Differences between heat shrin cable joints and cold shrink cable joints

In modern power system cable networks, joints are crucial components, their reliability paramount. Faced with the two mainstream technologies of heat shrink cable joints and cold shrink cable joints, engineers face a decision that goes far beyond simply choosing between hot and cold. The following analysis examines their key differences from three perspectives: core principles, installation techniques, and performance applications.

I. Core Principle: Thermal Drive vs. Elastic Memory

1. Thermal activation principle of heat shrink cable joints

• Materials and Contraction : Based on materials such as radiation-crosslinked polyolefins, the material is pre-expanded and shaped. When heated , the material "remembers" its original shape, generating a strong radialcontraction force.

• Sealing : The shrinkage force squeezes the internal hot melt adhesive to fill the micro gaps on the interface, achieving a tight seal that is waterproof and moisture-proof .

2. Elastic Retraction Principle of Cold Shrink Joint

• Materials and Drive : Highly elastic silicone rubber/EPDM. Pre-expanded and wrapped around the cable support core at the factory. When the core is removed on-site , the rubber naturally retracts due to its inherent high elasticity, securing the cable.

• Sealing method : Mainly relies on the elastic recovery force of rubber to form an interface pressure seal, sually without the need for adhesives.

II. Installation process: flame and skills vs. ready-to-use

1. Installation points of heat shrink cable joints

• Heat source dependence : Professional heat source (spray gun/hot air gun) must be used for uniform heating.

• Skill requirements : High operator proficiency is required, and precise control of temperature and movement speed is required to avoid local overheating or incomplete shrinkage. Application is limited in flammable and explosive environments or in confined spaces .

2. Installation advantages of cold shrink joints

• Convenient and efficient : The core operation only requires pulling out the support core , and no heat source or power supply is required.

• Universal environment : Especially suitable for environments where open flames are prohibited, spaces are small, and humidity is a concern , with fast installation and high quality consistency.

III. Performance and Application Scenarios: Each Has Its Own Strengths

1. Key performance comparison

• Heat shrink cable joints: Hot melt adhesive flows easily onto irregular surfaces, creating a dual "adhesive + mechanical" seal. The cross-linked polyolefin outer sheath provides excellent weather resistance (UV, chemical, and abrasion resistance) , making it suitable for long-term outdoor exposure (overhead and direct burial). This technology has decades of proven application .

• Cold shrink joints : Silicone/EPDM rubber offers excellent hydrophobicity and wide temperature adaptability . The elastic seal is more stable under frequent thermal expansion and contraction, as well as vibration . However, long-term aging performance of the rubber (especially at high temperatures) requires attention.

2. Typical application selection

Heat shrink cable joints main battlefield :

• Medium and high voltage cables (especially 35kV+) have high requirements for mechanical protection and outdoor weather resistance.

• Applications requiring strong resistance to external damage (such as direct burial and extrusion).

• Where cost is sensitive and the environment allows open flame operation , low voltage heat shrink cable joints are widely used in power distribution networks due to their excellent cost performance and reliability .

Advantages of cold shrink joints :

• Flammable and explosive areas (petrochemical, coal mines), places with limited space (work wells, cabinets).

• require quick installation , underwater or extremely humid environments (special type).

Conclusion: Adapting to the scene shows its value

Heat-shrink and cold-shrink cable joints are not substitutes, but rather complementary engineering solutions. Heat-shrink cable joints, with their proven reliability, excellent weather resistance, mechanical protection, and cost-effectiveness in the low-voltage sector（low voltage heat shrink cable joints） , safeguard countless power nodes. Cold-shrink technology, with its flame-free installation, universal environmental compatibility, and easy operation , addresses complex and demanding scenarios.

A wise choice stems from a deep understanding of the project's specific needs (voltage level, environmental conditions, safety requirements, and construction budget). Understanding the core advantages and applicable boundaries of each technology ensures the long-term safe and efficient operation of the cable network, the "lifeblood of electricity."