Designation:D668−12StandardTestMethodsofMeasuringDimensionsofRigidRodsandTubesUsedforElectricalInsulation1ThisstandardisissuedunderthefixeddesignationD668;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thesetestmethodscoverthemeasurementofthedimensionsofallrigidrodsandtubesusedaselectricalinsulation,thelimitationsimposedbeingthoseofthesizerangeofthemorecommonformsofmeasuringinstrumentsused.1.2Wherethenumberofteststobemadeorthespecifica-tionscoveringtherodortubejustifyitsuse,itisacceptabletouseanaccuratelycalibrated“go-and-no-go”ringgageofsuitablesize.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2D374TestMethodsforThicknessofSolidElectricalInsu-lation(Withdrawn2013)3D1711TerminologyRelatingtoElectricalInsulation3.Terminology3.1Definitions—FordefinitionsoftermsusedinthesetestmethodsrefertoTerminologyD1711.4.SignificanceandUse4.1Thesetestmethodsareusedtomeasurethedimensionsoftherodortubetodetermineconformancewithspecificationsonfulllengthsorcutlengths.Themeasurementscanalsobeusedformanufacturingcontrol,determinationofuniformity,dimensionalstability,andphysicalandelectricalpropertiesoftherodsandtubes.5.Conditioning5.1Conditionspecimenspriortotestingforatleast48hat2361°Cand5062%relativehumidity.Performtestsinaircontrolledatthattemperatureandhumidity.6.MethodofMeasurement6.1Makealldiameterandwallthicknessmeasurementsforspecimenswithdimensions300mm(12in.)andunderinaccordancewiththeproceduredescribedinTestMethodsD374asapplicable.Closethemicrometerorverniercaliperslowlyonthespecimenuntilcontactismadewithoutappre-ciabled...
