1. This test method determines the electrical breakdown voltage of insulating liquid specimens. The breakdown test uses AC voltage in the power frequency range from 45 to 65 Hz.
  2. The dieelectric breakdown voltage is a measure of the ability of an insulating liquid to withstand electrical stress. The power-frequency breakdown voltage of a liquid is reduced by the presence of contaminants such as cellulosic fibers, conducting particles, dirt, and water. This test method is not recommended for evaluation of the breakdown voltage of liquids used in equipment that requires the application of vacuum and filtering of the oil before being placed into service. Test Method D-1816 should be used to determine the breakdown voltage of filtered and degassed oils.