When it comes to high-voltage insulation in the power industry, G11 epoxy fiberglass sheet is the material of choice for engineers who need reliable performance under demanding thermal and mechanical conditions. This guide covers what G11 is, where it's used, and how to source the right custom insulation board for your project.
G11 is a rigid laminate made from woven fiberglass cloth bonded with epoxy resin, cured under heat and pressure. Classified as IEC 60893 EPGC 203, it delivers outstanding dielectric strength, excellent mechanical rigidity, and continuous operating temperatures up to 155°C (Class F) — making it a clear upgrade over FR4 or G10 for structural power applications.
Quick spec snapshot: Tensile strength ≥350 MPa · Bending strength ≥450 MPa · Water absorption ≤0.12% · Thickness range: 0.5 mm – 50 mm.
| Property | G11 | FR4 | G10 |
|---|---|---|---|
| Max. Operating Temp. | 155°C | 130°C | 130°C |
| Mechanical Strength | Excellent | Good | Good |
| UL94 V-0 Flame Rating | ✗ | ✓ | ✗ |
| Best Use Case | Power equipment | PCBs | General insulation |
• High-voltage switchgear — insulating barriers, bus bar supports, arc chutes
• Power transformers — winding formers, coil end supports, interlayer insulation
• Solar & wind inverters — mounting plates, phase separators
• EV battery systems — cell spacer plates, BMS carrier boards
• Rail traction equipment — power distribution panels, insulator brackets /p>
As a specialist G11 epoxy fiberglass sheet manufacturer, we support the full range of custom requirements：
• Precision cut-to-size: ±0.2 mm tolerance on length and width
• CNC routing, drilling, and milling for complex profiles
• Thickness grinding to ±0.05 mm for sealing-surface applications
• IEC 60893 material certificates and RoHS compliance documentation
What is the difference between G11 and FR4 epoxy sheet?
G11 handles continuous temperatures up to 155°C with superior mechanical strength, making it ideal for structural insulation in power equipment. FR4 adds UL94 V-0 flame retardancy at a lower 130°C thermal class — the go-to choice for PCBs, not structural insulation.
Can G11 sheets be custom cut and machined?
Yes. G11 can be precision cut, CNC routed, drilled, and ground to custom dimensions. Carbide tooling is recommended for best results on the glass-fiber reinforcement.
What IEC standard does G11 comply with?
G11 epoxy fiberglass sheet is classified under IEC 60893 as Type EPGC 203, the benchmark for mechanically and thermally stable epoxy-glass laminates used in electrical engineering.
