How Do You Select the Appropriate Riple Layer Heat Shrinkable Tubing for Medium-Voltage Cable Joints?

Purchasing riple layer heat shrinkable tubing is not "you can buy it just because the size is right." The true selection requires also considering the voltage class of the cable and joint, the maximum outer diameter of the joint, the shrunk size, the coverage length, as well as insulation, stress control and long-term thermal cycle adaptability. When purchasing, the joint structure and actual installation size should be confirmed first, and then appropriate specifications should be selected based on product test data, rather than simply matching according to cable cross-section or nominal voltage.

Confirm the Voltage Level of the Cable Connector First.

The primary selection condition for medium voltage cable joints is electrical grade.

IEC 60502-4:2023 puts forward corresponding requirements for type testing of cable accessories in the range of 6 kV (Um 7.2 kV) to 30 kV (Um 36 kV). Therefore, when purchasing, we cannot just look at the general description of "medium voltage cables". It is also necessary to confirm the actual voltage level of the project and the cable and accessory standards adopted.

For example, CCMT's riple layer heat shrinkable tubing is designed for voltage classes of 6 - 36 kV and can be used for insulation treatment and partial discharge control needs of power cable joints up to 42 kV.

Therefore, it is recommended to provide at least:

· Cable voltage level

· Cable structure and outer diameter

· Maximum outer diameter of joint

· Length of joint to cover

· Relevant standards or technical specifications adopted by the project

In this way, suppliers can further confirm product specifications and recommend more suitable products.

Select the Size Based on the Maximum Outer Diameter of the Joint Rather Than Simply Based on the Outer Diameter of the Cable.

After the cable joint is installed, its maximum outer diameter is usually different from the original cable outer diameter. If you only select heat shrink tubing based on the outer diameter of the cable itself, problems such as failure to fit the joint, insufficient fit after shrinkage, or insufficient effective coverage may occur.

Therefore, when selecting a model, it is recommended to focus on measuring the maximum outer diameter of the joint, the length to be covered, and the actual transition size at both ends of the cable.

Specifications currently provided by CCMT include:

This series of products also adopts a 2.5:1 shrinkage ratio, which supports specification confirmation and shrinkage ratio customization based on the actual cable and joint structure. Therefore, when purchasing in bulk, it is recommended not to only provide the "cable model", but to directly provide the supplier with the maximum outer diameter and covering length of the joint, which is more conducive to quick confirmation of specific specifications.

Not Only Look at the Contraction Ratio, But Also Focus on Long-Term Resilience.

During cable operation, it will be affected by load changes and temperature changes, and the insulation layer may undergo repeated thermal expansion and contraction. ‍‌‍‍‌ If the external material is not tough and stretchy enough, issues such as the interface pressure getting lower and the opening getting larger might appear over time after repeated usage. ‍‌‍‍‌ When purchasers choose riple layer heat shrinkable tubing, they should pay attention to whether the product adopts a cross-linked thick-walled structure and a material system with continuous recovery capabilities.

Taking CCMT's products as an example, it adopts a cross-linked thick-walled structure and co-extrusion design of semiconductive layer, insulating layer and elastic layer, so that the tube body can continue to maintain a certain radial restoring force after shrinking, and at the same time adapts to the cable insulation layer due to temperature changes. size changes. This is also one of the important differences between three-layer structure products and ordinary single-layer insulation heat shrink tubing in cable joint applications.

Check the Test Data Instead of Just Looking at "Good Insulation Performance".

For large-scale purchases, the test data provided by suppliers is more valuable than the simple description of "high insulation, aging resistance". For example, CCMT's riple layer heat shrinkable tubing has corresponding test data for different functional layers:

Inner layer:

· Tensile strength ≥6 MPa

· Elongation at break ≥400%

· Dielectric strength ≥15 kV/mm

· Volume resistivity ≥10¹⁴ Ω·cm

· No cracking in-55 ° C low-temperature flexibility test

Intermediate insulation layer:

· Tensile strength ≥10.5 MPa

· Elongation at break ≥400%

· Dielectric strength ≥15 kV/mm

· Volume resistivity ≥10¹³Ω·cm

· No cracking during thermal impact at 200°C/30 min

Outer layer:

· Tensile strength ≥20 MPa

· Elongation at break ≥350%

· Tensile strength ≥16 MPa after aging at 158°C/168 h

· 250°C/30 min thermal impact No cracking, no dripping, no flow

In addition, the thermal aging performance of our products is tested with reference to IEC 216, and the halogen content of the material meets the requirements of IEC 61249-2-21. These data can help buyers judge products from the perspectives of mechanical properties, electrical insulation, heat resistance and long-term use adaptability.

Pay Attention to the Operating Temperature and Actual Installation Temperature of the Product.

"How much temperature can the three-layer heat shrink tube withstand" and "How much temperature is needed for installation" are two different questions. Take our products as an example, with an operating temperature range of-55°C to 105°C and an installation shrinkage temperature of 135 - 150°C.

Therefore, purchasing and installation personnel need to confirm separately:

· Whether the project operating environment is within the product operating temperature range;

· Whether the on-site heating tool can meet the shrinkage temperature specified by the product;

· Whether the joint structure allows uniform heating;

· Whether the heat shrinkable product can completely cover the target area.

Especially in batch engineering projects, product parameters and on-site installation process should be confirmed at the same time. Otherwise,‍‌‍‍‌ if specifications are chosen properly, an inappropriate installation environment might interfere with the ‍‌‍‍‌results.

What Information Is Recommended to Provide to Suppliers at One Time When Purchasing?

If you want to quickly obtain accurate riple layer heat shrinkable tubing specifications, you can provide the following information when making an inquiry:

For‍‌‍‍‌ joints having complicated configurations or not of the industry standard size, physical images, construction drawings and dimensions at location of installation must be ‍‌‍‍‌supplied.

Why Is the Supplier's Testing and Project Experience Worthy of Being Included in Purchasing Judgment?

Rip layer heat shrinkable tubing is a functional material in the cable joint insulation system. Therefore, in addition to product parameters, when purchasing, you should also understand whether the supplier has continuous production and quality control capabilities.

CCMT was established in 1986 and has a production base of approximately 10,000㎡ and 40+ professional production equipment. The monthly supply capacity of heat shrink products is approximately 5 million meters. We have established an ISO 9001:2015 quality management system and carry out quality control of raw materials, production processes and finished products.

In terms of project experience, we have provided relevant heat shrinkable cable accessory products for Hainan Nuclear Power Station, Tianwan Nuclear Power Station, Taishan Nuclear Power Station, Ling 'ao Nuclear Power Station and Fangjiashan Nuclear Power Station.

The significance of this type of information is not to prove that a certain model of product is "naturally suitable for all projects", but to help the purchaser further determine whether the supplier has specification confirmation, quality control, mass production and project supply capabilities.

Conclusion: It Is Recommended to Follow These Four Steps to Confirm the Selection of Medium Voltage Cable Joints.

If the entire procurement process is further simplified and three-layer co-extruded composite heat shrink tubing is selected for the medium voltage cable joint, the following steps can be followed:

1. Confirm the voltage level first

2. Measure the maximum outer diameter and covering length of the joint

3. Check shrinkage ratio, operating temperature and test data

4. Finally confirm the supplier's production and project supply capabilities.

If you are selecting a suitable riple layer heat shrinkable tubing, it is recommended to provide us with the complete cable voltage, connector size and project technical requirements, and we will match the final specifications for you.