Electrical Installation Calculations
For Compliance with BS 7671:2008
4th Edition
Published on 28. July 2010
216 pages
978-1-4443-2428-0 (ISBN)
Description
Manual calculations are still extensively used and in particularare necessary for checking and verifying various softwarecalculation design packages. It is highly recommended that users ofsuch software familiarise themselves with the rudiments of thesecalculations prior to using the software packages.
This essential book fills the gap between software and manualcalculations. It provides the reader with all the necessary toolsto enable accurate calculations of circuit designs. Rather thancomplex equations, this book uses extensive worked examples to makeunderstanding the calculations simpler. The focus on workedexamples furnishes the reader with the knowledge to carry out thenecessary checks to electrical cable sizing softwareprogrammes.
Other key features include:
* Updated information on 230 volt references and voltage dropunder normal load conditions
* New sections on buried cables that take into account soilthermal conductivity, trenches and grouping, allowing readers tocarry out accurate cables sizing
* Information and examples of steel wired armour cables, new tothis edition. This includes sufficiency during short circuits and,for cables with externally run CPCs, gives unique faultconditions.
* Covers calculations of cross-sectional areas of circuit liveconductors
* Earth fault loop impedances
* Protective conductor cross-sectional areas and short circuitconditions
* Short circuit protection.
The last chapter combines all of the calculations of theprevious chapters to enable the reader to complete an accuratedesign of an installation circuit under all conditions.
A unique tool for detailed electrical installation trade,Electrical Installation Calculations, Fourth Edition isinvaluable to electricians, electrical designers, installers,technicians, contractors, and plant engineers. Senior electricalengineering students and technical colleges, junior engineers, andcontracts managers will also find this text useful.
Reviews / Votes
"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." (Broadcastnewsroom, 20 October 2010).More details
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Book
06/2010
4th Edition
Wiley
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06/2010
Wiley-Blackwell
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Persons
Professor Mark Coates, ERA Technology Ltd, Surrey, UK
Professor Coates is an internationally renowned expert on current ratings for high and low voltage cable systems. He joined ERA Technology in 1983 and is currently Head of Cables at ERA's Engineering Consultancy business. His areas of expertise include measurement of the thermal properties of cable materials, calculation of heat flow through complex thermal paths, MV partial discharge, breakdown testing and life prediction using statistical analysis. He has been one of the leading contributors to the work of IEC Technical Committee 20 (Electric Cables).
Professor Coates is an active member of the IEE/BSI Committee concerned with electrical installations, BS7671. Before joining ERA, he spent several years as a plant engineer in the chemical and textile industry.
Mr Brian D. Jenkins, (deceased), formerly British Standards Institution
Content
About the Authors.
Preface.
Acknowledgements.
Symbols.
Definitions.
1 Calculation of the cross-sectional areas of circuit liveconductors.
General circuits.
Circuits in thermally insulating walls.
Circuits totally surrounded by thermally insulatingmaterial.
Circuits in varying external influences and installationconditions.
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 loadconditions.
The simple approach.
The more accurate approach taking account of conductor operatingtemperature.
The more accurate approach taking account of load powerfactor.
The more accurate approach taking account of both conductoroperating 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 conductortemperature.
Calculations taking account of transformer impedance.
Calculations concerning circuits fed from sub-distributionboards.
Calculations where conduit or trunking is used as the protectiveconductor.
Calculations where cable armouring is used as the protectiveconductor.
4 Calculations concerning protective conductorcross-sectional areas.
Calculations when the protective device is a fuse.
Calculations when an external cpc is in parallel with thearmour.
Calculations when the protective device is an mcb.
Calculations when the protective device is an RCD or RCBO.
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.
