I. Product Overview
JY JYM-600 15kV 24kV 600A Insulated Protective Cap is a detachable cable accessory designed specifically for 15kV/24kV (10kV/20kV level) medium-voltage power distribution systems. It features a fully insulated, fully sealed, and touch-accessible structure, compatible with 15kV/24kV 600A standard bushings/interfaces. It provides insulation, sealing, and grounding protection for idle or spare cable interfaces, effectively preventing accidental contact, moisture, and dirt accumulation, while also releasing induced voltage. Widely used in ring main units, prefabricated substations, cable branch boxes, and other equipment, it is a crucial accessory for ensuring interface safety in medium-voltage power distribution systems.
II. Product Characteristics
1. Insulation and protective properties
- Made of high-purity EPDM ethylene propylene diene monomer rubber through integral injection molding, it has no seams or air gaps, excellent insulation performance, can withstand the rated voltage of 15kV/24kV system and short-time overvoltage, meets the operating requirements of the maximum working voltage of 17.5kV/24kV, and has sufficient insulation margin.
- With a built-in optimized electric field structure, the electric field is evenly distributed, effectively suppressing partial discharge. There is no risk of electrical erosion or breakdown during long-term operation, and the partial discharge amount is ≤10pC (below 1.5U₀).
- It comes with a grounding lead, which can achieve reliable grounding, effectively release the interface induced voltage, eliminate the risk of static electricity, and ensure operation and maintenance safety.
- The fully sealed structure design and IP67 protection rating prevent moisture, dust, and foreign objects from entering the interface, avoiding insulation degradation caused by moisture and dirt accumulation.
2. Structural and Safety Features
- The fully insulated, touchable structure has high outer insulation strength, allowing direct contact with the outer casing during operation without the risk of electric shock and eliminating the safety hazards of accidental contact with live interfaces.
- The standardized interface design is compatible with 15kV/24kV 600A standard bushing sockets/elbow type connectors, making installation convenient. It can be directly inserted into the interface without additional tools.
- It features a built-in anti-detachment structure and operating ring, which prevents loosening and falling off after installation. It is also compatible with a dedicated insulated operating rod, enabling live plug-in and unplugging operations and improving maintenance convenience.
- The design prevents mis-insertion, with a unique interface size that can only be used with the corresponding interface specification, eliminating the risk of incorrect installation.
3. Environmental and Weather Resistance
- It has excellent weather resistance and can adapt to a wide temperature range of -40℃ to +90℃. The elasticity and insulation properties of the rubber do not decrease under high and low temperatures, and there is no risk of cracking or embrittlement. It is suitable for various outdoor and indoor scenarios.
- It is moisture-proof, waterproof, stain-proof, and salt spray-proof, and can operate stably for a long time in harsh environments such as underground, damp, and dusty conditions, and is not afraid of rain or condensation.
- It is resistant to aging, ultraviolet rays, and ozone corrosion, with a service life of over 30 years. It requires no maintenance and reduces subsequent operation and maintenance costs.
4. Mechanical and Adaptation Characteristics
- It has high mechanical strength, is impact and vibration resistant, and can withstand mechanical stress during transportation, installation and operation without deformation or damage risk. Its seismic resistance level reaches level 8.
- It is compatible with 15kV/24kV 600A standard cable accessory interfaces and can be interchanged with bushings, elbow joints and surge arresters of the same specifications, with strong compatibility.
- The interface is standardized and conforms to IEEE 386 and relevant domestic standards, and can be adapted to the interfaces of mainstream 15kV/24kV power distribution equipment.
III. Technical Parameters
| Parameter categories | project | Technical indicators |
| Rated electrical parameters | Applicable system voltage | 10kV/20kV (maximum operating voltage 17.5kV/24kV) |
| Rated current rating | 600A (adapter interface current rating) | |
| Power frequency withstand voltage | 42kV/5min (15kV dry test), 65kV/5min (24kV dry test), no breakdown, no flashover. | |
| Lightning impulse withstand voltage | 95kV (15kV peak) and 125kV (24kV peak), no breakdown and no flashover. | |
| Partial discharge quantity | ≤10pC (below 1.5U₀) | |
| Grounding lead specifications | Copper braided wire, ≥4mm², length can be customized. | |
| Structural and material parameters | Main material | EPDM (ethylene propylene diene monomer) rubber (insulation layer), tin-plated copper (grounding terminal) |
| Protection level | IP67 | |
| Interface Standard | 15kV/24kV 600A American standard cable accessory interface | |
| grounding method | It comes with a grounding lead and can be directly grounded. | |
| 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 | IEEE 386, GB/T 12706, GB/T 11022, DL/T 404 |
IV. Scope of Application
- Applicable voltage levels : 10kV/ 15kV/20kV/ 24kV AC medium voltage power distribution systems, compatible with cable accessory interfaces with a maximum operating voltage of 17.5kV/24kV.
- Applicable equipment scenarios :
- Idle/standby interfaces of power distribution equipment such as 15kV/24kV ring main units, prefabricated substations, cable branch boxes, and American-style prefabricated substations;
- Temporarily unused cable terminal interfaces in cable lines are used for insulation, sealing, and grounding protection;
- Urban power distribution network cable lines, power distribution systems of industrial and mining enterprises, and power distribution interfaces for new energy (photovoltaic/wind power) booster stations;
- Safety protection for equipment interfaces in various scenarios such as indoor/outdoor power distribution rooms, underground utility tunnels, and cable tunnels.
- Function and Purpose : To provide insulation, sealing, and grounding protection for idle/standby 15kV/24kV 600A cable accessory interfaces, prevent accidental contact, moisture, and dirt accumulation, eliminate induced voltage, and ensure the safety of power distribution system interfaces.
V. Usage Conditions
1. Normal operating conditions
- Altitude: ≤2000m;
- Ambient temperature: -40℃~+90℃; equipment operating temperature complies with relevant standards.
- Relative humidity: ≤100% (no condensation);
- Environmental conditions: No corrosive gases, no flammable or explosive media, no severe vibration or impact;
- Installation method: Compatible with standard 15kV/24kV 600A interface, horizontal or vertical installation is acceptable, and the installation space must meet the operation requirements.
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;
- Non-standard interface specifications and special grounding requirements.
VI. Installation and Maintenance
1. Installation Requirements
- Before installation, inspect the product appearance for cracks, damage, bubbles, and undamaged insulation surfaces; check that the grounding lead is intact and free of rust, and that all accessories are complete.
- Clean the surface of the interface to be installed, removing oil, dust, and foreign objects, and ensure that the interface is dry and clean.
- Apply a special silicone grease lubricant evenly to the inner wall of the insulating cap interface to avoid damaging the insulation layer during installation.
- Slowly push the insulating cap into the interface to ensure it is fully in place and lock the anti-detachment structure; connect the grounding lead to the grounding grid, and the grounding resistance should be ≤4Ω.
- After installation, check that the insulating cap is securely installed, without looseness or tilting, and that the grounding connection is reliable.
2. Maintenance Requirements
- Regularly inspect the appearance of the insulating cap; check for cracks, discharge marks, and dirt accumulation, and ensure the grounding lead is securely connected without looseness.
- Regularly test the insulation resistance to ensure that the performance meets the requirements and to detect potential faults in a timely manner.
- Clean the surface of the insulating cap to remove accumulated dust and dirt, keep the insulating surface dry and clean, and avoid corrosion from oil and chemicals.
- If the insulating cap shows any abnormalities such as cracks, damage, or loosening, it must be stopped immediately and replaced. Operation with defects is strictly prohibited.
- Special insulated tools must be used for inserting and removing insulating caps. It is strictly forbidden to operate live interfaces with bare hands. Power distribution safety regulations must be strictly followed during operation.
VII. Precautions
- The product must be installed, debugged, and maintained by professional electrical personnel with medium-voltage power distribution construction qualifications. Operation by non-professional personnel is strictly prohibited.
- The product must be used with the corresponding interface specifications. It is strictly forbidden to use interfaces of different voltage or current levels, otherwise it will lead to insulation failure and safety accidents.
- Insulating caps must not be disassembled or modified without authorization, otherwise the warranty and safety guarantee will be lost. It is strictly forbidden to use non-specialized tools to forcibly install or remove them.
- The grounding of the insulating cap must be reliable, with a grounding resistance of ≤4Ω; otherwise, the induced voltage cannot be effectively released, posing a safety hazard.
- 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 insulation layer.
- When plugging or unplugging insulating caps while the circuit is energized, it is essential to strictly adhere to power distribution safety regulations, take appropriate safety precautions, and strictly prohibit any unauthorized operations.
VIII. Model Description
| Model Identification | meaning |
| JY | Product series code |
| JYM | Insulating cap series code |
| □ | Voltage levels (15/24, representing 15kV/24kV respectively) |
| 600 | Adapter interface current rating |
| Insulated Protective Cap | Insulating protective cap, standard interface protection component with grounding wire |
IX. Implementation Standards and Certification
- International Standard: IEEE 386 “Medium Voltage Detachable Cable Connector Standard”;
- National standards: GB/T 12706 “Extruded insulated power cables and accessories with rated voltage of 1kV (Um=1.2kV) to 35kV (Um=40.5kV)”, GB/T 11022 “Common technical requirements for high voltage switchgear and controlgear standards”, DL/T 404 “3.6kV~40.5kV AC metal-enclosed switchgear and controlgear”;
- The product has passed the type test of the National High Voltage Electrical Apparatus Quality Supervision and Inspection Center and meets national electrical safety standards.
X. 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.