IEC_60364-4-444-1996_scan.pdf

12NORMECEIINTERNATIONALEIECINTERNATIONAL364-4-444STANDARDPremiere editionFirst edition1996-04Installations lectriques des batiments-Partie 4:Protection pour assurer la securite-Chapitre 44:Protection contre les surtensions-Section 444:Protection contre les interferenceslectromagntiques(IEM)dans les installations des batimentsElectrical installations of buildings-Part 4:Protection for safety-Chapter 44:Protection against overvoltages-Section 444:Protection againstelectromagnetic interferences(EMI)in installations of buildings CEI 1996 Droits de reproduction rservs-Copyright-all rights reservedAucune partie de cette publication ne peut tre reproduite ni No part of this publication may be reproduced or utilized inutilis6e sous quelque forme que ce soit et par aucun pro-any form or by any means,electronic or mechanical,cd6,lectronique ou mcanique,y compris la photocopie et including photocopying and microfilm,without permissionles microfilms,sans accord 6crit de 6diteur.in writing from the publisher.Bureau Central de la Commission Electrotechnique Intemationale 3,rue de Varemb Genve,SuisseCommission Electrotechnique InternationaleCODE PRIXIECInternational Electrotechnical CommissionPRICE CODELMemAyHapoAHaR 3neKTpoTexHecKa HoMHcCHRPour prix,voir catalogue en vigueurFor price,see current catalogueIECVO L 12.364-4-4441EC:1996-3-INTERNATIONAL ELECTROTECHNICAL COMMISSIONELECTRICAL INSTALLATIONS OF BUILDINGSPart 4:Protection for safetyChapter 44:Protection against overvoltagesSection 444:Protection against electromagnetic interferences(EMI)in installations of buildingsFOREWORD1)The IEC(International Electrotechnical Commission)is a worldwide organization for standardizationcomprising all national electrotechnical committees(IEC National Committees).The object of the IEC is topromote international co-operation on all questions concerning standardization in the electrical and electronicfields.To this end and in addition to other activities,the IEC publishes International Standards.Theirpreparation is entrusted to technical committees;any IEC National Committee interested in the subject dealtwith may participate in this preparatory work.International,governmental and non-governmental organizationsliaising with the IEC also participate in this preparation.The IEC collaborates closely with the internationalOrganization for Standardization(ISO)in accordance with conditions determined by agreement between the.two organizations.2)The formal decisions or agreements of the IEC on technical matters,express as nearly as possible,aninternational consensus of opinion on the relevant subjects since each technical committee has representationfrom all interested National Committees.3)The documents produced have the form of recommendations for international use and are published in theform of standards,technical reports or guides and they are accepted by the National Committees in thatsense.4)In order to promote international unification,IEC National Committees undertake to apply IEC InternationalStandards transparently to the maximum extent possible in their national and regional standards.Anydivergence between the IEC Standard and the corresponding national or regional standard shall be clearlyindicated in the latter.5)The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for anyequipment declared to be in conformity with one of its standards.gAttention is drawn to the possibility that some of the elements of this International Standard may be thesubject of patent rights.IEC shall not be held responsible for identifying any or all such patent rights.International standard IEC 364-4-444 has been prepared by IEC technical committee 64:Electrical installations of buildings.The text of this standard is based on the following documents:FDISReport on voting64/792/FD1S64/866/RVDFull information on the voting for the approval of this standard can be found in the report onvoting indicated in the above table.Annex A is for information only.364-4-444 IEC:1996-5-INTRODUCTIONElectromagnetic interferences(EMI)can disturb or damage information technology systems orequipment,equipment with electronic components or circuits.Currents due to lightning,switching operations,short circuits and other electromagneticphenomena can cause overvoltages and electromagnetic interference.These effects appear:-where large metal loops exist1);and-where different electrical wiring systems are installed on different routes,e.g.for powersupply and for signalling information technology equipment within a building.The value of the induced voltage depends on the rate of rise(di/df)of the interference current,and on the size of the loop.Power cables carrying large currents with a high rate of rise of current(di/dt)(e.g.the startingcurrent of lifts or currents controlled by rectifiers)can induce overvoltages in cables ofinformation technology systems,which can influence or damage information technology orsimilar electrical equipment.In or near rooms for medical use,electric or magnetic fields of electrical installations caninterfere with medical electrical equipment.1)Equipotential bonding systams,stncural metalwork or pipe systems for non-electrical supplies,e.g.for water,gas,heating or air conditioning can creae such induction loops.364-4-444IEC:1996-7-ELECTRICAL INSTALLATIONS OF BUILDINGS-Part 4:Protection for safety-Chapter 44:Protection against overvoltages-Section 444:Protection against electromagnetic interferences(EMI)in installations of buildings444.1 ScopeThis section of IEC 364-4 provides information for architects of buildings and for designersand installers of electrical installations of buildings on some installation concepts which canlimit electromagnetic interference(EMI).Basic considerations are given here to mitigate thesedisturbances.Further requirements are given in other chapters or sections of IEC 364,e.g.IEC 364-5-548 or in other IEC Standards,e.g.IEC 1000-2,future IEC 1000-5,IEC 1024-1 andIEC 1312-1.These considerations are in line with the above-mentioned standards(seefigure 5).444.2 Normative referencesThe following normative documents contain provisions which,through reference in this text,constitute provisions of this section of IEC 364-4.At the time of publication,the editionsindicated were valid.All normative documents are subject to revision,and parties toagreements based on this section of IEC 364-4 are encouraged to investigate the possibility ofapplying the most recent editions of the normative documents indicated below.Members of IECand ISO maintain registers of currently valid International Standards.IEC 364-4-41:1992,Electrical installations of buildings-Part 4:Protection for safety-Chapter 41:Protection against electric shockIEC 364-5-54:1980,Electrical installations of buildings-Part 5:Selection and erection ofelectrical equipment-Chapter 54:Earthing arrangements and protective conductorsIEC 742:1983,Isolating transformers and safety isolating transformers-RequirementsIEC 1000-2-5:1995,Electromagnetic compatibility(EMC)-Part 2:Environment-Section 5:Classification of electromagnetic environmentsIEC 1024-1:1990,Protection of structures against lightning-Part 1:General principlesIEC 1312-1:1995,Protection against lightning electromagnetic impulse-Part 1:Generalprinciples364-4-444 IEC:1996-9-IEC 364-5-548:1996,Electrical installations of buildings-Part 5:Selection and erection of elec-trical equipment-Chapter 54:Earthing arrangements and protective conductors-Section 548:Earthing arrangements and equipotential bonding for information technology equipment444.3MeasuresMeasures to be taken against electric and magnetic influences on electrical equipment:All:electrical equipment shall meet the appropriate electromagnetic compatibility(EMC)requirements,and shall be in accordance with the relevant EMC standards.Reference is also made to IEC 364-3:321.10,Electromagnetic,electrostatic or ionizinginfluence;and Amendment 1 to IEC 364-5-51;515.3,Electromagnetic compatibility(EMC);515.3.1,Choice of the immunity and emission levels.Furthermore,reference is made to IEC 364-5-548.Consideration shall be given by the planner and designer of the electrical installations to thefollowing(see also figure 4)for reducing the effect of induced overvoltages and EMI:444.3.1 Location of potential sources of interference relative to sensitive equipment.444.3.2 Location of sensitive equipment relative to high electrical current such as in busbarsor in equipment,e.g.lifts.444.3.3.Provision of filters and/or surge protective devices in the circuits feeding sensitiveelectrical equipment.444.3.4.Selection of protective devices with appropriate time delay characteristics to avoidunwanted tripping on transients.444.3.5 Bonding of metal enclosures and screening.444.3.6 Adequate separation(distance or screening)of power and signal cables,and cross-overs at right angles.444.3.7 Adequate separation(distance or screening)of power and signal cables from downconductors of LPS(see IEC 1024-1 and figure 5).444.3.8 Avoidance of inductive loops by selection of a common route for the wiring ofdifferent systems(see also 444.4.4).444.3.9 Use of screened and/or twisted pair signal cables.444.3.10 Bonding connections to be made as short as possible.444.3.11 Wiring systems with single-core conductors to be enclosed in bonded metallicenclosures or equivalent.