ASTM D257 Test Standard for DC Resistance or Conductivity of Insulating Materials

The ASTM D257 standard, published by the American Society for Testing and Materials (ASTM), covers direct current procedures for the measurement of dc insulation resistance, volume resistance, and surface resistance. From such measurements and from the geometric dimensions of samples and electrodes, conductivity and conductivities related to both volume and surface resistance of electrical insulating materials can be calculated.

These test methods are not suitable for use in measuring the electrical resistance/conductivity of moderately conductive materials. Use Test Method D4496 to evaluate such materials.

This standard describes several general alternative methodologies for measuring resistance (or conductivity). Specific materials can be optimally tested using standard ASTM test methods applicable to the specific material, which define both voltage stress limits and finite electrification times, as well as sample configuration and electrode geometry. These individual specific test methodologies will be able to better define precision and bias for determination.

This standard does not purport to address all, if any, safety concerns associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory restrictions prior to use.

Our organization also provides testing services within the scope of the ASTM D257 test standard for DC resistance or conductivity of insulation materials, within the framework of laboratory testing services.