IEC 62631-3-1:2016 covers a method of test for the determination of volume resistance and volume resistivity of electrical insulation materials by applying a DC voltage. This edition includes the following significant technical changes with respect to the second edition of IEC 60093: a) IEC 60093 has been completely revised, both editorially and technically, and incorporated into the new IEC 62631 series; b) test methods have been updated to current day state of the art; c) volume and surface resistance and resistivity are now separated to appear in this part of IEC 62631 and in IEC 62631-3-2, respectively.