ASTM D3638-12, “Standard Test Method for Comparative Tracking Index of Electrical Insulating Materials,” is now available from Document Center Inc. This test method evaluates relatively quickly the low-voltage (up to 600 V) track resistance or comparative tracking index (CTI) of materials in the presence of aqueous contaminants.
Electrical equipment can fail as a result of electrical tracking of insulating material that is exposed to various contaminating environments and surface conditions. There are a number of ASTM and other tests designed to quantify behavior of materials, especially at relatively high voltages.
ASTM D3638 is an accelerated test which uses relatively low test voltages. It provides a comparison of the performance of insulating materials under wet and contaminated conditions. The comparative tracking index is not related directly to the suitable operating voltage in service.
While tracking tests serve to differentiate materials under given conditions, the results should not be used to infer either direct or comparative service behavior of an application design. Instead these test results provide a tool for judging the suitability of materials for a given application. This suitability then needs to be verified through testing the design in actual end use or under conditions which simulate end use as closely as possible.
All current ASTM standards and many of the obsolete revisions are available from Document Center Inc. in both paper and pdf format. Use our website, www.document-center.com, to order. Or contact us by phone (650-591-7600), fax (650-591-7617) or email (info@document-center.com). We’ve been selling standards and helping folks with their standards questions and requirements for 30 years now, so we have the expertise to help you too!