Liquid dielectrics, because of their inherent properties, appear as though they would
be more useful as insulating materials than either solids or gases. This is because both
liquids and solids are usually 103 times denser than gases and hence, from Paschen's
law it should follow that they possess much higher dielectric strength of the order of
107 V/cm. Also, liquids, like gases, fill the complete volume to be insulated and
simultaneously will dissipate heat by convection. Oil is about 10 times more efficient
than air or nitrogen in its heat transfer capability when used in transformers. Although
liquids are expected to give very high dielectric strength of the order of 10 MV/cm,
in actual practice the strengths obtained are only of the order of 100 kV/cm.