I. Product Overview
The 20/24kV fully cold-shrink three-core outdoor terminal is a cold-shrink accessory specifically designed for outdoor terminals of 20/24kV three-core power cables. Made of high-performance silicone rubber, it relies on its own elastic shrinkage to achieve insulation, electric field control, sealing, and protection of the cable terminal. It has a built-in umbrella skirt structure to enhance outdoor creepage performance. No heating tools are required, and it is easy to install. It is widely used in outdoor terminal scenarios for 20kV power cables to ensure the safe and stable operation of the cable terminal.
II. Product Characteristics
1. Insulation and electrical properties
- Made of high-quality silicone rubber, it has excellent insulation properties and can effectively withstand the working voltage of 20/24kV systems. Its power frequency withstand voltage and impact withstand voltage performance meet industry standards, ensuring the insulation safety of cable terminals.
- With its own stress control structure, it can effectively and uniformly distribute the electric field at the cable terminal, avoid partial discharge caused by electric field concentration, and improve the long-term operational reliability of the terminal.
- After cold shrinkage, it can fit tightly with the cable body to form a continuous and reliable sealed structure, preventing moisture, rainwater, dust, and oil from entering the cable terminal. It has excellent moisture-proof, waterproof, anti-fouling, and anti-salt spray performance, and IP68 protection.
- The terminal has a built-in umbrella skirt structure, which effectively improves the outdoor creepage distance, enhances the anti-pollution flashover and anti-wet flashover performance, and is suitable for harsh outdoor environments.
2. Installation and Construction Characteristics
- With its fully shrinkable design, it requires no open flame or heating tools. Installation is achieved through the elastic retraction of the pre-expanded diameter, making the installation process safe and convenient, with no fire hazards, and suitable for special construction scenarios such as outdoor and explosion-proof applications.
- The complete set includes all the accessories needed for terminal fabrication (insulating tubes, stress tubes, sealant, installation tools, stripping rulers, etc.), eliminating the need to purchase additional accessories during construction, significantly shortening terminal fabrication time and reducing construction costs.
- After installation, the terminal has a neat and aesthetically pleasing appearance, without the uneven shrinkage, bubbling, or deformation issues common with heat shrink products. It exhibits good consistency and facilitates subsequent maintenance and inspection.
3. Environmental and Weather Resistance
- With excellent weather resistance, it can adapt to a wide temperature range of -40℃ to +90℃. The elasticity and insulation properties of silicone rubber do not decrease under high and low temperatures, and there is no risk of cracking, embrittlement or deformation. It is suitable for various scenarios such as outdoor, underground and cable trench.
- It is anti-aging, anti-ultraviolet, and resistant to ozone corrosion. It can be exposed to the outdoor environment for a long time and has a service life of more than 20 years. It is maintenance-free and reduces the cost of operation and maintenance.
- It is resistant to chemical corrosion and can adapt to harsh environments such as humidity, dust, salt spray, and mild acid and alkali. It has no risk of corrosion or degradation and is suitable for industrial and mining enterprises, coastal areas and other scenarios.
4. Mechanical and Adaptation Characteristics
- Silicone rubber materials have high mechanical strength, are tear-resistant and tensile-resistant, and can withstand mechanical stress during construction and operation without the risk of breakage or cracking.
- It is compatible with 20/24kV three-core power cables, covering common cross-sectional specifications, and has strong versatility, making it suitable for installation scenarios such as outdoor poles, box-type substations, and cable wells.
- The terminal has a compact structure and small size, making it suitable for installation in narrow outdoor spaces without any space limitations.
III. Technical Parameters
| Parameter categories | project | Technical indicators |
| Electrical parameters | Applicable system voltage | 20/24kV AC |
| Rated voltage | 24kV | |
| Power frequency withstand voltage (5min) | 65kV, non-breakdown | |
| Impact resistance (peak) | 125kV, non-breakdown | |
| Insulation resistance | ≥1000MΩ | |
| Partial discharge quantity | ≤5pC (at 1.5 times rated voltage) | |
| Structural and material parameters | Main material | silicone rubber |
| Applicable cable core count | Three-core | |
| Applicable cable cross-section | 25mm²~400mm² (select according to specifications) | |
| Protection level | IP68 | |
| Structural form | Fully retractable outdoor terminal (complete set, with umbrella skirt) | |
| Environmental parameters | Applicable altitude | ≤2000m (Customization available for high altitudes) |
| Ambient temperature | -40℃/ +90℃ (operating temperature), -40℃/ +70℃ (storage temperature) | |
| relative humidity | ≤100% (no condensation) | |
| Seismic resistance level | Level 8 | |
| Implementation Standards | GB/T 12706 “Extruded insulated power cables and accessories with rated voltage of 1kV (Um=1.2kV) to 35kV (Um=40.5kV)” and IEC 60840 “Test methods and requirements for extruded insulated power cables and accessories with rated voltage of 30kV (Um=36kV) and above to 150kV (Um=170kV)”. |
IV. Product Composition List
| Serial Number | name | use |
| 01 | Cold shrink terminal insulation body (with umbrella skirt) | Provides cable termination main insulation, outdoor protection and creepage distance enhancement |
| 02 | Cold shrink insulation tubing | Cable phase insulation layer protection and insulation |
| 03 | Cold shrink sealing tubing | Cable termination moisture-proof, waterproof, and dirt-proof sealing |
| 04 | Three-core branch gloves | Insulation and sealing at the three-core branch of the cable |
| 05/06 | Installation accessory box (sealing glue/cleaning agent) | Clean cable surface and seal terminal interface |
| 07 | Metal pressure ring | Fixed terminal and cable body |
| 08 | Woven copper strip | Cable terminal grounding connection |
| 09 | Rain skirt/umbrella skirt (outdoor use only) | Enhanced terminal creepage distance and improved outdoor anti-pollution flashover performance |
| 10 | Installation instructions/process card | Terminal manufacturing and construction guidance |
| 11 | Sandpaper/Cleaning cloth | Cable surface grinding and cleaning |
| 12 | Insulating tape / Semi-conductive tape | Terminal interface insulation and electric field control |
| 13 | Protective gloves/goggles | Construction safety protection |
| 14 | Installation tools (measuring tape, utility knife, wire strippers, etc.) | Cable stripping and terminal installation |
| 15 | Cable stripper | Precise measurement of cable stripping length ensures process compliance. |
| 16 | Quality Certificate/Inspection Report | Product quality certification documents |
V. Scope of Application
- Applicable voltage level : 20/24kV AC power cable system.
- Applicable scenarios :
- Fabrication of outdoor terminals for 20kV three-core power cables;
- Cable terminals for outdoor applications such as outdoor poles, prefabricated substations, cable wells, and power distribution rooms;
- Cable terminals for special construction scenarios such as explosion-proof and fire-prohibited environments;
- Outdoor cable terminals in harsh environments such as dampness, dust, and salt spray.
- Function and application : Provides insulation, electric field control, sealing and protection for outdoor terminals of 20/24kV three-core power cables, prevents moisture, rain and dust from entering the cable terminal, uniformly distributes the electric field at the terminal, improves the terminal’s anti-pollution flashover and anti-wet flashover performance, ensures the safe and stable operation of the cable terminal, and avoids leakage, short circuit and fault tripping accidents caused by terminal insulation failure, electric field concentration, poor sealing and pollution flashover.
VI. Usage Conditions
1. Normal operating conditions
- Altitude: ≤2000m;
- Ambient temperature: -40℃ to +90℃; cable operating temperature shall not exceed the conductor’s long-term allowable operating temperature.
- Relative humidity: ≤100% (no condensation);
- Environmental conditions: No corrosive gases, no flammable or explosive media, no severe vibration or impact;
- Installation method: cold shrink installation. Simply pull out the support core wire to complete the shrinkage. The installation space must meet the bending radius requirements of the cable terminal.
2. Special usage conditions (customization required)
- The altitude exceeds 2000m;
- The ambient temperature exceeds the range of -40℃ to +90℃;
- Severely polluted, salt spray, and chemically corrosive environments;
- High vibration and high impact conditions;
- Scenarios requiring non-standard cable cross-sections, special creepage distances, and protection levels.
VII. Installation and Maintenance
1. Installation Requirements
- Before installation, check the product appearance. The silicone rubber terminals should be free of cracks, damage, and bubbles. The support core wires should be intact and free of deformation. All accessories should be complete and undamaged.
- Cut the cable according to the cable terminal manufacturing process. The cutting length must meet the terminal specifications. Avoid damaging the cable insulation layer during the cutting process. After cutting, use a cleaning agent to clean the cable surface to remove oil, dust, and semi-conductive layer residue, and ensure that the surface is dry and clean.
- Install the cold shrink branch glove, insulating tube, stress tube, terminal body and outdoor rain skirt in sequence. After adjusting the position, slowly pull out the support core wire to make the terminal shrink evenly and ensure that each component fits tightly with the cable body without deviation, air bubbles and wrinkles.
- After installation, connect the grounding copper strip according to the process requirements, check that the terminal grounding connection is reliable, and confirm that the terminal shrinks evenly, without damage or gaps, and the installation is complete.
2. Maintenance Requirements
- Regularly inspect the appearance of the terminal. The silicone rubber terminal should be free of cracks, damage, discharge marks, and dirt accumulation. The rain skirt should be intact and undamaged. The terminal should be tightly attached to the cable without looseness or gaps.
- Regularly test the terminal insulation resistance and partial discharge to ensure that the performance meets the requirements and to promptly identify potential insulation hazards.
- Clean the terminal surface to remove accumulated dust and dirt, keep the terminal surface dry and clean, avoid oil and chemical corrosion, and regularly check the rain skirt for integrity to prevent flashover.
- If the terminal shows abnormalities such as cracks, damage, discharge, excessive insulation resistance, or damaged rain skirt, the terminal must be replaced in time. It is strictly forbidden to operate the terminal with defects.
VIII. Precautions
- The product must be installed, debugged, and maintained by professional electrical personnel with high-voltage cable terminal manufacturing qualifications. Operation by non-professional personnel is strictly prohibited.
- The product must be used with 20/24kV power cables of the corresponding cross-section and number of cores. It is strictly forbidden to use cables of different specifications, otherwise it will lead to insulation and sealing failure and cause safety accidents.
- The product must not be disassembled or modified without authorization, otherwise the warranty and safety guarantee will be lost. It is strictly forbidden to forcibly stretch or cut the terminal and rain skirt to avoid damaging the silicone rubber material.
- During installation, cables must be stripped and components installed according to process requirements to avoid damaging the cable insulation layer. Support core wires must be pulled out slowly to avoid uneven contraction or misalignment at the terminals. The installation position of the rain skirt must meet process requirements to ensure that the creepage distance meets the standards.
- When storing, it should be placed in a dry, ventilated, and cool environment, avoiding direct sunlight, high temperature, humidity, and compression. It is strictly forbidden to contact with sharp objects that may damage the terminal and rain skirt. The support core wire must be kept intact to avoid deformation.
- During operation, the terminal status needs to be checked regularly to prevent the terminal from being squeezed or bumped by external forces, thus preventing damage to the terminal, failure of the seal, and damage to the rain skirt.
IX. Model Description
| Model Identification | meaning |
| 20/24kV | Applicable system voltage levels: 20/24kV power cables |
| Total cold shrink | Installation method markings, fully shrinkable design. |
| Three-core | Compatible with cable core count markings, three-core cable |
| outdoor | Install scene signage; outdoor terminal (with umbrella skirt). |
| XXmm² | Compatible with cable cross-section markings, such as 70mm², 120mm², 240mm², 400mm², etc. |
10. Implementation Standards and Certification
- International Standard: IEC 60840 “Test methods and requirements for extruded insulated power cables and their accessories with rated voltages of 30kV (Um=36kV) and above up to 150kV (Um=170kV)”;
- National Standard: GB/T 12706 “Extruded Insulated Power Cables and Accessories with Rated Voltages from 1kV (Um=1.2kV) to 35kV (Um=40.5kV)”;
- The product has passed the type test of the National Wire and Cable Quality Supervision and Inspection Center and meets the national power industry standards.
XI. After-sales service
- Product warranty period: 18 months from the date of manufacture, or 12 months from the date of commissioning (whichever comes first).
- During the warranty period, products will be repaired or replaced free of charge if quality issues arise.
- We provide technical support, installation guidance, and customized services (adaptation to special specifications and working conditions).
Document Description
The technical parameters in this manual are based on standard operating conditions. Special operating conditions need to be customized according to actual needs. The final specifications shall be subject to the product technical agreement and type test report.
