NEMA & Engineering Plastic Grades Directory
This directory lists every grade page in the FedMat grades cluster, organized by parent material family. Use it to find the right NEMA designation, understand how grades differ within a family, and navigate to detailed specification pages.
Each grade page covers: chemistry, key properties, standard sizes, applicable standards (NEMA LI 1, MIL-I-24768, ASTM D709), comparison to neighbor grades, and a quote CTA.
Paper Phenolic Grades
Paper phenolic laminates are built from kraft paper saturated with phenolic resin. The NEMA grade designates whether the laminate is optimized for mechanical service, electrical insulation, or punch-press production.
| Grade | URL | Primary use | MIL spec |
|---|---|---|---|
| NEMA XX | /resources/grades/xx/ | Mechanical — gears, spacers, jigs | MIL-I-24768/11 |
| NEMA XXX | /resources/grades/xxx/ | Electrical insulation — terminal boards, panels | MIL-I-24768/13 |
| NEMA XXX-P | /resources/grades/xxxp/ | Hot-punch production — terminal boards | MIL-I-24768/15 |
| NEMA XXX-PC | /resources/grades/xxxpc/ | Cold-punch production — terminal boards, gaskets | MIL-I-24768/16 |
Parent material: Paper Phenolic
Cotton/Canvas Phenolic Grades
Canvas phenolic laminates use woven cotton canvas reinforcement instead of paper, delivering higher impact strength and toughness. Two primary NEMA grades:
| Grade | URL | Primary use | MIL spec |
|---|---|---|---|
| NEMA C | /resources/grades/c/ | Mechanical — gears, bushings, wear parts | MIL-I-24768/3 |
| NEMA CE | /resources/grades/ce/ | Electrical + mechanical — switchgear panels, motor brush holders | MIL-I-24768/4 |
Parent material: Canvas Phenolic
Linen Phenolic Grades
Linen phenolic uses fine-weave linen or linen/cotton blend fabric, producing a smoother machined surface than canvas phenolic. Two primary NEMA grades:
| Grade | URL | Primary use | MIL spec |
|---|---|---|---|
| NEMA L | /resources/grades/l/ | Fine-tolerance mechanical — instrument gears, precision bushings | MIL-I-24768/5 |
| NEMA LE | /resources/grades/le/ | Electrical + fine finish — coil forms, relay insulators | MIL-I-24768/6 |
Parent material: Linen Phenolic
Glass-Fabric Phenolic and Thermoset Grades
Glass-reinforced laminates use woven E-glass cloth as reinforcement. The resin determines the grade: phenolic (G3), melamine (G5, G9), silicone (G7), or epoxy (G10, G11, FR4, FR5). These grades span electrical insulation from 250°F to 425°F continuous service.
| Grade | URL | Resin | Key differentiator | MIL spec |
|---|---|---|---|---|
| NEMA G3 | /resources/grades/g3/ | Phenolic | Foundational glass phenolic; lowest cost | MIL-I-24768/1 |
| NEMA G5 | /resources/grades/g5/ | Melamine | Higher arc resistance than G3 | MIL-I-24768/9 |
| NEMA G7 | /resources/grades/g7/ | Silicone | 425°F continuous; Class H insulation | MIL-I-24768/17 |
| NEMA G9 | /resources/grades/g9/ | Melamine | Arc resistance >120 s (ASTM D495) | MIL-I-24768/2 |
| NEMA G11 | /resources/grades/g11/ | High-Tg Epoxy | 285°F; Tg ~170°C; non-FR | MIL-I-24768/18 |
Parent material: Glass Phenolic | Glass-Silicone | Glass-Melamine
Glass-Epoxy Grades (G10 / FR4 Family)
G10 and FR4 are the dominant glass-epoxy laminates. They share identical glass reinforcement and similar epoxy chemistry — the critical difference is flame retardancy.
| Grade | URL | Flame retardant | Tg | Key use |
|---|---|---|---|---|
| NEMA G10 | /resources/grades/g10/ | No | ~130°C | Industrial glass-epoxy; no FR requirement |
| NEMA FR4 | /resources/grades/fr4/ | Yes (V-0) | ~130–140°C | UL-listed panels, PCB substrate, FR-required |
| NEMA G11 | /resources/grades/g11/ | No | ~170°C | High-temp; G10 upgrade for 285°F service |
| NEMA FR5 | /resources/grades/fr5/ | Yes (V-0) | ~170°C | High-temp + FR; FR4 upgrade for 285°F service |
G10 ≠ FR4. FR4 has brominated flame-retardant chemistry (UL94 V-0); G10 does not. Never specify one in place of the other without checking your compliance requirement.
Material hubs: G10 | FR4 Comparison: G10 vs. FR4
Polyester Glass Mat Grades
GPO-3 is a glass-mat (not woven-cloth) reinforced polyester thermoset — the dominant arc-resistant, flame-retardant insulation laminate in North American switchgear.
| Grade | URL | Arc resistance | Flame retardant | Key use |
|---|---|---|---|---|
| GPO-3 | /resources/grades/gpo-3/ | ≥180 s | Yes (V-0) | Switchgear barriers, bus bar supports, arc chutes |
Acetal Copolymer Grades and Brands
Acetal copolymer (POM-C) stock shapes are sold under multiple brand names. These grade pages cover the two major commercial acetal copolymer brands and distinguish them from acetal homopolymer (Delrin).
| Grade/Brand | URL | Manufacturer | Notes |
|---|---|---|---|
| Celcon | /resources/grades/celcon/ | Celanese | US-primary brand; FDA grades available |
| Hostaform | /resources/grades/hostaform/ | Celanese (fmr. Ticona) | European-heritage brand; ISO-standard data; EU food contact grades |
Acetal copolymer ≠ Delrin (acetal homopolymer). Delrin is DuPont's acetal homopolymer (POM-H) — higher room-temperature stiffness. Celcon and Hostaform are POM-C copolymer — better hot-water resistance, no centerline porosity in large rod. See Delrin vs. Acetal Copolymer.
Parent material: Acetal Copolymer | Delrin (Homopolymer)
Quick-Reference Grade Selector
Use this table to find the right grade for a given requirement:
| If you need… | Grade |
|---|---|
| Lowest-cost paper phenolic mechanical stock | XX |
| Electrical insulation in a paper phenolic | XXX |
| Hot-punch terminal board production | XXX-P |
| Cold-punch terminal board production | XXX-PC |
| High-impact canvas phenolic for gears | C |
| Canvas phenolic with electrical insulation | CE |
| Fine-finish linen phenolic, mechanical | L |
| Fine-finish linen phenolic, electrical | LE |
| Glass-reinforced laminate, 250°F, lowest cost | G3 |
| Glass-reinforced, arc resistant, 250°F | G5 or G9 |
| Arc resistance >120 s (ASTM D495) | G9 |
| Glass-reinforced, 425°F continuous | G7 |
| Glass-epoxy, non-FR, 266°F | G10 |
| Glass-epoxy, flame-retardant (V-0), 266°F | FR4 |
| Glass-epoxy, non-FR, 285°F (high-Tg) | G11 |
| Glass-epoxy, flame-retardant, 285°F (high-Tg) | FR5 |
| Arc-resistant, V-0, switchgear barriers | GPO-3 |
| Acetal copolymer, US supply chain | Celcon |
| Acetal copolymer, European/ISO spec | Hostaform |
Standards at a Glance
All NEMA thermoset laminates are governed by three core standards:
- NEMA LI 1 — National Electrical Manufacturers Association's laminated insulation standard. Defines grades, property minimums, and test sequences.
- ASTM D709 — ASTM International's Standard Specification for Laminated Thermosetting Materials. Provides test methods referenced in NEMA LI 1.
- MIL-I-24768 — U.S. military laminate specification with numbered sub-specifications per grade. Required for defense procurement programs.
Supplemental standards:
- IEC 60893 — International equivalent, used in European and IEC-standard equipment
- UL 94 — flammability classification (V-0, V-1, V-2, HB) referenced for FR4, FR5, GPO-3
- ASTM D495 — arc resistance test (critical for G9, GPO-3)
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