IEC_81_230_INF.pdf

81/230/INFFor IEC use only2003-07-25INTERNATIONAL ELECTROTECHNICAL COMMISSIONTECHNICAL COMMITTEE No.81:LIGHTNING PROTECTIONLiaison with other TC/SC and with others organisationsOverlapping TC 64/TC 81(to be discussed under draft agenda item 12.2 at the forthcoming TC 81 meeting to be held in Palma deMallorca 29th and 30th September 2003)At the co-ordination meeting of the Technical committees SC 28A,SC 37A,TC 42,TC 64,SC 77B and TC81,which took place in Paris,30 November 1993,the following responsibilities have been defined.TC 64 Definition of the stresses(voltage/current surges)coming from the LV supply system,on SPDs beingpart of the electrical LV supply Requirements for selection and erection of SPDs based on the information given by SC 37A.Co-ordination of safety aspects and requirements of the relevant standards for selection and erection ofprotective devices,where both lightning protection(TC 81)and other electrical installations(TC 64)are in thesame establishment and to which have to be taken into consideration.TC 81 Protection of persons,installation and apparatus in buildings against hazardous effects of direct andnearby lightning strokes on the building.Specification of stresses on connecting means and SPDs connected between electrical systems in thebuilding and the LPS earthing arrangement where an LPS in provided.These decisions have been published by the Central Office of the IEC:Document 64(Secretariat)670A/February 1994.Taking this into account,the following table was elaborated.Conclusions:There are several overlapping items in the existing papers,which should be checked according to thedefinitions of responsibilities TC 64/TC 81(as mentioned above).TC 81/WG 5 has started their work on IEC 62305-5.Also here overlapping is possible,if not only theprotection of services outside the structure to be protected,but also internal measures(like selection andinstallation SPDs)would be taken into account.To clarify overlapping items(as listed in the table)a meeting of experts TC 64 and TC 81 is necessary.There is a sleeping JWG 64/81,which should be able to handle these items.2 81/230/INFSTANDARDS OF TC 64STANDARDS OF TC 81REMARKSscopeIEC 60364-4-44 Amd.1 Paragraph443 Protection againstovervoltages of atmospheric.this clause deals with protection ofelectrical installations againsttransient overvoltages of atmosphericorigin transmitted by the supplydistribution system and againstswitching overvoltages.Note 2:For protection againsttransient overvoltages due to directlightning,see the IEC 61024 seriesand the IEC 61312 seriesIEC 62305-4,Paragraph 1 Scope.information for the design,installation,inspectionmaintenance and testing of aprotection system against thelightning electromagneticimpulse.to reduce failures of electricaland electronic systems.scope-protectionof humanbeingsEC 60364-4-44“Foreword”.IEC 60364-4-44 has beenprepared by IEC technical committee64:Electrical installations andprotection against electric shock.“IEC 62305-3,Paragraph 1Scope.This part of IEC 62305provides the requirements.andfor protection against injuries ofliving being due to touch and stepvoltages in vicinity of LPS.“protectionofequipment-isolationco-ordinationIEC 60364-4-44 Amd.1 Paragraph440“Introduction”.Clause 443 is intended to describethe means by which transientvoltages can be limited to reduce therisk of an acceptable level of failure inthe installation and in the electricalequipment connected to it.Thisapproach is in line with the principlesof insulation co-ordination containedin IEC 60664-1.”IEC 60364-4-44 Amd.1 Paragraph443.4“Required impulse withstandvoltage of equipment”.equipment shall be selected sothat its rated impulse withstandvoltage is not less than the requiredimpulse withstand voltage asspecified in Table 44B.”IEC 62305-4,Paragraph 7.1.1Selection(of SPD)with regardof protection level Rated impulse voltagewithstand level Ui of equipment tobe protected(installation orapparatus)should be declared bythe manufacturer.“;“Equipment is protected,if itsrated impulse withstand voltageUi is greater or equal to theeffective protection level Uprot.”3 81/230/INFerection ofSPDsIEC 60364-5-53 Paragraph 534.1“General”.This clause gives therequirements for the selection anderection of SPDs .to obtain a limitation oftransient overvoltages ofatmospheric origin transmitted viathe supply distribution system andagainst switching overvoltages;SPDs for the protection againsttransient overvoltages caused bydirect lightning strokes.”IEC 62305-4,Paragraph 7.2Erection of SPD system”The efficiency of an SPDsystem depends not only onproper selection of SPD butmainly on proper erection.Mainaspects to be considered inerection of an SPD system are:location of SPD;connecting conductors;protective distance.”selection ofSPDsIEC 60364-5-53 Paragraph 534.2.1“Use of SPD”“IEC 60364-4-44,claus3 443,includes protection againstovervoltages of atmospheric origin(caused by indirect,distant lightningstrokes)and switching overvoltages.This protection is