Melamine Fiberglass Laminate Tube (G9)
GF-G9
Product Overview
Melamine Fiberglass Laminate Tube (G9)
Heavy power and medium/high-voltage distribution can't afford insulation that fades in humid or wet conditions. The GF-G9 tube is built from a melamine resin system consolidated with an E-glass (electrical-grade) cloth matrix, fully cured under high heat and pressure — holding its dielectric integrity even in humid or oil-immersed service.
It delivers 3.3 kV/mm perpendicular dielectric strength (90°C, #25 oil), UL94 V-0 flammability, a CTI of 600 and 181 s arc resistance, with high mechanical strength (337 MPa flexural / 280 MPa axial compression) — suited to transformer insulation, switchgear, busbar supports and MV/HV distribution insulating parts.
Key Features
- Dielectric strength 3.3 kV/mm: perpendicular, tested at 90°C in #25 oil — dependable for heavy-power insulation
- UL94 V-0: higher flame rating than typical G9 (often only HB), for equipment fire safety
- CTI ≥600: top comparative tracking index class — resists surface tracking
- High mechanical strength: 337 MPa flexural / 280 MPa axial compression, carries structural load
- Moisture-resistant, -40 to 140°C: stable in humid / oil service across a wide range
| Specification | Value (Spec / Typical) |
|---|---|
| Material | Melamine resin + E-glass cloth (laminated) |
| Density | 1.7–1.9 / 1.94 g/cm³ |
| Water Absorption | ≤5.0 / 2.41 mg/cm² |
| Axial Compressive Strength | ≥200 / 280 MPa |
| Flexural Strength (perpendicular) | ≥200 / 337 MPa |
| Electric Strength (perpendicular, 90°C #25 oil) | ≥3.0 / 3.3 kV/mm |
| Insulation Resistance (after immersion) | 1–100 / 20 MΩ |
| Arc Resistance | ≥180 / 181 s |
| Flammability (UL94) | V-0 / V-0 |
| Comparative Tracking Index (CTI) | ≥600 / 600 |
| Coeff. of Thermal Expansion (radial / axial) | 3.5 / 4.8 ×10⁻⁶/°C |
| Operating Temperature | -40 to 140°C |
Engineering Drawing
Applications
Transformers & Switchgear
Internal transformer insulation and switchgear supports — stable dielectric performance in humid and oil-immersed heavy-power service.
MV / HV Distribution
Busbar supports, insulating bushings and switchboard parts — UL94 V-0 plus CTI 600 raise the safety margin of the distribution system.
Structural Insulating Parts
High mechanical strength allows machining into bushings, spacers and insulating supports that carry load while insulating.
FAQ
Q1｜How does G9 differ from G10/FR4 and G11? When choose G9?
G9 is a melamine-resin / glass-cloth laminate, distinguished by arc resistance, surface-tracking resistance (high CTI) and moisture-resistant insulation — a fit for heavy power and MV/HV distribution. G10/FR4 and G11 are epoxy-based with strong mechanical and general electrical properties, but usually lower arc and tracking resistance than G9. If your job values arc resistance, tracking resistance and insulation in humid environments, G9 is the matching grade.
Q2｜Why does it keep insulating in humid or oil-immersed service?
GF-G9 uses a continuous E-glass cloth base impregnated with melamine resin and cured under high heat and pressure, giving a dense structure with low water absorption (2.41 mg/cm² typical). Electric strength is tested to 3.3 kV/mm perpendicular in 90°C #25 transformer oil, and insulation resistance stays stable after immersion — so it insulates reliably in humid and oil environments.
Q3｜What do UL94 V-0 and CTI 600 mean for equipment selection?
UL94 V-0 is a high vertical-burning flame rating (typical G9 is often only HB; GF-G9 tests to V-0), meaning it self-extinguishes and won't readily sustain flame. CTI 600 is the top comparative-tracking-index class (≥600 V), meaning the surface resists forming a conductive path under dirt and moisture. Together they add fire and anti-tracking margin to high-voltage distribution.
Q4｜Can it be machined into bushings or insulating parts to size?
Yes. The melamine glass laminate is mechanically strong and machinable, so it can be turned into bushings, spacers and insulating supports to your equipment needs. For feasible dimensions, tolerances and lead time, share a drawing or spec and our team will advise and quote.
Q5｜Which voltage classes and applications suit GF-G9?
GF-G9 targets insulating structural use in heavy power and MV/HV distribution — transformer internal insulation, switchgear, busbar supports and switchboard parts. The actual voltage class depends on wall thickness, design margin and site conditions; share your application and our team will assist with selection.
Features
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Specifications
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