Designation: D149 - 09 (Reapproved 2013) An American National Standaro INTERNATIONAL Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at Commercial Power Frequencies1 This standard is issued under the fixed designation D149; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval. This standard has been approved for use by agencies of the Department of Defense. 1. Scope* dielectric breakdown voltage along the interface between a solid specimen and a gaseous or liquid surrounding medium 1.1 This testmethod covers proceduresforthe determina- (flashover). With the addition of instructions modifying Sec- tion of dielectric strength of solid insulating materials at commercial power frequencies, under specified conditions.2 tion 12, this test method is also suitable for use for proof testing. 1.2 Unless otherwise specified, the tests shall be made at 60 Hz. However, this test method is suitable for use at any 1.8 This test method is similar to IEC Publication 243-1. All frequency from 25 to 800 Hz. At frequencies above 800 Hz, procedures in this method are included in IEC 243-1.Differ- dielectric heating is a potential problem. ences between this method and IEC 243-1 are largely editorial. 1.3 This test method is intended to be used in conjunction 1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the withanyASTM standard orotherdocumentthatreferstothis responsibility of the user of this standard to establish appro- test method. References to this document need to specify the priate safety and health practices and determine the applica- particular options to be used (see 5.5). bility of regulatory limitations prior to use. Specific hazard 1.4 It is suitable for use at various temperatures, and in any statements are given in Section 7. Also see 6.4.1. suitable gaseous or liquid surrounding medium. 2. Referenced Documents 1.5 This test method is not intended for measuring the dielectric strength of materials that are fluid under the condi- 2.1 ASTM Standards:4 tions of test. D374 Test Methods for Thickness of Solid Electrical Insu- lation (Withdrawn 2013)5 1.6 This test method is not intended for use in determining D618 Practice for Conditioning Plastics for Testing intrinsic dielectric strength, direct-voltage dielectric strength, D877 Test Method for Dielectric Breakdown Voltage of or thermal failure under electrical stress (see Test Method Insulating Liquids Using Disk Electrodes D3151). D1711 Terminology Relating to Electrical Insulation 1.7This testmethod is most commonlyused todetermine D2413 Practice for Preparation of Insulating Paper and the dielectric breakdown voltage through the thickness of a test Board Impregnated with a Liquid Dielectric specimen (puncture). It is also suitable for use to determine D3151 Test Method for Thermal Failure of Solid Electrical Insulating Materials Under Electric Stress (Withdrawn 2007)5 I This test method is under the jurisdiction of ASTM Committee D09 on D3487 Specification for Mineral Insulating Oil Used in Electrical and Electronic Insulating Materials and is the direct responsibility of Subcommittee D09.12 on Electrical Tests Electrical Apparatus Current edition approved April 1, 2013. Published April 2013. Originally D5423 Specification for Forced-Convection Laboratory Ov- approved in 1922. Last previous edition approved in 2009 as D149-09. DOI: ens for Evaluation of Electrical Insulation 10.1520/D0149-09R13. Bartnikas, R., Chapter 3,"High Voltage Measurements," Electrical Properties of Solid Insulating Materials, Measurement Techniques , Vol. IIB, Engineering 4For referenced ASTM standards, visit the ASTM website,