The insulation resistance of the connector refers to the resistance value that a DC voltage is applied to the insulation part of the connector, so that leakage current is generated on the surface or inside of the insulation part. If the insulation resistance value is low, it may form a feedback circuit, increase power loss, cause interference, etc. Excessive leakage current can cause heat or direct current electrolysis to destroy the insulation, cause a short circuit, and endanger safety.

The main factors that affect the insulation resistance of the connector are: connector temperature, connector humidity, connector pollution, connector oxidation, and the properties of the material itself. For example, the volume resistivity of the insulating material determines the insulation resistance.