ASTM_E_2908_-_12.pdf

Designation:E290812Standard Guide forFire Prevention for Photovoltaic Panels,Modules,andSystems1This standard is issued under the fixed designation E2908;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This guide describes basic principles of photovoltaicmodule design,panel assembly,and system installation toreduce the risk of fire originating from the photovoltaic sourcecircuit.1.2 This guide is not intended to cover all scenarios whichcould lead to fire.It is intended to provide an assembly ofgenerally-accepted practices.1.3 This guide is intended for systems which contain pho-tovoltaic modules and panels as dc source circuits,although therecommended practices may also apply to systems utilizing acmodules.1.4 This guide does not cover fire suppression in the eventof a fire involving a photovoltaic module or system.1.5 This guide does not cover fire emanating from othersources.1.6 This guide does not cover mechanical,structural,electrical,or other considerations key to photovoltaic moduleand system design and installation.1.7 This guide does not cover disposal of modules damagedby a fire,or other material hazards related to such modules.1.8 UnitsThe values stated in SI units are to be regardedas standard.No other units of measurement are included in thisstandard.1.9 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E772 Terminology of Solar Energy ConversionE2481 Test Method for Hot Spot Protection Testing ofPhotovoltaic Modules2.2 Other Standards and Documents:IEC 61215 Crystalline silicon terrestrial photovoltaic(PV)modulesDesign qualification and type approvalIEC 61730 Photovoltaic(PV)module safety qualificationNorth American Board of Certified Energy Practitioners(NABCEP),Study Guide for Photovoltaic System Install-ersNFPA 70 US National Electrical Code(article 690)UL 1703 Standard for Flat-Plate Photovoltaic Modules andPanelsUL 1741 Inverters,Converters,and Controllers for Use inIndependent Power Systems3.Terminology3.1 Definitions of terms used in this standard may be foundin Terminology E772.3.2 Definitions:3.2.1 ground fault,na condition where there is an unin-tended electrical connection between the active PV circuit andground.4.Summary of Practice4.1 Photovoltaic modules and panels should be designed tominimize the risk of fire and should be assembled with goodquality-control practices.1This test method is under the jurisdiction of ASTM Committee E44 on Solar,Geothermal and OtherAlternative Energy Sources and is the direct responsibility ofSubcommittee E44.09 on Photovoltaic Electric Power Conversion.Current edition approved Dec.1,2012.Published December 2012.DOI:10.1520/E2908-12.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.2 Photovoltaic systems should be designed to minimizethe risk of fire,and installed with fire safety in mind.Installersshould be aware of PV-related fires that have occurred and thecause of those fires.5.Significance and Use5.1 Photovoltaic modules are electrical dc sources.dcsources have unique considerations with regards to arc forma-tion and interruption,as once formed,the arc is not automati-cally interrupted by an alternating current.Solar modules areenergized whenever modules in the string are illuminated bysunlight,or during fault conditions.5.2 With the rapid increase in the number of photovoltaicsystem installations,this guide attempts to increase awarenessof methods to reduce the risk of fire from photovoltaic systems.5.3 This guide is intended for use by module manufacturers,panel assemblers,system designers,installers,and specifiers.5.4 This guide may be used to specify minimum require-ments.It is not intended to capture all conditions or scenarioswhich could result in a fire.6.Arcing6.1 dc Arcing:6.1.1 An electrical arc can form where an electric potentialexists between two neighboring conductors.Unlike ac arcswhich may be extinguished during the alternating-cycle ofcurrent,a dc arc will be maintained indefinitely until inter-rupted.A dc arc will be sustained until the voltage potential isreduced,an arc-detection device disrupts the flow of current,orthe effective distance between the conductors becomes toolarge to sustain the arc.Even once the arc is e