Standard Test Method for
Comparative Tracking Index of Electrical Insulating
Materials1
This standard is issued under the fixed designation D 3638; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of the last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method evaluates in a short period of time the
low-voltage (up to 600 V) track resistance or comparative
tracking index (CTI) of materials in the presence of aqueous
contaminants.
1.2 The values stated in metric (SI) units are to be regarded
as standard. The inch-pound equivalents of the metric units
may be approximate.
1.3 This standard does not purport to address all of the
safety problems, if any, associated with its use. It is the
responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
D 618 Practice for Conditioning Plastics and Electrical
Insulating Materials for Testing2
D 647 Practice for Design of Molds for Test Specimens of
Plastic Molding Materials2
D 1711 Terminology Relating to Electrical Insulation3
D 1898 Practice for Sampling of Plastics2
2.2 IEC Publication:
112, Recommended Method for Determining the Comparative Track Index of Solid Insulating Materials Under
Moist Conditions, 1971 Second Edition4
3. Terminology
3.1 Definitions:
3.1.1 track—a partially conducting path of localized deterioration on the surface of insulating material.
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