Electrical Installation Calculations For Compliance with BS 7671:2008

著者 Mark Coates. この書籍の出版社はこちらです John Wiley & Sons.

Mark Coates ERA Technology Brian Jenkins Institution of Electrical Engineers Manual calculations are still extensively used and in particular are necessary for checking and verifying various Software calculation design packages. It is highly recommended that users of such software familiarise themselves with the rudiments of these calculations prior to using the software packages.

This essential book fills the gap between software and manual calculations. It provides the reader with all the necessary tools to enable accurate calculations of Circuit designs. Rather than complex equations, this book uses extensive worked examples to make understanding the calculations simpler. The focus on worked examples furnishes the reader with the Knowledge to carry out the necessary checks to electrical cable sizing software programmes.

Other key features include:

Updated information on 230 volt references and voltage drop under normal load conditions
New sections on buried cables that take into account Soil Thermal conductivity, trenches and grouping, allowing readers to carry out accurate cables sizing
Information and examples of Steel wired armour cables, new to this edition. This includes sufficiency during short circuits and, for cables with externally run CPCs, gives unique fault conditions.
Covers calculations of cross-sectional areas of circuit live conductors
Earth fault loop impedances
Protective conductor cross-sectional areas and short circuit conditions
Short circuit protection.


The last chapter combines all of the calculations of the previous chapters to enable the reader to complete an accurate design of an installation circuit under all conditions.

A unique tool for detailed electrical installation trade, Electrical Installation Calculations, Fourth Edition is invaluable to electricians, electrical designers, installers, technicians, contractors, and Plant engineers. Senior electrical Engineering students and Technical colleges, junior engineers, and contracts managers will also find this text useful.

Mark Coates ERA Technology Brian Jenkins Institution of Electrical Engineers About the Authors

Preface

Acknowledgements

Symbols

Definitions

1 Calculation of the Cross-sectional Areas of Circuit Live Conductors

General circuits

Circuits in thermally insulating Walls

Circuits totally surrounded by thermally insulating material

Circuits in varying External influences and installation conditions

Circuits in ventilated trenches

Circuits using mineral-insulated cables

Circuits on perforated Metal cable trays

Circuits in enclosed trenches

Circuits buried in the ground

Grouped circuits not liable to simultaneous overload

Circuits in low ambient temperatures

Grouped ring circuits

Motor circuits subject to frequent stopping and starting

Circuits for star-delta starting of motors

Change of parameters of already installed circuits

Admixtures of cable sizes in enclosures

Grouping of cables having different insulation

2 Calculation of Voltage Drop Under Normal Load Conditions

The simple approach

The more accurate approach taking account of conductor operating Temperature

The more accurate approach taking account of load power Factor

The more accurate approach taking account of both conductor operating temperature and load power factor

Voltage drop in ring circuits

Voltage drop in ELV circuits

3 Calculation of Earth Fault Loop Impedance

The simple approach

The more accurate approach taking account of conductor temperature

Calculations taking account of transformer impedance

Calculations concerning circuits fed from sub-distribution boards

Calculations where conduit or trunking is used as the protective conductor

Calculations where cable armouring is used as the protective conductor

4 Calculations Concerning Protective Conductor Cross-sectional Areas

Calculations when the protective device is a fuse

Calculations when the protective device is an mcb

Calculations when the protective device is an rccb

5 Calculations Related to Short Circuit Conditions

A. C. single-phase circuits

The more rigorous method for A.C. single-phase circuits

A.C. three-phase circuits

6 Combined Examples

Appendix The Touch Voltage Concept

Index