This is the maximum voltage a material can withstand without conducting electricity through the thickness of the material.  Higher values indicate greater insulating efficiency.  Also, as the thickness of a component increases, so does its function as an insulator.

Volume Resistivity

This is a measurement of the resistance to the conduction of electricity provided by a unit cube of a material, at a given temperature and relative humidity.  It is also described as the ratio of thye voltage applied to one face of the specimen to the voltage exiting the opposite face of the cube.  Higher values indicate greater insulation effectiveness.

Surface Resistivity

This is the resistance of a material to the conduction of electricity across its surface.  As with volume resistivity, higher values indicate the material is less likely to allow a current to travel across its surface.

Dielectric Constant

This is theratio of capacitance of a capacitor in which the specimen acts as the dielectric, to the capacitance of a capacitor with dry air as the dielectric.  It is also termed permittivity.  Lower values indicate greater insulating ability of the material.

Dissipation

The dissipation or power factor, is the ratio of the power dissipated in an insulating material to the product of the effective voltage and current.

where t is the phase angle between applied voltage and current within the material being tested.

The dissipation factor indicates an insulating material's usefulness in minimising power loss caused by electrical heating.  Lower values equate with greater system efficiency.

Arc Resistance

This property is stated as the length of time a specimen resists the formation of a continuous, conducting path across its surface.  Higher values indicate increasing ability as an insulator.