IEC_62305-4_212_CD_2.pdf

81/212/CDCOMMITTEE DRAFT(CD)IEC/TC or SC:TC 81Project numberIEC 62305-4,Ed.1Title of TC/SC:Lightning protectionDate of circulation2003-03-14Closing date for comments2003-06-20Also of interest to the following committeesSC 37A,TC 64,TC 77Supersedes documents81/191/NP 81/201/RVNFunctions concerned:Safety EMC Environment Quality assuranceSecretary:Mr.G.B.Lo Piparo(Italy)E-mail:lopiparorai.itTHIS DOCUMENT IS STILL UNDER STUDY AND SUBJECT TOCHANGE.IT SHOULD NOT BE USED FOR REFERENCE PURPOSES.RECIPIENTS OF THIS DOCUMENT ARE INVITED TO SUBMIT,WITHTHEIR COMMENTS,NOTIFICATION OF ANY RELEVANT PATENTRIGHTS OF WHICH THEY ARE AWARE AND TO PROVIDESUPPORTING DOCUMENTATION.Title:IEC 62305-4,Ed.1:Protection against lightning-Part 4:Electrical and electronic systems withinstructures(Titre):Introductory noteAs agreed at TC 81 meeting in Beijing(see document 81/206/RM),this document was elaborated byTC 81/WG 3 in close cooperation with TC 81 secretary.Coherence of this document with:IEC 62305-1;IEC 62305-2;IEC 62305-3;was finally checked and assured by TC 81 Secretariat.FORM CD(IEC)2002-08-08Copyright 2003 International Electrotechnical Commission,IEC.All rights reserved.It ispermitted to download this electronic file,to make a copy and to print out the content for the solepurpose of preparing National Committee positions.You may not copy or mirror the file orprinted version of the document,or any part of it,for any other purpose without permission inwriting from IEC.2 81/212/CDIEC 62305-4,Ed.1:Protection against lightning-Part 4:Electrical and electronic systems within structures 3 81/212/CDCONTENTSFOREWORD.6INTRODUCTION.71Scope.92Normative references.93Definitions.104Design and installation of LEMP protection measures.124.1Basic LPM system.124.2Lightning protection zones(LPZ).124.3Basic protection measures in an LPM system.135Earthing and bonding.145.1Earth termination system.145.2Bonding network.155.3Bonding bars.155.4Bonding at the boundary of LPZ.165.5Material and dimensions of bonding components.166Magnetic shielding and line routing.166.1Spatial shielding.176.2Shielding of internal lines.176.3Routing of internal lines.176.4Shielding of external lines.176.5Material and dimensions of magnetic shields.177Surge protective device system(SPD system).177.1Selection of SPD.187.1.1Selection with regard to protection level.187.1.2Selection with regard to location and to discharge current.187.2Erection of SPD system.207.2.1Location of SPD.207.2.2Connecting conductors.207.2.3Protective distance lpo due to oszillations.217.2.4Protective distance lpi due to induction phenomena.217.2.5Co-ordination of SPD.217.3Procedure for erection of an SPD system.228Management of an LPM system.228.1LPM system management plan.238.2Inspection of an LPM system.238.2.1Inspection procedure.238.2.2Documentation of the inspection.248.3Maintenance.24TABLES.25FIGURES.27Annex A(informative)Basics for evaluation of electromagnetic environment in a LPZ.40A.1 Harm to electrical and electronic systems from lightning.40A.1.1 Source of harm.40A.1.2 Victim of harm.40 4 81/212/CDA.1.3 Coupling mechanisms between victim and source of harm.40A.2 Spatial shielding,line routing and line shielding.41A.2.1 General.41A.2.2 Grid-like spatial shields.41A.2.3 Line routing and line shielding.42A.3 Magnetic field inside LPZs.42A.3.1 Approximation for the magnetic field inside LPZs.42A.3.1.1 Grid-like spatial shield of LPZ 1 in case of direct lightning strikes.42Examples.43A.3.1.2 Grid-like spatial shield of LPZ 1 in case of nearby lightning strikes.43Examples.45A.3.1.3 Grid-like spatial shields of LPZ 2 and higher.46A.3.2 Theoretical evaluation of the magnetic field due to direct lightning strikes.46A.3.3 Experimental evaluation of the magnetic field due to direct lightning strikes.47A.4 Calculation of induced voltages and currents.47A.4.1 Situation inside LPZ 1 in case of direct lightning strikes.47A.4.2 Situation inside LPZ 1 in case of nearby lightning strikes.48A.4.3 Situation inside LPZ 2 and higher.49Annex B(informative)Implementation of LEMP protection measures in existing structures.63B.1 Checklist.63B.2 Integration of new electronic systems into existing structures.63B.2.1 Overview of possible protection measures.63B.2.2 Establishment of LPZs for electrical and electronic systems.64B.3 Upgrading of power supply and cable installation inside the structure.65B.4 Protection by surge protective devices.65B.5 Protection by isolating interfaces.65B.6 Protection measures by line routing and shielding.66B.7 Upgrading of an existing LPS for spatial shielding of LPZ 1.66B.8 Protection by a bonding network.66B.9 Protection measures for externally mounted equipment.67B.9.1 Protection of the external equipment.67B.9.2 Reduction of overvoltages in cables.67B.10Upgrading of interconnections between structures.67B.10.1Isolating lines.67B.10.2Metallic lines.68Annex C(informative)SPD co-ordination.76C.1 General.76C.2 General objective of co-ordination.77C.2.1 Co-ordination principles.77