Heat Shrink Tubing For Electrical, Automotive, and Industrial Use

Insulation, strain relief, and environmental protection are all vital to implement when planning out electrical schemes, considering that any small vulnerability could degrade performance. Perhaps the most easy-to-use option to achieve these layered requirements is heat shrink tubing, a polymer-based product that contracts to a smaller diameter when controlled heat is applied.

Through this function, it can seamlessly reinforce connection points, guard underlying cables from abrasion or contaminants, bundle multiple wires together, and limit the potential for short circuits. To help you adequately apply this useful tool in your own projects, this blog will explore common heat shrink tubing materials and their forms before taking a look at some of its applications in general electrical, automotive, and industrial setups.ZALKaLKqwerty

Standard Polymer Variants

Heat shrink tubing is capable of contracting due to its polymer base being cross-linked during production, creating stable chemical bonds between individual polymer chains. This may be achieved through a catalyst blended into the material or an electron beam accelerator that applies radiation after the tubing is extruded.

Following either method, the tube is then heated, mechanically expanded, and rapidly cooled while it is retained in its larger size. When heat is later reintroduced by the end user, the polymer chains gain enough mobility to uniformly relax back to their original configuration. 

With this being said, there are a few different polymers employed for their unique properties.

Polyolefin

Polyolefin is known for its:

• Good dielectric strength and insulation for most low- to medium-voltage applications.
• Resistance to basic fluids and mild chemicals.
• Operating temperature ranges starting at -67°F to approximately 248-275°F, depending on formulation.

Fluoropolymer

• Fluoropolymers like PTFE or FEP are a step up from polyolefin, displaying:
• High thermal thresholds exceeding 500°F.
• Excellent tolerance to fuels, solvents, and corrosive agents.

Elastomeric Heat Shrink Materials

Elastomeric heat shrink tubing is a general category that uses rubber-like polymers to present greater flexibility, allowing them to accommodate constant vibration, mechanical movement, or other stressful conditions without failing as easily. The materials under this umbrella include:

• EPDM: EPDM is valued for being impervious to weathering and ultraviolet exposure, as well as its ability to remain flexible across wide temperatures.
• Silicone Rubber: Silicone retains flexibility in both elevated and low-temperature areas, although it is more often chosen for hot areas.
• Neoprene (Polychloroprene): Neoprene is durable and known for tolerating oil and chemical exposure well.

PVC

PVC heat shrink tubing does not offer nearly the same robustness as any of the previous options, but it is still a staple in consumer electronics and light-duty applications for its cost-effectiveness. More than that, it has the benefits of:

• Minimal lengthwise shrinkage, maintaining almost the same initial end-to-end coverage once contracted.
• Excellent insulation.
• Inherent flame retardancy, as PVC is naturally self-extinguishing.

Tube Sizing and Other Characteristics

Shrink Ratios

Heat shrink tubing is available in ratios like 2:1, 3:1, and 4:1, representing the expanded diameter relative to its fully recovered diameter. Larger ratios are better for accommodating differently-sized joints or irregular shapes so the tubing can easily fit over, but using a tube that is far too large can impair insulation or strain relief. Conversely, picking tubing too small for the application could cause unfavorable thinning that weakens the assembly.

Thin-Wall vs. Heavy-Wall

Thin-wall tubing is fit for general-purpose insulation and space-constrained assemblies, offering flexibility and a narrow profile. However, areas where abrasion, impacts, chemical exposure, or other such harsh conditions are anticipated will need heavy- and medium-wall tubing options.

Dual-Wall Tubing

In installations where a mechanical fit alone would be insufficient to prevent degradation, dual-wall heat shrink tubing is the gold standard. This subtype has an internal layer of thermoplastic adhesive or sealant that melts during the heating process, creating an airtight, IP-rated barrier that blocks contaminants from reaching sensitive junctions and stops underlying parts from pulling out. 

Industry-Specific Applications for Heat Shrink Tubing 

Electrical Systems

For standard electrical infrastructure that is enclosed or otherwise located in a controlled environment, the primary goals are to achieve insulation and flame retardancy that are in line with enforced UL 224 or VW-1 safety ratings. Here, heat shrink tubing is often used to:

• Insulate soldered or crimped joints within control panels.
• Reinforce the transition points on ring, fork, or blade connectors.
• Keep wires neatly routed and limit chafing.

Automotive Systems

Automotive systems face persistent vibration and are prone to contact with fuel, oil, brake fluid, rain, or road salt. In some areas, heat radiating off the engine or exhaust manifolds also adds additional strain. These concerns make dual-wall tubing and thicker variants the industry standard, utilized for tasks like:

• Encapsulating wiring harness splices to create a permanent moisture barrier.
• Providing strain relief for delicate sensor and actuator leads, especially those located near high-heat assemblies.
• Protecting heavy-gauge battery cables and EV high-voltage lines from abrasion.

Industrial Environments

Industrial facilities are vast and varied in their stressors, so heat shrink tubing is found in many forms to fit diverse systems. Some of its uses might include:

• Protecting terminations on manufacturing equipment from degradation caused by oils, coolants, or industrial solvents.
• Supporting flexible cable assemblies in robotics or pick-and-place machinery where cables endure millions of high-speed flex cycles.
• Insulating low-voltage signal wiring in PLC and SCADA systems to maintain signal purity.

Source Heat Shrink Tubing from ASAP Components

Ultimately, heat shrink tubing is a practical solution for basic protection tasks, with many materials, shrink ratios, and constructions to choose from to fit distinct operating demands. If you are in the market for any form of heat shrink tubing, ASAP Components has you covered with options from reputable manufacturers.

Moreover, we carry thousands of electrical connectors, board-level components, aviation parts, and beyond, making us a convenient one-stop shop for all maintenance and repair needs. To learn more about our high-quality inventory offerings and competitive procurement solutions, be sure to explore our website and connect with our experts at your earliest convenience.