Modern Wiring Practice

W E Steward, T A Stubbs, R. A. Beck, W.E. Steward

• Publisher: Routledge
• Year: 2012
• eBook ISBN: 9781136346347
• Topic: Technology & Engineering
• Subtopic: Civil Engineering
• Index: Technology & Engineering

Continuously in print since 1952, Modern Wiring Practice has now been fully revised to provide an up-to-date source of reference to building services design and installation in the 21st century. This compact and practical guide addresses wiring systems design and electrical installation together in one volume, creating a comprehensive overview of the whole process for contractors and architects, as well as electricians and other installation engineers. Best practice is incorporated throughout, combining theory and practice with clear and accessible explanation, all within the framework of the Wiring Regulations.

Introducing the fundamentals of design and installation with a minimum of mathematics, this book is also relevant reading for all students of electrical installation courses, such as the 2330 Certificate in Electrotechnical Technology, and NVQs from City & Guilds (including 2356, 2391 and 2382 awards), as well as trainees in industry undertaking Apprenticeships and Advanced Apprenticeships.

This new edition incorporates the latest thinking on sustainability and the environment and is fully up-to-date with the 17th Edition of the IEE Wiring Regulations. Illustrations have been completely updated to show current best practice and are now in full colour.

Reviews of a previous edition:

'This book has long been a favourite of mine. Its regular updating by the issue of new editions ensures it is always completely up to date with the requirements of electrical installation. It is a book that I would thoroughly recommend to any person with an involvement in our industry for it is without doubt one of the very best available, written in a clear and readily understandable manner.'

Electrical Contractor

'Refreshingly practical. This book will prove useful to anyone involved in the design and installation of electrical systems: from the apprentice to the architect.'

Electrical Review

Part I

Design of Electrical Installation Systems

Chapter 1

Regulations Governing Electrical Installations

Whatever type of electrical equipment is installed, it has to be connected by means of cables and other types of conductors, and controlled by suitable switchgear. This is the work which is undertaken by the installation engineer, and no equipment, however simple or elaborate, can be used with safety unless the installation has been planned, correctly designed and the installation work has been carried out correctly.

1.1 PLANNING OF INSTALLATION WORK

Like fire, electricity is a very good servant, but if not properly controlled and used it can prove to be a very dangerous master. The need for planned methods of wiring and installation work has long been recognised and all kinds of regulations, requirements, recommendations, codes of practice and so on have been issued. Some are mandatory and can be enforced by law, whilst others are recommendations.

This book deals with the work of the electrical designer and installation engineer and an attempt will be made to present, as clearly as possible, a general outline of the basis of good installation work, including design, planning and execution. References will be made to the various rules and regulations, and copies of these must be obtained and studied.

From what has already been said it should be clear to everyone who intends to undertake any electrical installation work that they must be conversant with all of the recognised standards and practices.

If an uninstructed amateur attempts to paint his house, at the very worst he can make an unsightly mess, but if he decides to install a few additional ‘points’ in his house, his workmanship might become a positive danger to himself and his family.

When planning an installation there are many things which must be taken into account: the correct size of cables, suitable switchgear, current rating of overcurrent devices, the number of outlets which may be connected to a circuit and so on. These and other matters are explained in the various chapters of this book.

The regulations governing electrical design and installation work can be divided into two categories: statutory regulations and non-statutory regulations (Fig. 1.1).

Figure 1.1 Regulations. It is essential before designing or installing electrical equipment to obtain and study copies of the relevant British Standards, Regulations and other guidance documents. A selection of these is illustrated here.

Statutory regulations include:

Type of installation/ activity	Regulation	Administered by
Installations in general (with certain exceptions)	Electricity Safety, Quality and Continuity Regulations 2002 and amendments	Secretary of State
All installations in the workplace including factories and offices	Electricity at Work Regulations 1989 and amendments	Health and Safety Executive
Management and design of installations	Construction (Design and management) Regulations 2007	Secretary of State
Installation practice	Work at Height Regulations 2005	Secretary of State
Electrical equipment	The Low Voltage Equipment (Safety) Regulations 1989	Secretary of State
Buildings in general with certain exceptions (Separate Regulations apply in Scotland and N Ireland)	Building Regulations 2000 and amendments	Department for Communities and Local Government

Non-statutory regulations include:

Type of installation	Regulation	Published by
Installations in general (with certain exceptions)	Requirements for Electrical Installations. IEE Wiring Regulations Seventeenth Edition BS 7671: 2008	British Standards Institution and the Institution of Engineering and Technology
Installations on construction sites	BS 7375: 1996	British Standards Institution
Conduit systems	BS EN 61386: 2004	British Standards Institution
Trunking and ducting systems	BS EN 50085	British Standards Institution
Accommodation of building services in ducts	BS 8313: 1997	British Standards Institution
Installations in explosive atmospheres	BS EN 60079: 2003	British Standards Institution
Emergency lighting of premises (other than cinemas and similar premises)	BS 5266: 1999	British Standards Institution
Fire detection and alarm systems in buildings	BS 5839: 2002	British Standards Institution
Protection of structures against lightning	BS EN 62305: 2006	British Standards Institution
Industrial plugs, sockets and couplers	BS EN 60309: 1999	British Standards Institution
Uninterruptible power supplies	BS EN 62040	British Standards Institution
Earthing	BS 7430: 1998	British Standards Institution

1.2 THE ELECTRICITY SAFETY, QUALITY AND CONTINUITY REGULATIONS 2002

The Electricity Safety, Quality and Continuity Regulations 2002 came into effect on 31 January 2003 and were drawn up with the object of securing a proper supply of electrical energy and the safety of the public. An amendment, effective from October 2006, introduced a number of changes. The regulations replace The Electricity Supply Regulations 1988 and subsequent amendments up to and including those issued in 1998.

The Regulations apply to all ‘duty holders’ concerned with the supply and use of electrical energy and these include generators, distributors, transmitters, meter operators and others supplying electricity to consumers. They also apply to the agents, contractors and subcontractors of any duty holders.

As with the earlier regulations, parts of the 2002 regulations apply to the supply of electricity to consumer’s installations (Regulations 23–29 inclusive) and give the electricity distributor powers to require certain standards of installation before giving or maintaining a supply to the consumer. Regulation 25(2) states that ‘A distributor shall not give his consent to the making or altering of the connection where he has reasonable grounds for believing that the consumer’s installation fails to comply with British Standard Requirements.’

If any installation is not up to the standard, the distributor may issue a notice in writing to the consumer requiring remedial works to be carried out within a reasonable period. The period required must be stated in the notice. If remedial works are not carried out by the end of the period specified, the distributor may disconnect (or refuse to connect) the supply and, in the event of such disconnection must set out the reasons in a further written notice.

A distributor may also disconnect a supply without giving notice, if such disconnection can be justified on the grounds of safety. In this event the distributor must give notice in writing as soon as reasonably practicable, giving reasons and details of remedial measures required. The distributor shall restore the supply when the stipulated remedial measures have been taken.

If there is a dispute between the distributor and consumer over the disconnection or refusal to connect, which cannot be resolved between them, the matter may be referred to the Secretary of State who shall appoint a suitably qualified person to determine the dispute. Following the determination, the distributor shall maintain, connect, restore or may disconnect the supply as appropriate, subject to any conditions specified in the determination.

1.3 IEE WIRING REGULATIONS – BS 7671

The full title is ‘Requirements for electrical installations – The IEE Wiring Regulations – Seventeenth Edition. BS 7671: 2008, and is based upon CENELEC (The European Committee for Electrotechnical Standardisation) Harmonisation Documents formed from IEC (International Electrotechnical Commission) standards. The requirements and some of the actual wordings are therefore similar to IEC standards.

The IEE Regulations are divided into the following parts:

Part 1 Scope, object and fundamental principles

Part 2 Definitions

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

There are also 15 appendices, and these are:

Appendix 1	British standards to which reference is made in the Regulations
Appendix 2	Statutory regulations and associated memoranda
Appendix 3	Time/current characteristics of overcurrent protective devices and residual current devices (RCDs)
Appendix 4	Current-carrying capacity and voltage drop for cables and flexible cords. Tables are included for cables with copper or aluminium conductors
Appendix 5	Classification of external influences
Appendix 6	Model forms for certification and reporting
Appendix 7	Harmonised cable core colours
Appendix 8	Current-carrying capacity and voltage drop for busbar trunking and powertrack systems
Appendix 9	Definitions – multiple source, d.c. and other systems
Appendix 10	Protection of conductors in parallel against overcurrent
Appendix 11	Effect of harmonic currents on balanced 3-phase systems
Appendix 12	Voltage drop in consumers’ installations
Appendix 13	Methods for measuring the insulation resistance/impedance of floors and walls to Earth or to the protective conductor system
Appendix 14	Measurement of earth fault loop impedance: consideration of the increase of the resistance of conductors with increase of temperature
Appendix 15	Ring and radial final circuit arrangements, Regulation 433.1

In addition to the Regulations themselves, the IEE also publish books of Guidance Notes and these include on-site and design guides.

The guides provide much additional useful information over and above that contained in the 17th edition of the Wiring Regulations themselves.

This present book is based upon the requirements of the 17th edition of the IEE Regulations, and the following comments on each part are offer...

Table of contents

• Cover
• Halftitle
• Title
• Copyright
• Contents
• Preface
• Acknowledgements
• Modern Wiring Practice – W.E. Steward
• PART I. Design of Electrical Installation Systems
• PART II. Practical Work
• Appendix A. Appendix A – Extracts from IEE Tables
• Appendix B. Glossary of Terms
• Index