With the development of electronic and electrical products towards miniaturization and high density, higher requirements have been put forward for the electrical trace resistance of insulation materials in harsh environments such as humidity and pollution. The Low Voltage Comparative Tracking Index Tester, as a key equipment for evaluating the electrical trace resistance of insulation materials, is widely used in fields such as electrical materials, household appliances, wires and cables, printed circuit boards, etc.

1、 Basic principles

Leakage tracing refers to the phenomenon of short circuit or breakdown caused by the formation of conductive channels on the surface of insulating materials due to partial discharge or electrolytic action under humid and polluted conditions. The Comparative Tracking Index (CTI) is an indicator of a material's ability to resist electrical traces.

The low voltage leakage tracing test simulates the environment in which pollutants and moisture interact in actual use by applying a specified voltage to the surface of the sample and dripping standard electrolyte. When the surface of the sample does not flashover or sustain combustion under the continuous action of 50 drops of electrolyte, it is considered that the material has the ability to resist electric traces at this voltage. By gradually adjusting the voltage, the CTI value of the material can be determined.

2、 According to the standard

GB/T 4207-2003 "Determination Method for Tracking Resistance Index and Comparative Tracking Index of Solid Insulation Materials"

ASTM D3638-1993 "Standard Test Method for Comparing Leakage Current Trace Index of Electrical Insulation Materials"

UL 746A "Introduction to Short term Performance Evaluation of Plastics"

IEC 60112A "Evaluation of Safety Performance of Electrical Equipment"

GB/T 2099.1-2008 "plugs and sockets for household and similar purposes - Part: General requirements"

GB/T 4706.1-2005 "Safety of household and similar electrical appliances - Part 1: General requirements"

IEC 60335 "Safety of household and similar electrical appliances"

IEC 884-1 "plugs and sockets for household and similar purposes - Part 1: General requirements"

3、 Typical application scenarios

1. Research and development of electrical insulation materials: evaluate the CTI level of new engineering plastics (such as PBT, PA, PC, etc.);

2. Material selection for household appliances such as rice cookers, microwave oven internal brackets, switch housings, and other components;

3. PCB substrate selection: High frequency and high-speed circuit boards require high CTI values to prevent signal interference and short circuits;

4. High voltage connector for new energy vehicles: Although it belongs to the high-voltage system, its low-voltage control circuit still needs to meet CTI requirements.