Wall Bushings & Through-Wall Insulators (12kV-40.5kV)
XBRELE’s Epoxy Wall Bushings (also known as Through-Wall Insulators) provide reliable electrical isolation for busbars passing through grounded partitions. Featuring TG3 (KYN28) and Gas-Tight (GIS) series, molded via APG technology for zero partial discharge.
High-Performance Epoxy Wall Bushings for Switchgear Isolation
XBRELE Wall Bushings (technically defined as Through-Wall Insulators) serve as the vital link in medium voltage distribution systems. They are designed to carry high-voltage conductors through the grounded metal partitions of switchgear cabinets, providing both electrical insulation and robust mechanical support for 12kV, 24kV, and 40.5kV busbars.
Our TG3 and GIS series are manufactured using advanced APG (Automatic Pressure Gelation) technology with premium epoxy resin. This process ensures a void-free internal structure, high bending strength, and excellent resistance to tracking. Every switchgear bushing undergoes strict quality control to guarantee a Partial Discharge (PD) level of < 5pC, ensuring long-term reliability in demanding substation environments.
Whether for air-insulated KYN28 cabinets or SF6 gas-insulated switchgear (GIS), XBRELE bushings ensure seamless compatibility. Our products comply with critical international standards, including IEC 60137 Insulated bushings for alternating voltages , meeting rigorous requirements for lightning impulse withstand voltage (BIL) and thermal stability.
To explore our full catalog of insulation components, including contact boxes and insulators, please visit our main Switchgear Parts & Accessories Directory .
Wall Bushings & Insulators
XBRELE™ Certified Epoxy Components. Select a series to view full dimensions.
| Model ID | Dim / Feature | Note |
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Core Technologies of XBRELE High Voltage Epoxy Bushings
XBRELE manufactures premium Epoxy Resin Insulators using advanced APG technology. Our Through-Wall Bushings are engineered to withstand extreme electrical stress and mechanical loads, providing reliable isolation for 12kV (15kV Class) to 40.5kV switchgear systems.
APG Epoxy Resin Casting
The density of an epoxy resin insulator defines its lifespan. We use Automatic Pressure Gelation (APG) to eliminate air voids.
- Void-Free Structure: High-pressure gelation ensures high dielectric strength for high voltage bushings used in critical substations.
- Mechanical Robustness: Withstands electro-dynamic forces in the busbar compartment during short circuits.
- Thermal Stability: Premium epoxy maintains integrity under high operating temperatures typical of MV switchgear.
Low Partial Discharge (< 5pC)
Internal defects lead to breakdown. Every XBRELE switchgear bushing undergoes rigorous PD testing to guarantee longevity.
- Strict Quality Control: 100% testing ensures PD is less than 5pC at rated voltage.
- Internal Shielding: Selected TG3 wall bushings feature capacitive screens to optimize electric fields (preventing corona discharge).
- Extended Lifespan: Prevents insulation aging in medium voltage applications (12kV-40.5kV).
X-Ray Flaw Detection
We use X-Ray technology to inspect the internal structure of every through-wall insulator, ensuring absolute safety.
- Non-Destructive Testing: Detects hidden micro-cracks inside the epoxy bushing body.
- Insert Alignment: Verifies precise positioning of conductors for easy switchgear assembly.
- IEC Compliance: Performance verified against IEC/IEEE standards for insulated bushings.
Manufacturing & Testing of Epoxy Switchgear Bushings
XBRELE combines precision mold design and rigorous 100% routine testing to ensure our through-wall insulators deliver zero-defect performance for Medium Voltage (MV) distribution.
APG Casting & Assembly Process
Our manufacturing line for epoxy resin bushings is optimized to eliminate internal voids and ensure high mechanical bending strength for KYN28/GIS integration.
- 01
Mold Preparation
Molds are pre-heated. Copper conductors for the wall bushing are positioned with high accuracy.
- 02
APG Vacuum Casting
Epoxy resin is injected under vacuum using APG technology, eliminating air bubbles for high insulation integrity.
- 03
Curing & Demolding
Controlled curing prevents micro-cracking in the insulator body. Demolded parts are inspected for finish.
- 04
X-Ray Flaw Detection
Verifying the bonding between the conductor and epoxy matrix to ensure no hidden defects in the bushing.
- 05
Final Testing
Routine tests for withstand voltage and dimensions are conducted before the switchgear components are packed.
Routine & Type Tests
All wall bushings are tested per IEC 60137 / GB 4109 to guarantee reliability in critical power networks.
Dielectric Performance
- Power Frequency Withstand: 42kV (12kV units), 65kV (24kV), 95kV (40.5kV).
- Partial Discharge (PD): < 5pC at 1.1x rated voltage prevents epoxy insulation aging.
- Impulse Voltage (BIL): Verified up to 75kV (15kV Class) / 125kV / 185kV.
Mechanical Properties
- Cantilever Load Test: Verifies strength to withstand busbar stress.
- Glass Transition Temp (Tg): Ensures stability under high operating temps.
- Test procedures reference IEC standards for solid electrical insulation.
Dimensional Verification
- Precision check of flange dimensions and hole centers.
- Verification of conductor terminal quality.
- Surface creepage distance measurement.
Global Delivery for Switchgear Components
XBRELE ensures rapid delivery of 12kV-40.5kV epoxy wall bushings to panel builders worldwide. We coordinate mold customization, secure packaging, and technical support for both OEM production and retrofit maintenance projects.
Stock Availability for Standard TG3
We maintain a strategic inventory of high-demand models like TG3-12/110x180 to support urgent maintenance needs for KYN28/UniGear panels.
- In-Stock Items: Ship within 3-5 days for standard 12kV bushings.
- Bulk OEM Orders: 15-20 days production lead time for large batches.
- Retrofit Kits: Square flange (TG1) and older wall insulator replacements available.
- Sample Policy: Express delivery for prototype verification.
Custom Mold Design for GIS/Eco
Beyond standard catalogs, XBRELE offers mold customization services to fit unique busbar geometries or specific GIS switchgear designs.
- Dimensional Adaptation: Custom flange size and aperture diameters.
- Special Shapes: Cone interface (Type 202/235) or shielded types for RMU.
- Insert Material: Copper or brass insert options based on conductivity.
- Private Labeling: Custom laser marking for OEM brand partners.
Secure Transport for Epoxy Resin
Epoxy resin requires careful handling to prevent surface chipping. We use reinforced packaging to ensure every through-wall bushing arrives safely.
- Individual Boxing: Each bushing is wrapped in foam and boxed separately.
- Palletization: Heavy-duty wooden pallets with shrink wrap for sea/air freight.
- Impact Protection: Corner guards and internal cushioning to absorb shock.
- Documentation: Full test reports and COC included with shipment.
Common Questions About Wall Bushings
Technical answers regarding voltage ratings, material properties, installation environments, and compatibility with KYN28 switchgear.