Home > Products > Cable Accessories
Heat shrink joints are elastic insulating sealing fittings used for intermediate splicing/terminal sealing of power cables. The main materials are silicone rubber and high-elasticity EPDM rubber. The entire process requires heating, using a blowtorch or heat gun. The rubber itself shrinks and adheres to the cable.
Cable heat shrink joints are mainly used for intermediate splicing and termination of high and low voltage power cables. They are widely applicable to municipal power distribution, building infrastructure, industrial and mining areas, and outdoor overhead and direct-buried cable projects. After heat shrinking, they tightly wrap the cable connection, achieving insulation sealing, waterproofing, moisture protection, corrosion prevention, isolation from soil and rainwater erosion, and prevention of leakage and short circuits. They are suitable for wiring in switchgear, transformers, motors, and other equipment, improving the stability and service life of the line operation.
• Heat Shrink Connector Body
• Heat Shrink Joint Umbrella Skirt
• Heat Shrink Joint Grounding Wire
• Cable
I. Insulation Electrical Characteristics
1. High Insulation Strength: The heat shrink tubing substrate is mostly cross-linked polyethylene, with high breakdown voltage, effectively isolating phase wires, ground wires, and armor layers, meeting the insulation protection requirements for medium and low voltage cables.
2. Leakage and Arc Resistance: Flame-retardant and anti-corona formulas are added to suppress creepage, suitable for indoor, outdoor, and buried cable joints.
3. Moisture-proof and Dielectrically Stable: Matching hot melt adhesive sealant prevents moisture intrusion, and insulation performance does not degrade even after long-term immersion in water or humid environments.
II. Sealing, Waterproofing, and Moisture-proof Characteristics
1. Hot Melt Adhesive Composite Structure: During heating and shrinking, the hot melt adhesive on the inner wall melts, filling gaps in the cable, metal armor, and copper shielding layer, forming an integrated waterproof sealant layer.
2. Water and Underground Corrosion Resistance: Suitable for buried applications and water-filled cable wells, preventing groundwater and mud from seeping into the cable core, eliminating water ingress and short circuits.
3. Airtight and Dustproof: Completely seals gaps, preventing dust and corrosive gases from entering the joint.
III. Physical and Mechanical Properties of Heat Shrinkable Cables
1. High-Temperature Shrinkage, Room-Temperature Shaping: Shrinks uniformly upon heating with hot air at 70-130℃, recovers its hardness upon cooling, tightly grips the cable body, and fits without gaps.
2. Elastic Buffering: Possesses moderate toughness, allowing it to deform with the cable during thermal expansion and contraction without cracking or delamination.
3. Wear and Impact Resistance: The outer heat-shrinkable sheath resists impacts and dragging abrasion, and is not easily damaged by sand and gravel during construction and backfilling.
4. Crack Resistance and Low Stress: The cross-linked material resists aging, and does not crack despite repeated shrinkage and expansion due to temperature cycles.
IV. Environmental and Aging Resistance
1. High and Low Temperature Resistance: Operating temperature -40℃ to 120℃, does not crack at low winter temperatures, and does not melt at high cable temperatures.
2. Weather Resistance and UV Resistance: Outdoor overhead heat-shrinkable connectors contain UV inhibitors, preventing powdering and cracking under prolonged sun exposure.
3. Chemical Corrosion Resistance: Resistant to acids, alkalis, oils, soil electrolytes, and corrosion from chemical plants and underground pipelines.
4. Long-lasting anti-aging: Service life can reach 20-30 years, requiring minimal maintenance for underground installations.
V. Flame-retardant safety characteristics
Mostly made of flame-retardant cross-linked PE material, self-extinguishing upon contact with open flame, preventing continuous combustion and preventing joint failures from igniting the entire cable, complying with power fire protection regulations.
VI. Construction and compatibility characteristics
1. Easy installation: Only a hot air gun is needed; no complex molds or welding equipment are required, enabling fast on-site construction.
2. Compatible with multiple specifications: Available in single-core, three-core, four-core, five-core, and high/low voltage series, compatible with 0.6/1kV low-voltage and 8.7/10kV high-voltage cables.
3. Layered matching: Includes inner insulation heat shrink tubing, shielding recovery heat shrink tubing, armored grounding heat shrink tubing, and outer sheath heat shrink tubing, achieving integrated insulation, shielding, and waterproofing through layered solutions.
VII. Shielding and Grounding Protection Characteristics
Equipped with semi-conductive heat shrink tubing, it restores the uniformity of the electric field in the copper shielding layer of the cable, eliminates electric field concentration at the joint, and avoids partial discharge and breakdown; the metal armored heat shrink sleeve achieves continuous armored grounding protection.
IEC 60502-4
IEC 60840
IEC 61238-1
IEC 60815
HD 629.1 S1
EN 50393
IEEE Std 48
| Material name | Performance | Parameters |
| Main heat shrink material | Hardness Shore(A) | 84±3 |
| Tensile strength(Mpa) | ≥12 | |
| Shrinkage temperature(℃) | 120-130 | |
| Insulation tube | Volume resistivity(Ω.cm) | ≥1×1014 |
| Breakdown strength(KV/mm) | ≥20 | |
| Radial shrinkage rate | 2.5:1 | |
| Longitudinalshrinkage rate % | ±5 | |
| Industrial frequency long-term pressure(KV/4h) | 2.4 | |
| Work frequency dry state withstand voltage(KV /5min) | 4 | |
| Applicable cable cross section mm² |
Indoor terminal | Outdoor terminal | Intermediate connection | |||
| One-core | Three-cores | One-core | Three-cores | One-core | Three-cores | |
| 50,70,95,120 | NSY-35/1.1 | NSY-35/3.1 | WSY-35/1.1 | WSY-35/3.1 | JSY-35/1.1 | JSY-35/3.1 |
| 150,185,240 | NSY-35/1.2 | NSY-35/3.2 | WSY-35/1.2 | WSY-35/3.2 | JSY-35/1.2 | JSY-35/3.2 |
| 300,400 | NSY-35/1.3 | NSY-35/3.3 | WSY-35/1.3 | WSY-35/3.3 | JSY-35/1.3 | JSY-35/3.3 |
| Project | Parameters | Rating |
| Work frequency dry state withstand voltage(KV/5min) |
105 | No flash-over,no breakdown |
| Work frequency wet state withstand voltage(KV/5min) |
105 | No flash-over,no breakdown |
| Work frequency long-term withstand voltage(KV/4h) |
78 | No flash-over,no breakdown |
| Shock withstand voltage (KV/1.2/50μs±10 times) |
140 | No breakdown |
| DC withstand voltage(KV/15min) | 156 | No flash-over,No Breakdown |
| Partial discharge(KV.PC/1.5uo) | 10 | Pass |
Huili Cable Co., Ltd. (formerly Luohe Huili Cable Co., Ltd. and Luohe Cable Factory) was founded in 1989 and was renamed Huili Cable Co., Ltd. on September 14, 2024. The company's registered capital is RMB 200 million.
