What is a tracking test?

A tracking test, also known as a leakage current or current tracking test, is a type of electrical test used to evaluate the resistance of insulating materials to track formation. It is performed to assess the ability of a material to resist the formation of conductive paths (tracks) caused by the presence of moisture, contaminants, or other factors.

Tracks can occur on the surface of an insulating material when there is a breakdown in its electrical properties due to the presence of conductive substances. This breakdown can happen under the influence of moisture, pollution, and/or electrical stress, leading to the formation of a conductive path across the material's surface. These paths can cause electrical leakage, short circuits, and potential failure of the electrical device or system.

The tracking test is particularly important for materials or products used in electrical and electronic applications, such as insulating cables, connectors, circuit boards, and power distribution systems. The test simulates the real-world conditions that these materials might be exposed to, such as high humidity, dust, or the presence of corrosive substances.

During the tracking test, a voltage is applied to the material under test while electrically conductive liquid or solid contaminants (typically a saline solution) are applied to its surface. The test measures the ability of the material to withstand the electrical stress without the formation of tracks. The tracking test result is usually reported as the time until the first occurrence of tracking (in minutes) or as the number of tracking events.

The test method and acceptance criteria for tracking tests are often specified by industry standards, such as the International Electrotechnical Commission (IEC), American Society for Testing and Materials (ASTM), or other relevant regulatory bodies. These standards provide guidelines on test conditions, test equipment, sample preparation, and evaluation criteria to ensure consistent and reliable results.

By conducting tracking tests, manufacturers and designers can assess the suitability of insulating materials for specific applications, identify potential weaknesses, and make informed decisions for product improvement and safety enhancement.