IEC_60364-4-43_64_1347_CD.pdf

64/1347/CDCOMMITTEE DRAFT(CD)IEC/TC or SC:TC 64Project numberIEC 60364-4-43,Ed.3Title of TC/SC:Electrical installations and protection againstelectrical shockDate of circulation2003-10-24Closing date for comments2004-01-30Also of interest to the following committees Supersedes document64/1289/MCRFunctions concerned:Safety EMC Environment Quality assuranceSecretary:Mr.R.Pelta(Germany)E-mail:THIS DOCUMENT IS STILL UNDER STUDY AND SUBJECT TOCHANGE.IT SHOULD NOT BE USED FOR REFERENCE PURPOSES.RECIPIENTS OF THIS DOCUMENT ARE INVITED TO SUBMIT,WITHTHEIR COMMENTS,NOTIFICATION OF ANY RELEVANT PATENTRIGHTS OF WHICH THEY ARE AWARE AND TO PROVIDESUPPORTING DOCUMENTATION.Title:IEC 60364-4-43,Ed.3:Electrical installations of buildings-Part 4-43:Protection for safety-Protection against overcurrent(Titre):Introductory noteThis document has been prepared by TC 64/WG 2.FORM CD(IEC)2002-05-14Copyright 2003 International Electrotechnical Commission,IEC.All rights reserved.It ispermitted to download this electronic file,to make a copy and to print out the content for the solepurpose of preparing National Committee positions.You may not copy or mirror the file orprinted version of the document,or any part of it,for any other purpose without permission inwriting from IEC.XXX IEC:200X 2 64/1347/CDELECTRICAL INSTALLATIONS OF BUILDINGS Part 4-43:Protection for safety Protection against overcurrent430Introduction430.1(431)1 ScopePart 4-43 of IEC 60364 describes how live conductors are protected by one or more devices forautomatic interruption of the supply in the event of overload(see clause 433)and short-circuits(seeclause 434)except in cases where the overcurrent is limited in accordance with clause 436 or bythe conditions described in 433.4,443.5 or 443.3 are met.Further,protection against overload andagainst short-circuits shall be co-ordinated in accordance with clause 436.NOTE 1 Live conductors protected against overload in accordance with clause 434 are considered to be protected alsoagainst faults likely to cause overcurrents of a magnitude similar to overload currents.NOTE 2 The requirements of this standard do not take account of external influences.For the application of protectivemeasures in relation to conditions of external influences,see 410.3.4 of IEC 60364-4-41 and clause 422 of IEC 60364-4-42.NOTE 3 Protection of conductors according to this standard does not necessarily protect the equipment connected to theconductors.(433.1 and 434.1)1Protective devices shall be provided to break any overcurrent flowing in the circuit conductors beforesuch a current could cause a danger due to thermal and mechanical effects or a temperature risedetrimental to insulation,joints,terminations,or surroundings of the conductors.430.2Normative referencesThe following normative documents contain provisions which,through reference in this text,constitute provisions of this part of IEC 60364.For dated references,subsequent amendments to,or revisions of,any of these publications do not apply.However,parties to agreements based onthis part of IEC 60364 are encouraged to investigate the possibility of applying the most recenteditions of the normative documents indicated below.For undated references,the latest edition ofthe normative document referred to applies.Members of IEC and ISO maintain registers of currentlyvalid International Standards.IEC 60269-1:1998,Low-voltage fuses Part 1:General requirementsIEC 60269-2:1986,Low-voltage fuses Part 2:Supplementary requirements for fuses for use byauthorized persons(fuses mainly for industrial application)IEC 60269-3:1987,Low-voltage fuses Part 3:Supplementary requirements for fuses used byunskilled persons(fuses mainly for household and similar applications)IEC 60364-4-41:Electrical installations of buildings Part 4-41:Protection for safety Protectionagainst electric shockIEC 60364-5-52:Electrical installations of buildings Part 5-52:Selection and erection of electricalequipment Wiring systems1 In this standard,references in brackets refer to the previous numbering system.XXX IEC:200X 3 64/1347/CDIEC 60724:1984,Guide to the short-circuit temperature limits of electric cables with a rated voltagenot exceeding 0,6/1,0 kVIEC 60898:1995,Electrical accessories Circuit-breakers for overcurrent protection for householdand similar installationsIEC 60947-1:1999,Low-voltage switchgear and controlgear Part 1:General rulesIEC 60947-2:1995,Low-voltage switchgear and controlgear Part 2:Circuit-breakersIEC 60947-4-1:1990,Low-voltage switchgear and controlgear Part 4-1:Contactors and motor-starters Electromechanical contactors and motor-startersIEC 61009(all parts),Residual current operated circuit-breakers with integral overcurrent protectionfor household and similar uses(RCBOs)431(473.3)Requirements according to the nature of the circuits431.1(473.3.1)Protection of phase conductors431.1.1(473.3.1.1)Detection of overcurrent shall be provided for all phase conductors;it shallcause the disconnection of the conduc