IEC_60157-1B-1979_scan.pdf

3-INTERNATIONAL ELECTROTECHNICAL COMMISSIONSecond supplement to Publication 157-1(1973)LOW-VOLTAGE SWITCHGEAR AND CONTROLGEARPart 1:Circuit-breakersFOREWORD1)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 thatsense3)In order to promote international unification,the IEC expresses the wish that all National Committees should adoptthe text 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 indicatedin the latter.PREFACEThis standard has been prepared by Sub-Committee 17B:Low-voltage Switchgear and Controlgear,of IEC TechnicalCommittee No.17:Switchgear and Controlgear.It combines two documents prepared by two different working groups.Elaboration of Part A:Amendments to be made to IEC Publications 157-1(2nd edition,1973)and 157-1A(1976)New Clauses 4.3.2.1,4.3.2.2 and 8.2.2 are the object of the first document for which a first draft was circulated inAugust 1975,according to the decision taken in Paris in April 1974.A second draft was circulated in December 1976 anddiscussed in Moscow in June 1977.The draft,Document 17B(Central Office)98,was submitted to the National Committeesfor approval under the Six MonthsRule in January 1978.The following countries voted explicitly in favour of publication:AustraliaJapanBelgiumNetherlandsBulgariaPolandCanadaSouth Africa(Republic of)ChinaSpainEgyptSwedenFinlandTurkeyFranceUnion of Soviet Socialist RepublicsGermanyUnited KingdomIsraelUnited States of AmericaOther Clauses of Part A are the object of the second document for which a first draft was circulated in July 1973,according to the decision taken in Stockholm in September 1972,and discussed in Paris in February 1974.A second draft was circulated in September 1974,according to the decision taken in Paris and discussed in The Hague inSeptember 1975.A third draft was circulated in December 1975,according to the decision taken in The Hague in December 1975.A fourth draft was circulated in October 1976 and discussed in Moscow in June 1977.The draft,Document 17B(CentralOffice)99,was submitted to the National Committees for approval under the Six MonthsRule in January 1978.-5The following countries voted explicitly in favour of publication:AustraliaNetherlandsBelgiumPolandBulgariaSouth Africa(Republic of)CanadaSpainEgyptSwedenFinlandTurkeyFranceUnion of Soviet Socialist RepublicsGermanyUnited KingdomHungaryUnited States of AmericaJapanElaboration of Part B:Appendix D:Co-ordination of circuit-breakers with separate fuses associated in the same circuitPart B comprises Appendix D to Publication 157-1,as included in Publication 157-1A(1976)and amended in compliancewith the above Document 17B(Central Office)99.Other IEC publications quoted in this standard:Publications 157-1A:First supplement to Publication 157-1(1973):Low-voltage Switchgear and Controlgear,Part 1:Circuit-breakers.157-2:(Under consideration).269-1:Low-voltage Fuses.Part 1:General requirements.269-2:Part 2:Supplementary Requirements for Fuses for Industrial Applications.269-3:Part 3:Supplementary Requirements for Fuses for Domestic and Similar Applications.439:Factory-built Assemblies of Low-voltage Switchgear and Controlgear.