IEC_60364-4-46-1981_scan.pdf

C.D.U./U.D.C.:621.316.172.015.024.025.001.25.004-14614.825.001.25COMMISSION ELECTROTECHNIQUE INTERNATIONALENORME DE LA CEIINTERNATIONAL ELECTROTECHNICAL COMMISSIONIEC STANDARDPublication 364-4-47Premiere edition-First edition1981Installations electriques des batimentsQuatrieme partie:Protection pour assurer la securiteChapitre 47:Application des mesures de protection pour assurer la scuritSection 470:GeneralitesSection 471:Mesures de protection contre les chocs lectriquesElectrical installations of buildingsPart 4:Protection for safetyChapter 47:Application of protective measures for safetySection 470:GeneralSection 471:Measures of protection against electric shockMots cles:installations electriques des batiments;Key words:electrical installations of buildings;direct-current and alternating-tensions du courant continu et ducurrent voltages;application ofcourant alternatif;application dessafety requirements;electricalexigences de securite;exigences desafety requirements.securite electrique.Droits de reproduction reserves-Copyright-all rights reservedAucune partie de cette publication ne peut ere reproduite ni utise sous quelque forme No part of this publication may be reproduced or uilized in any form or by any meansque ce soit et par aucun procede,electronique ou mecanique,y compris la photocopie electronic or mechanical,including photocopying and microfim,without permision inet les microfilms,sans Ieccord ecrit de lediteur.writing from the publisher.Bureau Central de la Commission Electrotechnique Internationale1,rue de VarembeGeneve,SuisseIECPrixPrice Fr.s.15.-VOL 12.3-INTERNATIONAL ELECTROTECHNICAL COMMISSIONELECTRICAL INSTALLATIONS OF BUILDINGSPart 4:Protection for safetyChapter 47:Application of protective measures for safetySection 470:GeneralSection 471:Measures of protection against electric shockFOREWORD1)The formal decisions or agreements of the IEC on technical matters,prepared by Technical Committees on which all theNational Committees having a special interest therein are represented,express,as nearly as possible,an internationalconsensus of opinion on the subjects dealt with.2)They have the form of recommendations for international use and they are accepted by the National Committees in thatsense.3)In order to promote international unification,the IEC expresses the wish that all National Committees should adopt thetext of the IEC recommendation for their national rules in so far as national conditions will permit.Any divergencebetween the IEC recommendation and the corresponding national rules should,as far as possible,be clearly indicated inthe latter.PREFACEThis standard has been prepared by IEC Technical Committee No.64,Electrical Installations of Buildings.This standard has been prepared in two steps.A draft of Section 470 was discussed at the meeting held in Sydney in 1979.As a result of this meeting,a draft,Document 64(Central Office)79,was submitted to the National Committees for approval under the Six Months Rule inSeptember 1979.The National Committees of the following countries voted explicitly in favour of publication:ArgentinaAustraliaJapanAustriaKorea(Republic of)BelgiumNetherlandsBulgariaPolandCanadaRomaniaChinaSouth Africa(Republic of)SwedenDenmarkEgyptSwitzerlandFranceTurkeyGermanyUnion of SovietIsraelSocialist RepublicsItalyUnited States of AmericaDrafts of Section 471 were discussed at the meetings held in Toronto in 1976 and in Sydney in 1979.As a result of thelatter meeting,a draft,Document 64(Central Office)89,was submitted to the National Committees for approval under the SixMonths Rule in April 1980.-5-The National Committees of the following countries voted explicitly in favour of publication:AustraliaNew ZealandAustriaPolandBelgiumRomaniaEgyptSpainFranceSwedenGermanySwitzerlandIsraelTurkeyItalyUnited States of AmericaJapanThe British National Committee returned a negative vote and gave the following reasons:The British National Committee voted against this standard because the unconditional application of the protectivemeasures in any electrical installation could cause danger.7ELECTRICAL INSTALLATIONS OF BUILDINGSPart 4:Protection for safetyChapter 47:Application of protective measures for safetySection 470:GeneralSection 471:Measures of protection against electric shock47.Application of protective measures for safety470.GENERAL470.1 Protective measures shall be applied in every installation,part of an installation,and toequipment,as required by the following sections of this chapter.470.2 The choice and application of protective measures according to conditions of externalinfluence shall be as specified in Chapter 48.470.3 Protection shall be ensured by:a)the equipment itself,orb)application of a protective measure as a process of erection,orc)a combination of a)and b).470.4 It shall be ensured that there is no mutual detrimental influence between different protectivemeasures applied in the same installation or part of an installation.471.MEASURES OF PROTECTION AGAINST ELECTRIC SHOCK471.1 Protection against electric shock in normal serviceAll electrical equipment shall be subject to one of the measures of protection against electricshock in normal service described in Sections 411 and 412.471.2 Protection against electric shock in case of a fault471.2.1 Except as provided in Sub-clause 471.2.2,all electrical equipment shall be subject to one ofthe measures of protection against electric shock in case of a fault described in Sections 411and 413,and to the conditions given in Sub-clauses 471.2.1.1 to 471.2.1.3.471.2.1.1 Protection by automatic disconnection of supply(Clause 413.1)shall be applied to anyinstallation except to parts of the installation to which another measure of protection isapplied.471.2.1.2 Where the application of the requirements of Clause 413.1 for protection by automaticdisconnection of supply is impracticable or undesirable,protection by the provision of a non-conducting location(Clause 413.3)or earth-free local equipotential bonding(Clause 413.4)maybe applied to certain parts of an installation.-9一471.2.1.3 Protection by safety extra-low voltage(Clause 411.1)by the use of Class II equipment orequivalent insulation(Clause 413.2)and by electrical separation(Clause 413.5)may be appliedin every installation,usually to certain equipment and certain parts of an installation.471.2.2 Protection against electric shock in case of a fault may be omitted for the followingequipment:-overhead line insulator wall brackets and metal parts connected to them(overhead linefittings)if they are not situated within arms reach;-steel reinforced concrete poles in which the steel reinforcement is not accessible;exposed conductive parts which,owing to their reduced dimensions(approximately50 mmx 50 mm)or their disposition,cannot be gripped or come into significant contactwith a part of the human body and provided that connection with a protective conductorcould only be made with difficulty or would be unreliable,Note.-This requirement applies,for example,to bolts,rivets,nameplates and cable clips.metal tubes or other metal enclosures protecting equipment in accordance with Clause 413.2.0