C.D.U./U.D.C.: 621.3.061.001.13 744.423 COMMISSIONELECTROTECHNIQUEINTERNATIONALE (affilie a I'Organisatjon Internationale de Normalisation -ISO) NORME DE LA CEI INTERNATIONALELECTROTECHNICALCOMMISSION (affiliated to the international Organization for Standardization - ISO) IECSTANDARD Publication 113-4 Premiere édition-First edition 1975 Schemas, diagrammes, tableaux Quatrieme partie: Recommandations pour 'etablissement des schemas des circuits Diagrams, charts, tables Part 4: Recommendations for the preparation of circuit diagrams FUR REFERENCE ONLI STANDARDS AND SAFETY SFCTION NATIONAEFNERGY AITHORITY Droits de reproduction reserves - Copyright-all rights reserved No part of this publiation may be reproduced or utlized in any quelqueformequecesoitetparaucunprocede,electronique oumca form or by any means, efectronic or mechanical, including photocopying nique, y compris la photocopie et les microfilms, sans F'accord ecrit de I'editeur. and microfim, without permission in writing from the publisher. Bureau Central de la Commission Electrotechnique Internationale 1, rue de Varembe Geneve, Suisse IEC Prix Fr. s. VoL.1o 70.50 Price S. Fr. CONTENTS Pages FOREWORD 5 PREFACE 5 Clause 1.Scope 7 2. Purpose of a circuit diagram 7 3. Contents of a circuit diagram 7 4. General guiding principles 7 4.1 Layout 7 4.2 Functional grouping 9 5.Arrangement of symbols on diagrams 9 9 5.1 Methods for indicating symbol location 5.2 Methods of circuit representation 11 5.3 Separation of symbols in detached representation 11 5.4 Methods of referencing parts in the case of detached representation 15 5.5Representation ofunused elements 15 5.6 Representation of contacts 17 6. Representation of circuits 21 21 6.1General 6.2 Representation of supply 21 6.3 Representation of main circuits 21 6.4 Detailed recommendations 23 31 6.5Simplifications 6.6 Recommended layout for some fundamental circuits 39 7. Markings and designations 43 45 7.1 Item designation 7.2 Designation of terminals and junctions 45 8. Explanatory notes 45 45 9. Inscription of technical data 45 10. Examples of complete circuit diagrams FIGURES 37to 48.1 50 INTERNATIONAL ELECTROTECHNICAL COMMISSION DIAGRAMS, CHARTS, TABLES Part 4: Recommendations for the preparation of circuit diagrams FOREWORD 1) The formal decisioris or agreements of the IEC on technical matters, prepared by Technical Committees on which all the National Committees having a special interest therein are represented, express, as nearly as possible, an international consensus 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 that sense. 3) In order to promote international unification, the IEC expresses the wish that all National Committees should adopt the text of the IECrecommendationfortheirnational rules in sofaras national conditionswill permit.Anydivergencebetween theIECrecom- mendation and the corresponding national rules should, as far aspossible, be clearly indicated in thelatter. PREFACE This recommendation has been prepared by Sub-Committee SC 3B, Preparation of Diagrams, Charts and Tables. Item Designation, of-IEC Technical Committee No. 3, Graphical Symbols. A first draft, prepared by the Secretariat of SC 3B, was discussed at the meeting held in Helsinki in 1971, and a second draft was discussed at the meeting held in Paris in 1972.The draft was submitted to the National Committees for approval under the Six Months' Rule in April 1973. Thefollowing countries voted explicitly in favour of publication of Part 4: Australia Netherlands Austria Portugal Belgium Romania SouthAfrica (Republic of) Denmark Finland Sweden France Switzerland Germany Turkey Italy United Kingdom Japan United StatesofAmerica