The document describes four common tests used to evaluate the insulation properties of materials: 1. Insulation Resistance (IR) Test - Measures the quantifiable resistance value of a product's insulation. 2. Dielectric Breakdown Strength Test - Applies increasing test voltage until the dielectric fails or breakdown occurs allowing too much current to flow. 3. Dielectric Withstand Voltage Test (DWS) - Applies a standard test voltage below the breakdown voltage and monitors resulting leakage current. 4. Conductive Anodic Filament Test (CAF) - Determines a material's capability for withstanding various design feature spacings under high humidity and voltage conditions.