G11 epoxy sheet is used in and selected for power equipment.

I. G11 epoxy sheet Application Scenarios Transformers Insulating barriers: Provide electrical isolation between hig...

I. G11 epoxy sheet Application Scenarios

Transformers

Insulating barriers: Provide electrical isolation between high-voltage windings to prevent breakdown.

Support components: Withstand electromagnetic and mechanical forces to maintain structural stability.

End insulation parts: Ensure long-term insulation performance under high temperature and high voltage.

Switchgear / Circuit Breakers

Insulating partitions: Prevent short circuits and discharge between conductive parts.

Mounting supports: Withstand operational forces and arc impact during switching.

Arc barriers: Heat-resistant and flame-retardant, resistant to arc erosion.

Motors

Slot wedges: Installed in stator slots to ensure insulation between windings and core.

End supports: Maintain stability under high-speed rotation and elevated temperatures.

II. G11 epoxy sheet Selection Guidelines

Thermal Class

G11 is rated Class H (180℃), superior to FR4 (Class B, 130℃) and G10 (Class A, 120℃).

Suitable for high-temperature operation in transformers, switchgear, and motors.

Thickness Selection

Insulating barriers: typically 3.0 – 10 mm

End supports: 8 – 20 mm, depending on mechanical strength requirements

Slot wedges: 1.0 – 3.0 mm

Performance Requirements

High insulation: Dielectric strength ≥ 15–20 kV/mm

High mechanical strength: Flexural strength ≥ 350 MPa, stable even at elevated temperatures

Flame retardancy: UL94 V-0, self-extinguishing, non-flame spreading

Cost-Performance Consideration

For general electrical isolation (low-temperature, low-voltage applications), FR4 is sufficient.

For high temperature + high mechanical strength, G11 is the preferred choice.

III. Conclusion

Core Applications: G11 epoxy sheets are most widely used in transformer insulating barriers, switchgear supports, and motor slot wedges.

Selection Logic: Determine thickness and specifications based on operating temperature, dielectric strength, and mechanical load requirements.

Advantages: Compared with FR4 and G10, G11 is more suitable for high-temperature, high-voltage, and high-reliability electrical equipment.