Conditioning for insulation resistance measurements

This paper is concerned with the aspects of conditioning pertinent to electrical resistance measurements as covered by the scope of Standard Methods of Test for Electrical Resistance of Insulating Materials (ASTM Designation: D-257). Attention is therefore directed to d-c testing of electrical insulation. Further, the primary interest will be in general engineering practice with solid insulations and, to a lesser extent, with liquids; gasses will be excluded. Such theory as contributes to an understanding of testing practices will be discussed. It is to be hoped that a discussion of electrical conduction has aided an understanding of the effects of conditioning on the resistance of insulators; that a discussion of resistance measurements has provided an awareness of the errors that may be introduced when tests are made on conditioned specimens, and that means for avoiding the errors are understood; finally, that requirements for suitable conditioning chambers and procedures in their use are adequately described.