Different samples of poly(vinyl chloride) (PVC) greases were formulated from PVC, triisopropylphenylphosphate plasticizer (TIPPP), and a wax gel (microcrystalline wax and transformer oil) system, together with variable proportions of phenol formaldehyde, stearyl phenol formaldehyde, or stearyl phenol formaldehyde urethane resins. The effect of resin structure on the electrical properties (dielectric constant, dielectric loss, and conductivity) of the PVC-TIPPP-wax gel system was studied to obtain a plasticized PVC grease of high electrical insulation and fire-retarding characters.