NP504 Glass Fabric Phenolic Laminate Sheet
NP504 Glass Fabric Phenolic Laminate Sheet is a woven glass fabric composite combined with a high-temperature phenolic resin system, meeting ANSI/NEMA IM 60000-2021 Grade G-3, MIL-I-24768/18 GPG, and ASTM D709 Type G-3. The material is capable of continuous operation at 175°C and delivers a compressive strength of 76,000 psi flatwise, a UL 94 V-0 flammability rating at all tested thicknesses, and excellent creep resistance from the phenolic resin system. NFPA 130 data is available in the NP504 Additional Data Sheet — NFPA 130. Not UL Listed.
Key Properties
- Flexural Strength, Condition A LW / CW: 55,000 / 50,000 psi (379.2) / (344.7) MPa (ASTM D790)
- Compressive Strength, Condition A Flatwise: 76,000 psi (524.0) MPa (ASTM D695)
- Tensile Strength, Condition A LW / CW: 42,000 / 34,000 psi (289.6) / (234.4) MPa (ASTM D638)
- Izod Impact Strength, Condition E-48/50 LW / CW: 12.00 / 11.00 ft-lb/in (6.41) / (5.87) J/cm (ASTM D256)
- Flammability Rating, Condition A: V-0 at 0.0625″, 0.125″, and 0.500″ (UL Bulletin 94)
- Temperature Index — Electrical / Mechanical: 140 / 170°C (UL Bulletin 746b)
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- Specifications
- Applications
- General Info
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Physical Properties
| Property | Value | Test Method |
| Specific Gravity | 1.80 | ASTM D792 |
| Rockwell Hardness (0.250″ Build-up) | 110 M Scale | ASTM D785 |
| Moisture Absorption, Condition D₁-24/23 | 0.65% | ASTM D570 |
| Flexural Strength, Condition A LW / CW | 55,000 / 50,000 psi (379.2) / (344.7) MPa | ASTM D790 |
| Flexural Modulus, Condition A LW / CW | 1,800 / 1,400 kpsi (12.4) / (9.7) GPa | ASTM D790 |
| Tensile Strength, Condition A LW / CW | 42,000 / 34,000 psi (289.6) / (234.4) MPa | ASTM D638 |
| Izod Impact Strength, Condition E-48/50 LW / CW | 12.00 / 11.00 ft-lb/in (6.41) / (5.87) J/cm | ASTM D256 |
| Compressive Strength, Condition A Flatwise | 76,000 psi (524.0) MPa | ASTM D695 |
| Bonding Strength, Condition A | 1,500 lb (680.4) kg | ASTM D229 |
| Shear Strength, Condition A Perpendicular | 18,000 psi (124.1) MPa | ASTM D732 |
Thermal Properties
| Property | Value | Test Method |
| Temperature Index — Electrical / Mechanical | 140 / 170°C | UL Bulletin 746b |
| Coefficient of Thermal Expansion, X-axis / Y-axis | 15.0 / 18.0 (“/”/°C × 10⁻⁶) | IPC-TM 650-2.4.24 |
| Flammability Rating, Condition A | V-0 (at 0.0625″, 0.125″, and 0.500″) | UL Bulletin 94 |
Electrical Properties
| Property | Value | Test Method |
| Breakdown Voltage, Condition A | 55 kVolts | ASTM D149 |
| Breakdown Voltage, Condition D-48/50 | 40 kVolts | ASTM D149 |
| Electric Strength, Condition A | 600 Volts/mil (236.2) kV/cm | ASTM D149 |
| Electric Strength, Condition D-48/50 | 580 Volts/mil (228.3) kV/cm | ASTM D149 |
| Arc Resistance, Condition A | 100 sec | ASTM D495 |
| Comparative Tracking Index | 150 V | ASTM D3638 |
Compliance
- ANSI/NEMA IM 60000-2021 Grade G-3 — Compliant
- MIL-I-24768/18 GPG — Compliant
- ASTM D709 Type G-3 — Compliant
- NFPA 130 — Data available; reference NP504 Additional Data Sheet — NFPA 130
- Elevated-temperature structural insulation components rated for continuous 175°C service
- High-load compressive insulation requiring creep resistance and dimensional stability
- Switchgear and transformer insulation requiring V-0 flame rating at all thicknesses
- NFPA 130 transit system electrical insulation applications
- Military electrical insulation applications requiring MIL-I-24768/18 GPG compliance
Common industries: Electrical Equipment Manufacturing, Defense, Mass Transit, Power Distribution, Industrial Manufacturing.
NP504 Glass Fabric Phenolic Laminate Sheet is a woven glass fabric composite impregnated with a high-temperature phenolic resin system — distinct from the glass epoxy laminate family in both resin chemistry and performance profile.
The phenolic resin system provides excellent creep resistance, meaning the material resists permanent deformation under sustained compressive load at elevated temperature, and enables continuous operation at 175°C — a capability not available from standard glass epoxy grades.
With a compressive strength of 76,000 psi flatwise and a mechanical temperature index of 170°C, NP504 is engineered for high-load structural insulation applications where both thermal performance and dimensional stability under sustained compressive stress are critical design requirements.
The UL 94 V-0 flammability rating is confirmed at all three tested thicknesses (0.0625″, 0.125″, and 0.500″) — the only thermoset composite laminate in the Norplex-Micarta line to achieve V-0 across the full thickness range on this TDS. Flexural strength reaches 55,000 / 50,000 psi (LW/CW), Izod impact strength is 12.00 / 11.00 ft-lb/in (LW/CW) at Condition E-48/50, and breakdown voltage is 55 kV (Condition A) with an electric strength of 600 Volts/mil.
Arc resistance is 100 seconds and the comparative tracking index is 150 V. Moisture absorption is 0.65%. NP504 is not UL Listed.
Compliant with ANSI/NEMA IM 60000-2021 Grade G-3, MIL-I-24768/18 GPG, and ASTM D709 Type G-3. NFPA 130 data available — reference NP504 Additional Data Sheet — NFPA 130.
What differentiates NP504 Glass Fabric Phenolic Laminate Sheet from glass epoxy laminates such as NP510A (FR-4) and NP511 (G-11)?
NP504 uses a high-temperature phenolic resin system rather than an epoxy resin, which provides distinctly different performance characteristics: continuous operation at 175°C, a mechanical temperature index of 170°C (vs. 140°C for NP511 and 130°C for NP510A), V-0 flammability at all tested thicknesses, and excellent creep resistance under sustained compressive load. The compressive strength of 76,000 psi flatwise substantially exceeds any glass epoxy laminate in this line. NP504 is the appropriate choice when elevated-temperature structural integrity, creep resistance, and V-0 flame performance are simultaneously required.
Why does creep resistance matter when selecting a thermoset composite laminate for structural insulation?
Creep is the tendency of a material to deform slowly and permanently under sustained load at elevated temperature — even when stresses are well below the short-term yield strength. In high-voltage electrical equipment, insulation components are often subject to sustained bolt-load clamping, busbar clamping forces, or thermal cycling over decades of service. A material that creeps under these conditions will gradually lose dimensional accuracy, loosening joints, degrading contact pressures, and potentially compromising the electrical clearance distances designed into the assembly. NP504's phenolic resin system provides excellent creep resistance, maintaining dimensional stability under the long-term compressive loading typical of switchgear and transformer insulation service.
What is the continuous operating temperature and temperature index for NP504 Glass Fabric Phenolic Laminate Sheet?
NP504 is capable of continuous operation at 175°C per the manufacturer's TDS. The temperature index is 140°C electrical / 170°C mechanical, as listed on the Technical Datasheet.
Does NP504 Glass Fabric Phenolic Laminate Sheet meet NFPA 130 requirements?
NFPA 130 data for NP504 is available in a separate document — the NP504 Additional Data Sheet — NFPA 130, referenced on the manufacturer's TDS. The NFPA 130 data is not contained in the standard TDS. Contact H-O Products for the NP504 NFPA 130 Additional Data Sheet.
How should NP504 Glass Fabric Phenolic Laminate Sheet be specified?
Specify grade (NP504 Glass Fabric Phenolic Laminate Sheet), thickness, compliance requirements (NEMA Grade G-3, MIL-I-24768/18 GPG, ASTM D709 Type G-3, or NFPA 130 as applicable), dimensional tolerances, and finished format.
