There are several different benefits gained by sealing wires and cables within PTFE heat shrink tubing. First, this type of tubing provides excellent electrical insulating properties. Next, the tubing creates a solid sealed barrier to prevent moisture, liquids or other fluids from reaching the cables or wires. Additionally, this barrier also keeps out solid particles and gases, and prevents them from coming into contact with your cables or wires.
Besides being applied to the outside of cables and wires, PTFE heat shrink tubing may also be used as a coating over other various electrical parts and components. When used in this manner, the parts and components receive the same protections experienced by your cables and wires. Further, due to the high temperature needed to melt Teflon® tubing, any object covered in it is protected from exposure in high heat environments.
When working with Teflon® shrink tubing, it is important to understand how it will react once you apply heat to it using an approved heat gun. Once the tubing reaches its shrink temperature, it starts to decrease in size and diameter. During this time, it is important to ensure the heat is evenly distributed, in order for the tubing to shrink neatly and to avoid kinking. The amount of shrinkage achieved does depend upon the shrink ratio and whether there are any restrictions. For example, a section of standard wall tubing with a 2 to 1 shrink ratio in AWG size 10 has a starting minimum inner diameter of 0.191 inches. If it is allowed to fully shrink without any restrictions, the recovered inner diameter is 0.112 inches. It should be noted that it is possible for the tubing to increase in length as it shrinks.