Correct Use Of Heat Shrink Tubing And Its Application in Wire Harness And Busbar Systems

In the field of electrical connections and wire harness manufacturing, insulation and protection are always the core elements ensuring system safety and reliability. With the rapid development of new energy vehicles, energy storage systems, and industrial electrical equipment, the application of wire harnesses and busbars under high voltage and high current conditions is becoming increasingly common. As a mature and cost-effective insulation and protection material, the correct selection and standardized use of heat shrink tubing are particularly important.

 

 

Heat shrink tubing, also known as heat shrink sleeve or heat shrinkable tubing, is a functional insulating sleeve made of radiation-crosslinked polymer materials. Its core characteristic is that it can radially shrink after being heated, tightly covering the surface of cables, terminals, or busbars, thereby achieving multiple purposes of insulation, protection, sealing, and fixation.

 

Common heat shrink tubing has good flexibility, flame retardancy, and chemical corrosion resistance, and is widely used in electronic equipment wiring protection, wire branch sealing, metal conductor corrosion protection, and structural reinforcement under complex working conditions. For example, in high-voltage systems of new energy vehicles and energy storage busbar systems, heat shrink tubing is often used in conjunction with busbars to form structures similar to Heat Shrink Busbar or Busbar Sleeves Insulation, improving overall insulation levels and environmental adaptability.

 

From a materials perspective, heat shrink tubing mostly uses polyolefin systems, but can also be used in scenarios such as Heat Shrink Tube Polyolefin Busbar, depending on requirements. In some low-voltage or special applications, it may also be used in conjunction with solutions such as PVC Insulation Busbar.

 

Heat shrink tubing typically has clearly defined thermal performance parameters: the initial shrinkage temperature is approximately 70℃, and the full shrinkage temperature is generally not lower than 125℃. According to the withstand voltage rating, it can be divided into low-voltage heat shrink tubing and high-voltage heat shrink tubing, with high-voltage models commonly used for busbar protection and Insulated Busbar systems.

 

 

In actual production and assembly processes, the use of heat shrink tubing should follow standardized procedures to ensure the final insulation and protection effect.

 

First, the appropriate type should be selected based on the dimensions of the object being protected. Accurate measurement of the outer diameter of the cable, wire harness, or busbar is necessary, and the appropriate heat shrink tubing specification should be selected with an inner diameter slightly larger than that of the object to be covered, allowing sufficient space for the shrinkage process.

 

Secondly, the area to be covered must be treated before tubing is applied. Burrs, sharp corners, oil, and impurities on the cable or conductor surface should be removed to prevent puncture of the tubing or affecting the fit during heat shrinking. Maintaining surface cleanliness is fundamental for long-term, reliable protection.

 

When cutting the heat shrink tubing, ensure the cut is smooth, crack-free, and burr-free. Irregular cuts can easily cause stress concentration during heating, leading to the heat-shrink tubing expanding and breaking along the crack direction, affecting overall insulation performance.

After inserting the heat-shrink tubing, it should be adjusted to the correct position. For wire harnesses or busbar structures with bends, the tubing at the bends needs to be properly arranged beforehand to avoid wrinkles or gaps after shrinkage. This is particularly critical in busbar insulation tubing or high-voltage connection structures in new energy applications.

 

During the heating process, a stable heat source such as a hot air gun or oven should be used, and the heat source should be moved evenly. Heating can be applied from one end to the other or diffused from the middle to both ends to ensure proper air expulsion and a tight seal between the heat shrink tubing and the protected object after cooling. This process is crucial for components with extremely high insulation reliability requirements, such as EV Battery Connectors.

 

 

During the heating process, a suitable distance should be maintained between the heat source and the tubing, typically recommended to be 4–5 cm. The heat source should be continuously moved to avoid localized overheating. If the temperature exceeds the material's upper temperature resistance limit, the heat shrink tubing may soften, deform, or even shrink back and fail.

 

The heating angle and path are equally important. It is recommended that the heat source be held at approximately a 45° angle to the tubing surface and moved slowly along the axial direction to ensure even heating of the entire tubing and prevent air bubbles, uneven thickness, or surface burns.

Furthermore, different heat shrink tubings have different shrinkage ratios. The common specification is 2:1, meaning that after full shrinkage, the inner diameter of the heat shrink tubing is approximately half of its original size. Therefore, when selecting a heat shrink tubing, calculations should be performed based on the maximum outer diameter of the object to be covered to ensure a stable fit after shrinkage.

 

Different application scenarios require different types of heat shrink tubing. For straight wire harnesses, a specification close to the outer diameter is usually sufficient; for busbar protection in power plants, electrical cabinets, and energy storage systems, dedicated busbar heat shrink tubing or a busbar insulation sheet should be used; if sealing performance is required, adhesive-backed or waterproof heat shrink tubing should be used.

 

 

As electrical systems develop towards higher voltage, higher power, and higher integration, heat shrink tubing is no longer just a basic insulation material, but an indispensable functional component in wire harness systems and busbar structures. Through proper selection, standardized operation, and correct heating processes, heat shrink tubing can play a long-term, stable role in insulation, protection, and reliable support in electrical connections, providing a solid guarantee for the fields of new energy, power electronics, and industrial automation.