Heat shrink tubing is used in a wide variety of industries to insulate any and all wiring and cable applications. Heat shrink tubing sizes, colors and specifications run the gamut, but no matter what you need it for, the ultimate deciding factor is the shrink ratio.

Understanding Heat Shrink Tubing Sizes

The shrink ratio of heat shrink refers to the amount the tubing must tighten in order to fit snugly around the narrowest part of the cable. The more variation you have in your wiring or cable size, the higher the shrink ratio you will need.

A simple equation to calculate what heat shrink tubing size you need goes like this:

The different types of tubing come in wide-ranging shrink ratios, so no matter what your application is, there should be heat shrink tubing in the corresponding size for your project. The next deciding factor for your heat shrink then, is the application.

Heat Shrink Tubing Buyer’s Guide

We can break heat shrink tubing into four broad categories – single wall, adhesive lined, special purpose and heavy duty. Within each category there are different types of heat shrink tubing that can be used for more specific purposes depending on the application environment.

1. Single Wall Polyolefin Tubing This type of heat shrink tubing is the most universal and widely used, as it is suitable for most general purposes. Each kind of tubing in this category comes in a wide range of diameters, so you will always find the right size for your job. The four primary types of single wall heat shrink, and their corresponding shrink ratios are:
   1. Flexible General Purpose – 2:1
   2. Flame-Retardant – 2:1
   3. Very Flexible – 3:1
   4. Semi-Rigid – 2:1
2. Adhesive-Lined Polyolefin Tubing Products in this category again come in a wide variety of heat shrink sizes, but are designed for more specific applications. Most are good for use in automotive or marine settings and are designed as environmental protection sleeves. The two primary types of adhesive-lined heat shrink and their corresponding shrink ratios are:
   1. Multiple Wall – 2.5:1
   2. Environmental Protection Sleeve – 2:1, 3:1 and 4:1
3. Special Purpose Tubing This category of heat shrink tubing still comes in many sizes, but each type is made of unique materials suited for specialty jobs. This could be high heat settings or a setting where the heat shrink is exposed to oils and chemicals. The five types of specialty tubing and their corresponding shrink ratios are:
   1. Polyvinylidene Fluoride (Kynar) – 2:1
   2. Modified Neoprene – 2:1
   3. Fluoroelastomer (Viton) – 2:1
   4. Polytetrafluoroethylene – 2:1
   5. PVC – 2:1
4. Medium & Heavy Duty Tubing These two variations of tubing come in the larger heat shrink tubing sizes and have higher ratios for more variable applications. They are best suited for use in situations that need flame retardant materials or in environments where they will experience chemicals and abrasion. The two types of heavy-duty tubing and their corresponding ratios are:
   1. Medium-Duty – 3:1
   2. Heavy-Duty – 3:1

As you can see, there is a heat shrink tubing size and material suited for nearly any and all applications. We have a more robust, comprehensive tubing selection guide that highlights more specifications about each type of heat shrink.

If you’re in the market for heat shrink tubing – whether it be a standard, bulk or even a custom order – explore Nelco’s vast catalog of heat shrink tubing. If you’d like to learn more about ordering, please contact one of our representatives.

About the Author

Charlie Nelson

Charlie Nelson is the owner and founder of Nelco Cable Tie Products, which opened its doors nearly 35 years ago. Today, Nelco is one of the largest cable tie and wiring accessory companies in the country, with locations across the United States servicing customers such as NASA, 3M, Boeing, and more.

View Full Bio »