Hebei Anmei Electrical Equipment Co., Ltd. is one of the most reliable manufacturers and suppliers of indoor porcelain bushing in China, also supports customized service. If you're going to buy high quality indoor porcelain bushing made in China, welcome to get quotation from our factory.
Indoor Porcelain Bushing is a fundamental electrical insulation component widely used in indoor switchgear, metal-enclosed substations, medium-voltage circuit breakers, and transformer applications. Porcelain has been the material of choice for indoor bushings for over a century, offering exceptional dielectric strength, mechanical robustness, and proven long-term reliability. As a critical interface between energized conductors and grounded enclosures, the indoor porcelain bushing must provide reliable insulation while withstanding electrical stresses, thermal cycling, and occasional mechanical impacts in confined spaces. These bushings serve utility companies, industrial facilities, commercial buildings, and railway power systems where safe and reliable power distribution is paramount.
Electrical Ratings
| Parameter | Standard Value |
|---|---|
| Voltage Class | 12 kV – 52 kV |
| Power Frequency Withstand Voltage (1 min) | 28 kV – 140 kV (dry) |
| Lightning Impulse Withstand Voltage (BIL) | 60 kV – 325 kV |
| Continuous Current | 200 A – 4,000 A+ |
| Creepage Distance |
≥ 10 mm/kV (indoor standard)
|
Material Specifications
| Component | Material |
|---|---|
| Insulation Body | High-grade wet-process porcelain, glazed surface |
| Conductor | Copper or Brass, tin-plated or silver-plated as required |
| Flange | Aluminum alloy, cast iron, or steel (tin-plated) |
| Gasket | Oil-resistant rubber (NBR) |
Key Features
Standards Compliance
All Indoor Porcelain Bushings are manufactured in accordance with IEC 60137, IEEE C57.19.01, and GB/T 4109 standards. We also offer compliance with customer-specific specifications and regional standards including CSA, GOST, and NBR. Terminal arrangements and mounting dimensions follow the latest standard revisions to ensure seamless replacement and compatibility.
Premium Porcelain Material
Our porcelain bodies are manufactured using high-purity alumina (Al₂O₃) content exceeding 85%, fired under precisely controlled temperature curves to achieve maximum density and mechanical strength. The glaze coating provides a smooth, non-porous surface that resists contamination buildup and ensures stable electrical performance even in high-humidity indoor environments.
High Mechanical Strength
With cantilever strength exceeding 100 kg and bending moment capacity up to 2,000 N·m, these bushings withstand the mechanical stresses of conductor connections, short-circuit forces, and seismic events. The robust porcelain design ensures integrity even under occasional overload conditions and accidental impact.
Reliable Sealing System
Oil-tight, water-tight construction with NBR gaskets ensures zero leakage at the mounting interface. Helium mass spectrometer leak testing verifies seal integrity, making these bushings suitable for oil-filled transformer and switchgear applications.
Optimized Insulation Design
Scientific shape design with optimized metal and porcelain interface minimizes electrical field stress concentration, reducing the risk of partial discharge and surface tracking. Our bushings achieve partial discharge levels below 10 pC at 1.1 × rated voltage, ensuring long-term operational reliability.
Wide Temperature Range
Designed for indoor service, these bushings operate reliably across a temperature range of -40°C to +105°C, accommodating various climate conditions and equipment operating environments
Common Problem
What is the difference between indoor and outdoor porcelain bushings? Can I use an indoor bushing outdoors?
The primary difference lies in the creepage distance and weather-proofing design. Outdoor bushings have a longer creepage distance (typically ≥ 20 mm/kV for heavily polluted areas) and additional weather sheds to prevent water bridging and contamination flashover in rain, fog, or snow. Indoor bushings have shorter creepage distances (≥ 10 mm/kV) and are not designed for direct exposure to rain or UV radiation. We strongly recommend using outdoor-rated bushings for any exposed outdoor application to ensure safety and reliability.
What is the expected service life of an indoor porcelain bushing, and what maintenance is required?
With proper installation and under normal operating conditions, indoor porcelain bushings can provide 30+ years of reliable service. Maintenance is minimal-primarily routine visual inspections for cracks, chips, contamination, or signs of electrical tracking. The non-porous glazed porcelain surface resists contamination and is easily cleaned with a soft cloth if needed. No scheduled replacement is required unless physical damage or deterioration is observed.
How do you ensure the porcelain does not crack during shipping and installation?
Our porcelain bodies are manufactured with high mechanical strength (cantilever strength >100 kg) and carefully designed for resilience. For shipping, each bushing is individually packed in shock-absorbing foam or wooden crates that meet international export packaging standards. For installation, we provide detailed installation instructions with proper torque specifications to avoid over-tightening, and our technical support team is available to guide your installation team if needed.
Why choose Anmei?
- 10+ years of industry experience
- Full range of transformer bushings, oil level indicators, breathers, valves, and terminals
- Strong R&D capabilities for custom solutions
- Quality-driven with a customer-first approach
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