IEC_64-1408e.pdf

64/1408/CDCOMMITTEE DRAFT(CD)IEC/TC or SC:TC 64 Project number IEC 60364-4-43,Ed.3 Title of TC/SC:Electrical installations and protection against electrical shock Date of circulation 2004-09-03 Closing date for comments 2004-12-03 Also of interest to the following committees Supersedes documents 64/1347/CD 64/1407/CC Functions concerned:Safety EMC Environment Quality assurance Secretary:Mr.R.Pelta(Germany)E-mail: THIS DOCUMENT IS STILL UNDER STUDY AND SUBJECT TO CHANGE.IT SHOULD NOT BE USED FOR REFERENCE PURPOSES.RECIPIENTS OF THIS DOCUMENT ARE INVITED TO SUBMIT,WITH THEIR COMMENTS,NOTIFICATION OF ANY RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE AND TO PROVIDE SUPPORTING DOCUMENTATION.Title:IEC 60364-4-43,Ed.3:Electrical installations of buildings-Part 4-43:Protection for safety-Protection against overcurrent (Titre):Introductory note This document has been prepared by TC 64/MT 2 FORM CD(IEC)2002-05-14 Copyright 2004 International Electrotechnical Commission,IEC.All rights reserved.It is permitted to download this electronic file,to make a copy and to print out the content for the sole purpose of preparing National Committee positions.You may not copy or mirror the file or printed version of the document,or any part of it,for any other purpose without permission in writing from IEC.60364-4-43 Ed.3/CD IEC:200X 2 64/1408/CD ELECTRICAL INSTALLATIONS OF BUILDINGS Part 4-43:Protection for safety Protection against overcurrent 430 Introduction 430.1(431)1 Scope Part 4-43 of IEC 60364 describes how live conductors are protected by one or more devices for automatic interruption of the supply in the event of overload(see clause 433)and short-circuits(see clause 434)except in cases where the overcurrent is limited in accordance with clause 436 or by the conditions described in 433.3,433.5 or 434.3 are met.Further,protection against overload and against short-circuits shall be co-ordinated in accordance with clause 435.NOTE 1 Live conductors protected against overload in accordance with clause 433 are considered to be protected also against 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 protective measures 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 the conductors.NOTE 4 Flexible cables connecting equipment by plugs and socket-outlet to fixed installations are not in the scope of this part and for this reason are not necessarily protected against overcurrent.430.2 Normative references The 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 on this part of IEC 60364 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below.For undated references,the latest edition of the normative document referred to applies.Members of IEC and ISO maintain registers of currently valid International Standards.IEC 60269-1:Low-voltage fuses Part 1:General requirements IEC 60269-2:Low-voltage fuses Part 2:Supplementary requirements for fuses for use by authorized persons(fuses mainly for industrial application)IEC 60269-3:Low-voltage fuses Part 3:Supplementary requirements for fuses used by unskilled persons(fuses mainly for household and similar applications)IEC 60364-4-41:Electrical installations of buildings Part 4-41:Protection for safety Protection against electric shock IEC 60364-5-52:Electrical installations of buildings Part 5-52:Selection and erection of electrical equipment Wiring systems 1 In this standard,references in brackets refer to the previous numbering system.60364-4-43 Ed.3/CD IEC:200X 3 64/1408/CD IEC 60724:Guide to the short-circuit temperature limits of electric cables with a rated voltage not exceeding 0,6/1,0 kV IEC 60898:Electrical accessories Circuit-breakers for overcurrent protection for household and similar installations IEC 60947-1:Low-voltage switchgear and controlgear Part 1:General rules IEC 60947-2:Low-voltage switchgear and controlgear Part 2:Circuit-breakers IEC 60947-4-1:Low-voltage switchgear and controlgear Part 4-1:Contactors and motor-starters Electromechanical contactors and motor-starters IEC 61009(all parts),Residual current operated circuit-breakers with integral overcurrent protection for household and similar uses(RCBOs)430.3 General requirement(433.1 and 434.1)1 Protective devices shall be provided to break any overcurrent flowing in the circuit conductors before such a current could cause a danger due to thermal and mechanical effects or a temperature rise detrimental to insulation,joint