ASTM D8687-26
Standard Test Method for Determination of the Electric Tangential Interfacial Surface Discharge of Solid Dielectric Materials in a Liquid
| Standard number: | ASTM D8687-26 |
| Released: | 01.09.2026 |
| Status: | Active |
| Pages: | 8 |
| Section: | 10.02 |
| Keywords: | breakdown; breakdown voltage; creep strength; creep voltage; dielectric breakdown voltage; dielectric strength; negative lightning impulse; power frequency; tangential interfacial surface discharge; |
| ASTM number: | ASTM D8687 |
1.1 This test method covers the determination of the tangential interfacial surface breakdown voltage, also known as interfacial surface creep breakdown, of solid insulation materials in an insulating liquid. The test procedures will include:
1.1.1 AC line frequency.
1.1.2 Full-wave impulse defined as 1.2 μs by 50 μs.
1.2 The testing will determine the influence of combining solid and liquid dielectric insulation materials on the tangential interfacial surface breakdown. The solid insulation can either be impregnated or conditioned with the liquid insulation. The test procedure should include a sufficient number of determinations to provide a mean breakdown using a 50 % Gaussian distribution or a 1 % or 2 % probability of breakdown using either a two- or three-parameter Weibull distribution.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.