IEC_TS_62257-5-2005.pdf

TECHNICAL SPECIFICATION IEC TS 62257-5 First edition2005-07 Recommendations for small renewable energy and hybrid systems for rural electrification Part 5:Protection against electrical hazards Reference number IEC/TS 62257-5:2005(E)LICENSED TO MECON Limited.-RANCHI/BANGALOREFOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.Publication numbering As from 1 January 1997 all IEC publications are issued with a designation in the 60000 series.For example,IEC 34-1 is now referred to as IEC 60034-1.Consolidated editions The IEC is now publishing consolidated versions of its publications.For example,edition numbers 1.0,1.1 and 1.2 refer,respectively,to the base publication,the base publication incorporating amendment 1 and the base publication incorporating amendments 1 and 2.Further information on IEC publications The technical content of IEC publications is kept under constant review by the IEC,thus ensuring that the content reflects current technology.Information relating to this publication,including its validity,is available in the IEC Catalogue of publications(see below)in addition to new editions,amendments and corrigenda.Information on the subjects under consideration and work in progress undertaken by the technical committee which has prepared this publication,as well as the list of publications issued,is also available from the following:IEC Web Site(www.iec.ch)Catalogue of IEC publications The on-line catalogue on the IEC web site(www.iec.ch/searchpub)enables you to search by a variety of criteria including text searches,technical committees and date of publication.On-line information is also available on recently issued publications,withdrawn and replaced publications,as well as corrigenda.IEC Just Published This summary of recently issued publications(www.iec.ch/online_news/justpub)is also available by email.Please contact the Customer Service Centre(see below)for further information.Customer Service Centre If you have any questions regarding this publication or need further assistance,please contact the Customer Service Centre:Email:custserviec.ch Tel:+41 22 919 02 11 Fax:+41 22 919 03 00 LICENSED TO MECON Limited.-RANCHI/BANGALOREFOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.TECHNICAL SPECIFICATION IECTS 62257-5 First edition2005-07 Recommendations for small renewable energy and hybrid systems for rural electrification Part 5:Protection against electrical hazards PRICE CODE IEC 2005 Copyright-all rights reserved No part of this publication may be reproduced or utilized in any form or by any means,electronic or mechanical,including photocopying and microfilm,without permission in writing from the publisher.International Electrotechnical Commission,3,rue de Varemb,PO Box 131,CH-1211 Geneva 20,SwitzerlandTelephone:+41 22 919 02 11 Telefax:+41 22 919 03 00 E-mail:inmailiec.ch Web:www.iec.ch V For price,see current catalogueCommission Electrotechnique InternationaleInternational Electrotechnical Commission LICENSED TO MECON Limited.-RANCHI/BANGALOREFOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.2 TS 62257-5 IEC:2005(E)CONTENTS FOREWORD.4 INTRODUCTION.6 1 Scope.7 2 Normative references.8 3 Terms and definitions.9 4 Classification of decentralised rural electrification systems.9 5 Protection against electric shock.10 5.1 General.10 5.2 Requirements on the d.c.side of a DRES.10 5.3 Requirements on the a.c.side of a DRES.10 6 Protection against overcurrent.11 6.1 General.11 6.2 Protection against overload currents.11 6.3 Protection against short-circuits.11 7 Protection against risk of fire.12 8 Protection against effects of lightning.12 8.1 Principle.12 8.2 Provisions for lightning protection of DRES.12 9 Selection and erection of electrical equipment.13 9.1 General.13 9.2 Operational conditions and external influences.13 9.3 Wiring system.14 9.4 Isolation and switching.14 9.5 Surge protective devices.16 9.6 Earthing arrangement,protective conductors and protective bonding conductors.16 10 Verification.17 11 Operation and maintenance.17 Annex A(informative)Protection against electric shock in electrical installations(for complete information,see IEC 61140 and IEC 60364-4-41).18 Annex B(informative)Types of LV distribution systems earthing.22 Annex C(informative)Classification of electrical equipment.29 Annex D(informative)General information concerning protection against lightning.32 Bibliography.34 Figure B.1 TN-S system.23 Figure B.2 TN-C-S system.23 Figure B.3 TN-C system.23 Figure B.4 TT system.24 Figure B.5 TN-S d.c.system.25 Figure B.6 TN-C d.c.system.26 Figure B.7 TN-C-S d.c.system.27 LICENSED TO MECON Limited.-RANCHI/BANGALOREFOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.TS 62257-5 IEC:2005(E)3 Figure B.8 TT d.c.system.28 Figure D.1 Example of effects of a lightning stroke.32 Table 1 Typology of decentralized electrification systems.9 Table 2 Rated operating residual current of the protective device depending o