Overview
EP-GC-308 belongs to the family of glass-fabric laminates: layers of glass fabric are impregnated with an epoxy resin specially formulated for higher continuous temperatures and pressed under heat and pressure into sheets, rods or tubes. The colour is characteristically brown. A reliable assignment to a DIN 7735 Hgw short designation is not established for this grade; EP-GC-308 is therefore listed here exclusively under its EN 60893 designation.
Within the epoxy/glass-fabric series, EP-GC-308 is rated for continuous-use temperatures well above the standard grade (around 130 °C) and also above the 155 °C class: the temperature index acc. to IEC 60216-1 is 180, achieved through an adapted resin formulation that at the same time enables higher mechanical strength values – typical values are a flexural strength around 630 MPa, a tensile strength around 370 MPa and a modulus of elasticity around 31,000 MPa.
Electrically, the material offers a comparative tracking index of CTI 200-250 and an electric strength of 90 kV (∥) resp. 70 kV (⊥). Typical applications include apparatus engineering, electrical engineering and switchgear construction in the medium-voltage range, and transformer manufacturing – wherever high-strength insulating parts are required at elevated operating temperature in the immediate vicinity of heat sources. EP-GC-308 is not declared for direct food contact.
Technical Data
| Property | Value | Test Standard |
|---|---|---|
| Mechanical Properties | ||
| Flexural strength | 630 (DIN 7735: 350) MPa | DIN 53452 |
| Flexural strength at elevated temperature | 458 (DIN 7735: 175) MPa | DIN 53452 |
| Tensile strength | 370 (DIN 7735: 220) MPa | DIN 53455 |
| Compressive strength | 330 (DIN 7735: 150) MPa | DIN 53454 |
| Impact strength | 219 (DIN 7735: 100) kJ/m² | DIN 53453 |
| Notched impact strength | 65 (DIN 7735: 50) kJ/m² | DIN 53453 |
| Bond strength (splitting force) | 4100 (DIN 7735: 3000) N | DIN 53463 |
| Modulus of elasticity | 31 · 10³ (DIN 7735: 18 · 10³) MPa | DIN 53452 |
| Electrical Properties | ||
| Surface resistivity | 10¹² (DIN 7735: 5 · 10¹⁰) Ω | DIN 53482 |
| Electric strength ∥ / ⊥ | 90 / 70 (DIN 7735: 40 / 40) kV | DIN 53481 |
| Dielectric dissipation factor (1 MHz) | 0.03 (DIN 7735: 0.05) | DIN 53483 |
| Dielectric constant | 4 (DIN 7735: 5) | DIN 53483 |
| Comparative tracking index CTI | 250 (DIN 7735: 200) | IEC 60112 |
| Electrolytic corrosion (tracking) | AN 1.2 (DIN 7735: AN 1.4) | DIN 53489 |
| Thermal Properties | ||
| Temperature limit / TI | 155/180 °C | VDE 0304 / IEC 60216 |
| Thermal conductivity ∥ / ⊥ | 0.3 / 0.25 W/(m·K) | DIN 52612 |
| Coefficient of linear expansion ∥ / ⊥ | 10-20 / 15 · 10⁻⁶/K | VDE 0304 |
| Thermal class | F / H | VDE 0534 |
| General Properties | ||
| Density | 1.7-1.9 (typical 1.86) g/cm³ | DIN 53479 |
| Water absorption (5 mm thickness) | 14 (DIN 7735: 30) mg | DIN 53495 |
| Glow resistance | 2a | DIN 53459 |
| Colour | brown | – |
Frequently Asked Questions about EP-GC-308
1What is EP-GC-308?+
EP-GC-308 (acc. to EN 60893) is the high-temperature special grade of the epoxy/glass-fabric laminate series for apparatus, electrical and transformer engineering at an elevated continuous-use temperature. The temperature index acc. to IEC 60216-1 is 180, achieved through an adapted resin formulation that at the same time enables higher mechanical strength values. The colour is characteristically brown.
2How does Liedtke machine EP-GC-308?+
We machine precision parts from EP-GC-308 sheets, round bars and tubes. Sawing, milling, drilling and turning produce clean, dimensionally accurate results with sharp, carbide-tipped or diamond-coated tools, and we allow for the increased tool wear caused by the glass fabric while ensuring adequate dust extraction.
3What determines the price of an EP-GC-308 part?+
The component price is determined mainly by sheet thickness, dimensions, material utilisation, machining effort and batch size. Due to the special high-temperature resin formulation, EP-GC-308 is priced above the standard and 155 °C grades of the series. We are glad to provide binding prices on request based on your drawing.
4When is EP-GC-308 not the right choice?+
EP-GC-308 is not declared for direct food contact. If the 130 °C or 155 °C class is thermally sufficient, EP GC 202 resp. EP GC 203 are the more economical choice. As a thermoset, EP-GC-308 also cannot be reshaped or welded, and a documented DIN 7735 Hgw assignment is not reliably established for this grade.
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