Depth analysis of NEMA G10 epoxy fiberglass sheets

Time: 08-05 2026 Author: Xujue Electrical

Depth analysis of NEMA G10 epoxy laminate sheet. Get detailed performance specs, thermal class comparisons, and expert insights for electrical insulation design.

What is G10?

G10 epoxy fiberglass sheet(NEMA Grade G10) is a glass fiber fabric reinforced epoxy resin laminated sheet. Under the international IEC standard, its equivalent material is generally EPGC201. It is manufactured by impregnating electrical-grade E-glass fiberglass cloth with epoxy resin and curing it under high temperature and high pressure. Today, it is one of the most widely used electrical insulation structural materials in industrial applications.

G10 fiberglass sheet

I. G10 Material Composition

G10 mainly consists of two components:

Material	Proportion	Function
E-Glass Fiberglass Cloth	55–70%	Provides mechanical strength
Epoxy Resin	30–45%	Provides electrical insulation and chemical resistance

The complete manufacturing process includes:

Fiberglass Cloth → Resin Impregnation → B-stage Prepreg → Multi-layer Lamination → Hot Press Curing → Post Curing → CNC Machining

Because the glass fibers are continuously aligned throughout the laminate, G10 is considered a true structural composite material.

II. International Standards

G10 is mainly manufactured and tested according to the following standards:

Standard	Description
NEMA LI-1	U.S. standard for laminated thermoset materials
IEC 60893	International standard for electrical insulating laminated sheets
ASTM D709	Electrical insulation testing standard
UL94	Flammability rating (Standard G10 is typically HB)
RoHS / REACH	Environmental compliance requirements

III. Typical Properties

Performance data may vary slightly among manufacturers. The specifications listed above are based on Xujue Electrical’s G10 products and are provided for reference only.

G10 Epoxy Fiberglass Sheet Parameter：

Product name	NEMA GRADE G10/EPGC 201
SECTIONI-MISC CHARACTERISTICS
Density	g/cm³		1.95-2.10
Flammability			HB
Water absorption (5mm)	%		s0.15
Chemical family	Resin		Epoxy
Reinforcement type	Glass fabrics		7628
Thermal characteristics	°C		130±5
Colour	Green (Natural),Yellow
SECTION II-MECHANICAL CHARACTERISTICS
Bending strength	MPa		≥400
Tensile strength	MPa		≥300
Compressive strength ⊥	MPa		≥350
Modulus of elasticity	MPa		≥24000
Impact strength//	kJ/m²		≥33
SECTION-ELECTRICAL CHARACTERISTICS
Electrical strength ⊥	KV/mm,thickness≤3mm		≥10.2
Breakdown voltage//	kV		≥35
Proof tracking index	PTI		≥200
SECTION IV-HAZARDOUS INGREDIENTS
Hazardous components	No OSHA hazardous ingredients
SECTIONV-REACTIVITY DATA
Chemical stability	Stable under normal conditions
Conditions to avoid	Avoid longtime heating above 125°C
Incompatible materials	Exposure to strong acids or bases will cause damage
Hazardous polymerizations	Will not occur
Storage and use effects	Conventional performance remains stable within 1 year.Long-term exposure to sunlight and high humidity will cause discoloration and performance degradation.
SECTION VI-PRECAUSTION
Over exposure effects	Dust from machining products can iritate the eyes,nose,throat and lungs.Prolonged inhalation of dust can cause lung disease.
Note:Aliformation,recommendations and suggestions appearing herein concerning this product are average values ascertained at room temperature by regular statistical analysis.It is provided purely for information and shall not be regarded as binding unless expressly agreed otherwise.
DIMENSIONAL TOLERANCE	Tolerance of length &width is less than 5mm
Thickness(mm)	Tolerance(mm)	Thickness(mm)	Tolerance(mm)
0.5-0.8	±0.05	6.0-8.0	±0.50
1.0-1.8	±0.15	10.0-15.0	±0.75
2.0-2.8	±0.20	16.0-20.0	±1.00
3.0-5.0	±0.30	21.0-50.0	±2.00

The greatest advantages of G10 are:

High mechanical strength • High dielectric strength • Excellent dimensional stability • Outstanding machinability • Good insulation performance under humid conditions

Why Is G10 So Durable?

There are three main reasons:

First: Glass fibers themselves do not easily age.

Second: Epoxy resin has a highly cross-linked molecular structure.

Third: The laminated structure prevents cracks from propagating rapidly.

Therefore, the typical service life of G10 can reach 10–30 years or even longer.

What Are the Limitations of G10?

Not flame retardant: Standard G10 is rated UL94 HB.

Therefore, the electronics industry generally prefers FR4 instead of G10.

Limited long-term heat resistance: Standard G10 is suitable for continuous operation at approximately 130°C, but it is not designed for long-term service at 200°C.

For higher temperature applications, it is recommended to use:

G11 or Polyimide Laminated Sheets (PIGC Series).

Selection Guide: Thermal Class Comparison

Besides flame retardancy, another key selection factor is the thermal class. In practical purchasing and engineering applications, G10 is often compared with equivalent materials under different international standards.

Grade	Thermal Class	Continuous Operating Temperature	Key Features & Typical Applications
G10 (NEMA Standard)	Class B	130°C	Standard grade with excellent overall performance and cost-effectiveness. Suitable for general motors and electrical insulation components.
FR4 (NEMA Standard)	Class B	130°C	Flame-retardant version of G10 (UL94 V-0). Recommended whenever flame resistance is required.
G11 (NEMA Standard)	Class F	155°C	Better heat resistance and higher mechanical strength retention at elevated temperatures. Suitable for higher-temperature electrical equipment.
EPGC203 (IEC Standard)	Class F	155°C	IEC equivalent of G11. Widely used in Class F motors and electrical equipment.
EPGC308 (IEC Standard)	Class H	180°C	Superior high-temperature performance. Designed for Class H motors and electrical equipment operating under demanding thermal conditions.

Purchasing Recommendations

For international procurement, it is recommended to confirm the following specifications:

Parameter	Recommended Confirmation
Material Grade	G10 / EPGC201
Dimensions	Length × Width × Thickness
Thickness Tolerance	e.g. ±0.05 mm, ±0.10 mm
Color	Green, Yellow, Black, Natural
Flame Retardancy	Whether FR4 is required instead of G10
Thermal Class	Class B (130°C) or Class F (155°C)
Testing Standards	NEMA, IEC, ASTM
Machining Requirements	CNC machining, drilling, engraving, chamfering, etc.
Certifications	UL, RoHS, REACH (if required by the project)

Consult the manufacturer

If you are looking for G10/G11/FR4 epoxy fiberglass sheets, please contact Xujue Electrical.
Xujue Electrical is a professional manufacturer of high-quality electrical insulation materials with more than 65 years of manufacturing experience.it can be customized according to the product specifications, thickness and purpose you need.
Contact us now to get detailed product information and quotation. We can also mail samples for free for your testing.

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