High dielectric and resistivity properties make polyester heat shrink tubing an effective electrical insulation material that adds little dimension because of its ultra-thin walls. It can be used over needles to protect the surface of the skin from being burned during electrical stimulation. It is also used effectively to cover electrical components and insulate wiring on catheters and other devices. Some manufacturers are using polyester heat shrink tubing over metal shafts for electrical insulation. It replaces a coating process that was adopted before polyester shrink tubing was available. They could not find any other tubing with a thin enough wall for this application. Using the polyester greatly reduces the chance of pin holes that can develop in coated surfaces.
Photo 1. Black polyester shrink tubing covers a needle (right), leaving only the tip exposed. Electrical wires (left and middle) are covered with clear polyester tubing for insulation.
The key advantages of using polyester (PET) tubing as an electrical insulator are: