Request a Quote for High-Voltage Components&Equipment

Tell us your requirements — rated voltage, model, quantity, and destination — and our XBR Electric team will prepare a detailed quotation within 24 hours.
Contact Form Demo
Medium Voltage Insulation Components

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.

TG3 Series GIS Gas-Tight Eco-Cabinet IEC 60137 Standard
Technical Overview

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.

Standard Wall Bushings (Air) KYN28 / High Voltage
12kV XBRELE TG3 12kV Series
TG3-12kV Rectangular Series
Specs Included: 110×180, 140×200, 130×210, 172×227, 220×220
View 6 Drawings
24kV XBRELE TG3 24kV Series
TG3-24kV Enhanced Series
Specs Included: 175×255, 180×180, 190×190, 220×220
View 5 Drawings
40.5kV XBRELE TG3 40.5kV Series
TG3-40.5kV Heavy Duty
Specs Included: 260×260×395, 260×260×450, 220×220
View 3 Drawings
12kV XBRELE Square Flange
TG1/TG2 Square Flange
Specs Included: TG1-155 (125×125), TG2-182 (152×152), TG4-128
View 3 Drawings
Specialized Bushings GIS & Eco-Cabinet
GIS / SF6 XBRELE GIS Cone Bushing
GIS Cone Interface
Models Included: Bushing 202 (630A/1250A), Bushing 235
View 4 Drawings
Cable Box XBRELE Double Pass Bushing
Through / Double Pass
Models Included: Bushing 180, 198, 285, 254, 281
View 5 Drawings
Eco / Solid XBRELE Eco Elbow
Elbow / Side-Expand
Types Included: L-Shape Standard, Type 85, Type 88
View 3 Drawings
Eco / Solid XBRELE Eco Straight
Eco Outgoing / Metering
Types Included: Bushing 260, 265, 250 Metering
View 4 Drawings
Details ×
XBRELE Technical Drawing
Select a model from the list
Model IDDim / FeatureNote
Engineered for High Voltage Switchgear

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.

Molding Technology

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.
Insulation Performance

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).
Structural Integrity

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.
Quality Control

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.

QA Standards

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.
For test reports or other products like contact boxes, visit our Switchgear Parts pillar page.
Supply Chain & Support

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.

Fast Replacement

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.
OEM Customization

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.
Export Packaging

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.
Get a Quote Now
FAQ · Technical Support

Common Questions About Wall Bushings

Technical answers regarding voltage ratings, material properties, installation environments, and compatibility with KYN28 switchgear.

Do you manufacture 15kV wall bushings?
Yes. In IEC standards, the rated voltage is 12kV, which corresponds to the 15kV class in IEEE/ANSI standards. Our 12kV epoxy bushings are fully rated for systems up to 12kV (BIL 75kV) and are widely used in 10kV, 11kV, and 15kV switchgear applications.
What is a through-wall bushing used for?
A through-wall bushing provides electrical isolation and mechanical support for high-voltage conductors passing through grounded metal partitions (such as between the busbar compartment and circuit breaker room). XBRELE bushings are standard for indoor KYN28/UniGear panels.
Why choose Epoxy Resin (APG) over Porcelain?
Epoxy resin bushings made via APG technology offer significant advantages over porcelain: they are lighter, have higher mechanical tensile strength, tighter dimensional tolerances for assembly, and are free from internal air voids (lower Partial Discharge).
What is the operating environment?
Standard bushings are designed for indoor use with ambient temperatures from -10°C to +40°C and altitudes up to 1000m. For high-altitude areas (>1000m), we offer specialized extended-creepage models (e.g., ZJ-40.5kV High Altitude series).
When should I use a shielded wall bushing?
Shielded bushings (with an internal capacitive screen) are recommended for higher voltage ratings (24kV, 40.5kV) or high-current systems (>2500A). The shielding helps distribute the electric field evenly, preventing partial discharge around the mounting flange.
Do you provide CAD drawings?
Yes, we provide detailed drawings for all TG1, TG3, and GIS bushings. You can view dimensions directly in our product catalog section above. For compatible circuit breakers, please check our VS1 Vacuum Circuit Breaker page.
Are these bushings maintenance-free?
Yes, XBRELE epoxy bushings are virtually maintenance-free. The high-quality resin surface is resistant to dust and moisture accumulation. However, during routine switchgear maintenance, we recommend wiping the surface to prevent conductive dust buildup.
What is the lead time for bulk orders?
For standard models like TG3-12/110x180, we often have stock for immediate shipment (3-5 days). For custom OEM orders or large batches (>500 units), the typical lead time is 15-20 days. Please contact us for urgent requests.