What is NEMA G-10 Standard? Properties, Applications & FR-4 vs G10

NEMA G-10 technical standard: What are the differences between G10 and FR4? Product applications and selection methods.

NEMA G-10 Standard (governed by the National Electrical Manufacturers Association NEMA LI-1 specification) is the global industrial standard established for “Epoxy Glass Fabric Laminates.”

This standard specifies a rigid composite material composed of a continuous filament woven fiberglass cloth reinforcement material impregnated with a thermosetting epoxy resin binder and cured under high temperature and pressure.

Core Technical Specifications

According to NEMA official and military specifications (MIL-I-24768/2), qualified G-10 materials must meet the following rigid physical and electrical thresholds at room temperature (23°C):

Crucial Baseline Comparison: G-10 vs. FR-4

In industrial purchasing, G-10 and FR-4 are often considered the same material. However, according to strict NEMA standard definitions:

G-10 is non-flame retardant: It contains no added halogens or flame retardants, and its room-temperature flammability rating is typically only UL 94HB.
FR-4 is the flame-retardant upgrade: It shares the same basic composition as G-10 but incorporates flame-retardant additives, requiring it to meet the UL 94V-0flammability rating.
Physical variations: When fire-retarding capabilities are not required, pure G-10 generally offers superior resistance to salt spray and high humiditycompared to FR-4, alongside slightly higher mechanical strength at elevated temperatures.

Four Major Advantages of NEMA G-10

Extreme Dimensional Stability: Boasting an exceptionally low water absorption rate, its volume remains virtually unchanged even when submerged in water or subjected to tropical, highly humid environments.
Superior Mechanical Rigidity: It ranks among the best of all industrial plastics and rigid insulating laminates regarding flexural and impact strength.
Excellent Cryogenic Performance: It does not become brittle at ultra-low temperatures; instead, its mechanical strength increases as the temperature drops.
Outstanding Chemical Resistance: It is immune to most acids, alkalis, petroleum solvents, and cleaning agents, making it highly resistant to corrosion and degradation.