Types of insulation used on automotive wire | American Types of insulation used on automotive wire. There are two main categories of automotive wire – PVC and Cross-Linked. The biggest difference between the two categories is temperature range, as shown below. PVC is created by heating PVC and then extruding it through a die on the stranding. This insulation can be melted with a heat source Amazon: wiring insulation Automotive Wiring Harness Cloth Tape - Maxwel VERSAF51217 Chemical Fiber Cloth High Temp Wire Harness Wrapping Tape for Auto Electrical Wrap, Protection, Insulation 19MM × 25M Pack of 1 Piece 0" 656' Electric Cable Wraps Black PVC High Heat-shrinkable Tubing for Electrical Insulation/Wiring Harness (Pack of 1 Roll) $29 $ 29. 99.