity Supply Regulations 1988 as amended, or the Electricity at Work
Regulations 1989 as amended.
has been completed by a ‘Competent Person’ who is able to self-certify the
For more details about the Building Regulations, visit: http://www.communities.
gov.uk/index.asp?id  1130474 or see Building Regulations in Brief, 5th edition (ISBN 978-0-7506-8444-6).
Figure 1.3 The Disability Discrimination Act 2005
The Disability Discrimination Act 1995 (DDA) is: an Act to make it unlawful
to discriminate against disabled persons in connection with employment, the
provision of goods, facilities and services or the disposal or management of
premises; to make provision about the employment of disabled persons; and
to establish a National Disability Council.
From the point of view of BS 7671:2001, the Disability Act 1995 as
for a trade organisation to discriminate against a disabled person;
for a qualifications body to discriminate against a disabled person;
For more details about the DDA see: http://www.direct.gov.uk/en/Disabled
1.7.3 What are the Electricity at Work Regulations 1989?
Figure 1.4 The Electricity at Work Regulations 1989
The Electricity at Work Regulations 1989 impose health and safety requirements with respect to electricity used at work. General duties are imposed to
all electrical systems have been properly constructed and maintained, and
are used in such a way so as not to give rise to danger;
responsibilities for safety fall with the Employer or Self-Employed Person
who employs one or more individuals under a Contract of Employment;
maintenance of fixed electrical installations and portable appliances is carried out and regular inspections are made to ensure their safety;
persons responsible for buildings or electrical installations and appliances
ensure that electrical test certificates confirming the installations and
appliances have been tested are in place.
Note: The Electricity at Work Regulations 1989 also state that where an
accident occurs and it is found that the systems are not covered by a valid test
certificate, the Health & Safety Executive (HSE) takes a keen interest in prosecutions resulting from electrocution or death within the workplace. Reducing
the risk of such an accident is a legal requirement.
all electrical systems shall be constructed and maintained to prevent
all electrical equipment and installations are maintained in a safe condition;
all people working with electricity are competent to do the job. Complicated
tasks (i.e. equipment repairs, alterations, installation work and testing) may
require a suitably qualified electrician;
all staff are aware of your organisation’s electrical safety arrangements;
all work activities are to be carried out so as not to give rise to danger;
equipment and procedures are safe and suitable for the working
equipment is switched off and/or unplugged before making adjustments.
‘Live working’ must be eliminated from work practices.
Electricity is recognised as a major hazard for not only can it kill (research
has shown that the majority of electric shock fatalities occur at voltages up to
230 V), but it can cause fires and explosions. Even non-fatal shocks can cause
are used to impose health and safety requirements for electricity used at work.
While the majority of the Regulations concern hardware requirements,
others are more generalised. For example:
Installations shall be of proper construction.
In brief, the Regulations concern the following:
constructed to prevent, so far as is
reasonably practicable, danger.
No electrical equipment is to be used where
its strength and capability may be exceeded
so as to give rise to danger.
Adverse or
Electrical equipment sited in adverse or
hazardous environments must be suitable
and placing of
Permanent safeguarding or suitable
positioning of live conductors is required.
Earthing and other
Equipment must be earthed or other
suitable precautions must be taken (e.g.
the use of residual current devices, double
insulated equipment, reduced voltage
Nothing is to be placed in an earthed
circuit conductor which might, without
suitable precautions, give rise to danger
by breaking the electrical continuity or by
All joints and connections in systems
must be mechanically and electrical
Suitable protective devices should be
installed in each system to ensure all parts
of the system and users of the system are
safeguarded from the effects of fault conditions.
Means of cutting off
the supply and for
on equipment made
to prevent electrical equipment,
which has been made dead in order
to prevent danger, from becoming
live – while any work is carried out.
No work can be carried out on live electrical Regulation 14
equipment unless this can be properly
justified, which means that risk assessments
Adequate working space, adequate means
of access and adequate
lighting shall be provided at all electrical
equipment on which or near which work is
being done in circumstances that may give
rise to danger.
requires technical knowledge or experience
to prevent danger or injury, unless he has
that knowledge or experience, or is under
Health and Safety Executive Local Authorities Enforcement Liaison Committee
Tel: 020 7717 6441
Fax: 020 7717 6418
HSE Infoline – 0845 345 0055 (a ‘one-stop’ shop, providing rapid access to
expert advice and guidance)
e-mail: LAU.enquiries@hse.gsi.gov.uk
Or to download a copy of the Electricity at Work Regulations 1989 (Statutory
www.opsi.gov.uk/si/si1989/Uksi_19890635_en_1.htm
Figure 1.5 The Fire Precautions (Workplace) Regulations 1997
Precautions (Workplace) (Amendment) Regulations 1999) stipulate that:
Any hotel or boarding house provided sleeping accommodation
for more than six persons (guests or staff) or where this sleeping
requires a Fire Certificate.
the means of escape;
other means for ensuring that the means of escape can be safely and effectively used at all material times;
means of fighting fire;
Regulations 1999 (Statutory Instrument 1999 No. 1877) visit www.opsi.gov.
uk/si/si1999/19991877.htm or for a copy of the Act, use the following link:
http://www.fire.org.uk/si/amd1840.htm
Figure 1.6 The Health and Safety at Work Act 1974
18 Wiring Regulations in Brief
Any company with more than 5 employees is legally obliged to possess a
Over the years, the IEE Wiring Regulations have been regularly used by
HSE in their guidance and installation notices, and installations which conform to BS 7671 (as amended) are regarded by HSE as likely to achieve conformity with the relevant parts of the Electricity at Work Regulations 1989.
In certain instances where the Regulations have been used they may also be
accompanied by Codes of Practice approved under Section 16 of the Health
and Safety at Work Act 1974.
Although some existing installations may have been designed and installed
to conform to the Standards set by earlier editions of the Wiring Regulations,
this does not necessarily mean that they will fail to achieve conformity with
the relevant parts of the Electricity at Work Regulations 1989.
For further information about the Health and Safety at Work Act 1974 visit
Although the IEE Wiring Regulations rely (primarily) on British Standards
for their implementation (see Reference section for details) they do, however,
comply with the Statutory Regulations.
Building generally (subject
to certain exemptions)
Building Regulations 2000 (as amended) (for England
SI 2000 No 2531
Building (Scotland) Regulations 2004 (as amended)
Scottish SI 2004 No 406
Building Regulations (Northern Ireland) 2000 (as
Statutory Rule 2000 No 38
amended under the Cinematograph Act, 1909, and/or
Cinematograph Act, 1952)
Distributors’ installations
generally (subject to certain
SI 2006 No 1521
in Scotland – The Civic Government (Scotland) Act
Theatres and other places
licensed for public
SI 1996 No 192
SI 1999 No 2024
The Electricity at Work Regulations (Northern
Ireland) 1991
Statutory Rule No 13
is now available from the Office of Public Sector Information (OPSI) via their
website: www.hmso.gov.uk/stat.htm
Legislation section: http://www.opsi.gov.uk/legislation/wales/w-stat.htm
The series of Scottish Statutory Instruments have been published via the
Scottish Legislation: http://www.opsi.gov.uk/legislation/scotland/s-stat.htm
As well as British Standards, the Wiring Regulations also take account of the
technical substance of agreements reached in CENELEC. In particular:
Application of measures for protection against
Earthing arrangements, protective conductors and
Fundamental principles, assessment of general
Protection against fire where particular risks or
danger exist
Selection and erection of equipment – common rules
Temporary electrical installations for structures,
HD 384.4.473 Al:1980
HD 384.7.708:2005
prHD 60364-5-54:2004
prHD 60364-7-721:2007
HD 384.7.711:2003
prHD 60364-:2007
HD 384.6.61 S2:2003
prHD 60364-7-709:2007
HD 384.7.714 51:2000
HD 384.4.41 S2/Al:2002
HD 384.4.482 51:1997
HD 384.4.43 S2:2001
HD 384.4.42 S1 A2:1994
HD 384.7.703:2005
prHD 60364-5-51:2003
prHD 60364-7-740:2006
Listed by Directive
Selection and erection of equipment – common
BS 7671 will continue to be amended from time to time to take account of the
publication of new or amended CENELEC standards.
By Act of Parliament, the Secretary of State is responsible for ensuring that
the health, welfare and convenience of persons living in or working in (or
one of its prime purposes is to assist in the conservation of fuel and power,
and to prevent waste, undue consumption, and the misuse and contamination
The current legislation in England and Wales is the Building Regulations
2000 (Statutory Instrument No 2531), which is made by the Secretary of
State for the Environment under powers delegated by Parliament under the
They are a set of minimum requirements and basic performance standards designed to secure the health, safety and welfare of people in and around
buildings and to conserve fuel and energy in England and Wales.
The Building Regulations are supported by a series of separate documents
which correspond to the different areas covered by the Regulations. These are
called ‘Approved Documents’ and they contain practical and technical guidance on ways in which the requirements of Schedule 1 and Regulation 7 of
the Building Act 1984 can be met.
Each Approved Document reproduces the actual requirements contained
in the Building Regulations relevant to the subject area. This is then followed
by practical and technical guidance (together with examples) showing how
the requirements can be met in some of the more common building situations.
There may, however, be alternative ways of complying with the requirements
to those shown in the Approved Documents and you are, therefore, under no
obligation to adopt any particular solution in an Approved Document if you
prefer to meet the requirement(s) in some other way.
2.4 What about the rest of the United
Table 2.1 Building Regulations
‘Deemed to
Satisfy’ by meeting
(Scotland) Act 2003, and the Building (Scotland) Regulations 2004 then set
the functional standards under this Act. The methods for implementing these
requirements are similar to those for England & Wales, except that the guidance documents (i.e. for achieving compliance) are contained in two Technical
Handbooks, one for domestic work, and one for non-domestic. Each handbook has a general section, which is then followed by 6 technical sections.
The main procedural difference between the Scottish system and the others is that a building warrant is still required before work can start in Scotland
and certain facilities in dwellings are still required in Section 3 of the domestic technical handbook.
On the other hand, Building Regulations (Northern Ireland) Order 1979
(as amended by the Planning and Building Regulations (Amendment) (NI)
Order 1990) is the main legislation for Northern Ireland and the Building
Regulations (Northern Ireland) 2000 then details the requirements for meeting this legislation.
or technical booklets published by the Department) are then used to ensure
that the requirements are implemented (i.e. deemed to satisfy).
Preparation of site and
Stairs, ramps and protection
Conservation of fuel and
Access for facilities and
For many years, the UK has managed to maintain relatively high electrical
safety standards with the support of voluntary controls based on BS 7671, but
with a growing number of electrical accidents occurring in the ‘home’, the
government has been forced to consider the legal requirement for safety in
electrical installation work in dwellings.
domestic accommodation) have had to be designed and installed in accordance
with the Building Regulations. Part P, which is based on the fundamental principles set out in Chapter 13 of BS 7671:2008 (i.e. the IEE Wiring Regulations). In
addition, all fixed electrical installations (i.e. wiring and appliances fixed to the
building fabric such as socket outlets, switches, consumer units and ceiling fittings) have to be designed, installed, inspected, tested and certified to BS 7671.
Part P also introduced new requirements for cable core colours for a.c. power
circuits and with effect from 31 March 2006, all new installations or alterations
to existing installations must use the new (harmonised) colour cables. (Further
information concerning cable identification colours for extra-low-voltage
and d.c. power circuits is available from the IEE website at www.iee.org/
cablecolours.)
Table 2.3 Identification of conductors in a.c. power and lighting circuits
Phase of single-line circuit
Phase 1 of 3-line circuit
Phase 2 of 3-line circuit
Phase 3 of 3-line circuit
For single-line installations in domestic premises, the new colours are the same
as those for flexible cables to appliances (namely green-and-yellow, blue and
brown for the protective, neutral and line
operate at low voltage or extra-low voltage which are not controlled by the
Electricity Safety, Quality and Continuity Regulations 2002 (as amended) or
the Electricity at Work Regulations 1989 (as amended).
2.5.1 What is the aim of Approved Document P?
design, installation, inspection and testing of electrical installations in dwellings when they (i.e. the installations) are being newly built, extended or altered.
The government is currently introducing a scheme whereby domestic installations shall be checked at regular intervals (as well as when they are sold and/or
purchased) to make sure that they comply. This will mean, of course, that
if you had an installation which was not correctly certified, then your house
insurance might well not be valid!
2.5.2 Who is responsible for electrical safety?
Basically, there are three people who are responsible for the electrical safety
of (and within) buildings. These are:
The owner – needs to determine whether the work carried out is either
minor or notifiable. If the work is notifiable, then the owner needs to make
sure that the person(s) carrying out the work is either registered under one
of the self-certified schemes (see Figure 2.3) or is able to certify their work
under the local authority Building Control Approval route.
The designer – needs to ensure that all electrical work is designed,
constructed, inspected and tested in accordance with BS 7671 (current
issue) and either falls under a Competent Persons Scheme or the local
authority Building Control Approval route.
The builder/developer – needs to ensure that they have electricians who
can self-certify their work or who are qualified/experienced enough to
enable them to sign off under the Electrical Installation Certification form.
2.5.3 What are the statutory requirements?
All electrical installations need to:
be designed and installed to protect against mechanical and thermal damage;
be designed and installed so that they will not present an electrical shock
and/or fire hazard;
be tested and inspected to meet relevant equipment/installation standards;
or alter an electrical installation can do so with reasonable safety;
2.5.3.1 What does all this mean?
With a few exceptions, any electrical work undertaken in a home which
includes the addition of a new electrical circuit, or involves work in the:
must be reported to the local authority Building Control for inspection. This
includes any work undertaken professionally, or by you or another family
member or by a friend.
The ONLY exception is when the installer has been approved by a
Competent Persons organisation such as ELECSA (see Figure 2.3).
Authorised competent persons selfcertification schemes for installers who
can do all electrical installation work
Authorised competent persons selfcertification schemes for installers
who can do electrical work only if it is
necessary when they are carrying out
corgi-group..
Figure 2.3 Authorised competent persons self-certification schemes for
2.5.4 What types of building does Approved Document P
land associated with domestic buildings;
fixed lighting and pond pumps in gardens;
shops and public houses with a flat above;
common access areas in blocks of flats such as corridors and stairways;
Locations where work is being
Extensions and modifications to
Ceiling (overhead) heating
Garden – lighting
Garden – power
*if the installation requires outdoor wiring
2.5.5 What is a competent firm?
who work in conformance with the requirements to BS 7671;
whose standard of electrical work has been assessed by a third party;
who are registered under the NICEIC Approved Contractor scheme and
the Electrotechnical Assessment Scheme.
2.5.6 What is a competent person responsible for?
When a competent person undertakes installation work, that person is responsible for:
ensuring compliance with BS 7671: 2001 and all relevant Building
self-certification certificate;
providing the person ordering the work with a completed Electrical
2.5.7 Who is entitled to self-certify an installation?
Part P affects every electrical contractor carrying out fixed installation and/or
alteration work in homes. Only registered installers are entitled to self-certify
the electrical work, however, and they must be registered as a competent person under one of the schemes shown in