Heat Shrink Tubing

Providing Critical Protection for Electrical Connections

Heat shrink tubing is an extruded tube that shrinks in diameter when heated, providing tight protection for wires, cables, harnesses, conductors, terminals, and other components. It safeguards against moisture, wear and tear, and abrasion, and helps in sealing equipment, reducing noise, and organizing cables.

When installed properly, the adhesive or ceiling liner melts as the tubing shrinks, forming a complete seal that flows throughout the application's internal spaces. Heat shrink tubing provides a long-lasting and secure fit and is a semi-permanent protective solution in the sense that it can be removed or replaced if necessary. If you need to remove it, you can cut it away, but it cannot be reused once shrunk.

Heat shrink tubing is constructed from materials such as polyolefin, polyvinyl chloride (PVC), and fluoropolymers like Neoprene®, polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), and Kynar® polyvinylidene fluoride (PVDF). These materials provide excellent insulation, abrasion resistance, chemical resistance, and environmental protection.

Common Types of Heat Shrink Tubing

The following table represents the common types of heat shrink tubing and the leading brands and heat shrink ratios available at LAPP Tannehill. Heat-shrink tubing material, size, color, flexibility, flammability rating, standards/approvals, shrink temperature, and operating temperature all vary per manufacturer.

Types	Description	Applications/Use Cases	Heat Shrink Ratios	Leading Brands
Single Wall	Single wall or ‘thin wall’ tubing, also known as ‘general purpose’ with its outer layer being its only barrier of protection	Prevent short circuits & low voltage electrical faults by shielding exposed wires; noise reduction for pipes; insulation & strain relief for fine gauge wire; unlikely to be exposed to outside elements	2:1, 3:1, 4:1, 1.5:1, 2.5:1	DSG-Canusa, Dunbar, Insultab, Sumitomo Electric, TE Connectivity (Raychem)
Single Wall (SFR)	Single wall tubing made of crosslinked silicone elastomer (produced only by TE Connectivity)	Recommended for projects requiring flexibility, sealing, strain relief, flame-retardancy (chemically treated to resist fire); can be used to protect irregular shapes in wire connections or terminations	1.75:1	TE Connectivity (Raychem)
Dual Wall	Dual wall tubing, also known as ‘adhesive-lined’ tubing, has 2 layers (outer layer of polyolefin & inner layer of hot melt adhesive)	Recommended for chemical resistance & wet/moist applications; provides insulation/ protection from harsh environments (exposure to wind, rain, heat, extreme cold)	2:1, 3:1, 4:1	DSG-Canusa, Dunbar, Sumitomo Electric, TE Connectivity (Raychem)
Medium Wall	Medium wall tubing has a wall thickness of 0.062-0.118 in (1.6–3 mm) after shrinking	Balance of flexibility & durability often used in medium voltage electrical/ mechanical use cases; automotive wiring; industrial equipment for moderate environmental protection	3:1	DSG-Canusa
Heavy Wall	Heavy wall tubing has the thickest wall type with a thickness of 0.123-0.185 in (3.2–4.7 mm) after shrinking	Best mechanical protection against abrasion, sharp edges, impact resistance; for use in commercial projects, long-term insulation, direct burial, & large industrial equipment	3:1, 6:1	DSG-Canusa
Medical Grade Heat Shrink Tubing	Medical-grade heat shrink is designed using polyolefin & fluoropolymers like PTFE, FEP, & PEEK (high-performance plastics with excellent chemical resistance) to withstand sterilization methods, high temperatures, & radiation without degrading	Abrasion protection for catheters, drains, tracheotomy tubes, & medical instruments; insulation in laparoscopic electrosurgical devices; mechanical protection & insulation of highly flexible joints; processing aid for interventional applications	2:1, 3:1, 4:1, 2.5:1	TE Connectivity (Raychem), Zeus
Pre-cut Heat Shrink Tubing	Pre-cut tubing cut to standard lengths per the manufacturer/ distributor	Useful when you need uniform lengths for repeated applications; mass production or assembly line settings; projects that require little to no manual cutting & waste reduction	2:1, 3:1	Varied

Why Use Heat Shrink Tubing?

Heat shrink tubing is an essential component for anyone looking to protect and manage their electrical wire and cables. Here are some key benefits:

Insulation & Protection: It offers excellent electrical insulation, preventing short circuits and protecting wires from damage due to abrasion, moisture, and chemicals.

Strain Relief: By providing a snug fit around wires and connectors, heat shrink tubing reduces stress on connections and prevents wire breakage.

Identification & Organization: Heat shrink can bundle components together to keep them organized and easier to manage while various colors can be used for easy identification.

Repair & Maintenance: Easily repair damaged wires or reinforce weak spots by simply applying heat shrink tubing, extending the lifespan of your cables.

Tips on Choosing Heat Shrink Tubing

Shrink Ratio: Shrink ratio is a measurement of how much heat shrink tubing shrinks in diameter and thickness when heated. For example, a 2:1 shrink ratio means the tubing will shrink to half its original size, while a 6:1 ratio means it will shrink to 1/6th of its original size.

Diameter: Select heat shrink tubing with a pre-shrink diameter that fits over your largest component and a post-shrink diameter that tightly covers the smallest.

Operating Temperature: Ensure the tubing can withstand the operating temperatures of your application.

Flexibility: Select tubing with the appropriate flexibility for your application. More flexible tubing is easier to install around tight bends, while stiffer tubing offers more protection. The thicker the tubing, the less flexibility it will have.

Wall Thickness: Consider wall thickness based on the level of protection needed. Heavy-wall tubing provides better insulation and protection, while single/thin-wall tubing is more flexible.

Longitudinal Shrinkage: This is the amount of heat shrink that shortens when heated, in addition to shrinking in diameter. This is also known as "long change" or "shrinks back". The amount of longitudinal shrinkage depends on the amount of diameter reduction that's allowed. In most cases, the length reduction is less than 10% of the original length.