I. Product Overview
The 26/35kV fully cold-shrink three-core indoor terminal is a cold-shrink accessory specifically designed for indoor terminals of 26/35kV 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. No heating tools are required, and installation is convenient. It is widely used in indoor terminal scenarios for 35kV 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 26/35kV 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 shrinking and retraction, it can fit tightly with the cable body to form a continuous and reliable sealed structure, preventing moisture, dust and oil from entering the cable terminal. It has excellent moisture-proof, waterproof and anti-fouling performance and IP68 protection.
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. It is suitable for special construction scenarios such as indoor and explosion-proof applications.
- The complete set includes all the accessories needed for terminal fabrication (insulating tubes, stress tubes, sealant, installation tools, etc.), eliminating the need for additional parts 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 a variety of indoor scenarios.
- It is resistant to aging, ultraviolet rays, and ozone corrosion, with a service life of over 20 years. It requires no maintenance and reduces subsequent operation and maintenance costs.
- It is resistant to chemical corrosion, can adapt to humid and dusty environments, has no risk of corrosion or degradation, and is suitable for industrial and mining enterprises, commercial buildings 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 26/35kV three-core power cables, covering common cross-sectional specifications, with strong versatility, and suitable for installation scenarios such as indoor switch cabinets, power distribution rooms, and prefabricated substations.
- The terminal has a compact structure and small size, making it suitable for installation in narrow indoor spaces without any space limitations.
III. Technical Parameters
| Parameter categories | project | Technical indicators |
| Electrical parameters | Applicable system voltage | 26/35kV AC |
| Rated voltage | 35kV | |
| Power frequency withstand voltage (5min) | 95kV, non-breakdown | |
| Impact resistance (peak) | 200kV, 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 refrigerated indoor terminal (complete set) | |
| 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 | Provide main insulation and protection for cable terminals |
| 02 | Cold shrink insulation tubing | Cable phase insulation layer protection and insulation |
| 03 | Cold shrink sealing tubing | Cable termination moisture-proof and waterproof 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 | Insulating tape/Semi-conductive tape | Cable terminal electric field control and insulation assistance |
| 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 | Quality Certificate/Inspection Report | Product quality certification documents |
V. Scope of Application
- Applicable voltage level : 26/35kV AC power cable system.
- Applicable scenarios :
- Fabrication of indoor terminals for 35kV three-core power cables;
- Cable terminals for indoor applications such as power distribution rooms, switch cabinets, prefabricated substations, industrial and mining enterprises, and commercial buildings;
- Cable terminals for special construction scenarios such as explosion-proof and fire-prohibited environments;
- Indoor cable terminals in humid and dusty environments.
- Function and Purpose : To provide insulation, electric field control, sealing and protection for indoor terminals of 26/35kV three-core power cables, prevent moisture and dust from entering the cable terminals, uniformly distribute the electric field at the terminals, ensure the safe and stable operation of the cable terminals, and avoid leakage, short circuit and fault tripping accidents caused by terminal insulation failure, electric field concentration and poor sealing.
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 and special 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, and terminal body in sequence. After adjusting the position, slowly pull out the support core wire to make the terminal shrink evenly, ensuring that each component fits tightly with the cable body without any offset, air bubbles, or 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 terminal should fit tightly with 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 dust and dirt, keep the terminal surface dry and clean, and avoid corrosion from oil and chemicals.
- If a terminal exhibits abnormalities such as cracks, damage, discharge, or excessive insulation resistance, it must be replaced promptly. Operation with defects is strictly prohibited.
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 26/35kV 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 end 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.
- 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. The supporting core wire must be kept intact to avoid deformation.
- During operation, the terminal status needs to be checked regularly to avoid external pressure or collision, and to prevent terminal damage or sealing failure.
IX. Model Description
| Model Identification | meaning |
| 26/35kV | Applicable system voltage levels: 26/35kV power cables |
| Total cold shrink | Installation method markings, fully shrinkable design. |
| Three-core | Compatible with cable core count markings, three-core cable |
| Indoor | Installation scene identification, indoor terminal |
| XXmm² | Compatible with cable cross-section markings, such as 70mm², 120mm², 240mm², 400mm², etc. |
X. 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.
Appendix: Product outline diagram
