>> P.109
StandardnameStandardNumberAbstractProtectionagainstlightning–Part3:PhysicaldamagetostructuresandlifehazardIEC62305–3Protectionagainstlightning–Part4:ElectricalandelectronicsystemswithinstructuresIEC62305-3providestherequirementsforprotectionofastructureagainstphysicaldamagebymeansofalightningprotectionsystem(LPS),andforprotectionagainstinjurytolivingbeingsduetotouchandstepvoltagesinthevicinityofanLPS(seeIEC62305-1).Thissecondeditioncancelsandreplacesthefirstedition,publishedin2006,andconstitutesatechnicalrevision.Thiseditionincludesthefollowingsignicanttechnicalchangeswithrespecttothepreviousedition:1)MinimumthicknessesofmetalsheetsormetalpipesgiveninTable3forair-terminationsystemsareassumedasnotabletopreventhot-spotproblems.2)Steelwithelectro-depositedcopperisintroducedasmaterialsuitableforLPS.3)Somecross-sectionalareasofLPSconductorswereslightlymodied.4)Forbondingpurposes,isolatingsparkgapsareusedformetalinstallationsandSPDforinternalsystems.5)Twomethodssimpliedanddetailedareprovidedforevaluationofsepara-tiondistance.6)Protectionmeasuresagainstinjuriesoflivingbeingsduetoelectricshockareconsideredalsoinsidethestructure.7)ImprovedinformationforLPSinthecaseofstructureswithariskofexplosionaregiveninAnnexD(normative).IEC62305-4providesinformationforthedesign,installation,inspection,maintenanceandtestingofelectricalandelectronicsystemprotection(SPM)toreducetheriskofpermanentfailuresduetolightningelectromagneticimpulse(LEMP)withinastructure.Thissecondeditioncancelsandreplacesthefirstedition,publishedin2006,andconstitutesatechnicalrevision.Thiseditionincludesthefollowingsignicanttechnicalchangeswithrespecttothepreviousedition:1)Isolatinginterfacescapableofreducingconductedsurgesonlinesenteringthestructureareintroduced.IEC62305-42)Minimumcross-sectionsforbondingcomponentsareslightlymodied.3)Firstnegativeimpulsecurrentisintroducedforcalculationpurposesaselectromagneticsourceofharmtotheinternalsystems.4)SelectionofSPDwithregardtovoltageprotectionlevelisimprovedtotakeintoaccountoscillationandinductionphenomenainthecircuitdownstreamofSPD.5)AnnexCdealingwithSPDcoordinationiswithdrawnandreferredbacktoSC37A.6)AnewinformativeAnnexDisintroducedgivinginformationonfactorstobeconsideredintheselectionofSPDs.109
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