FR-4 Glass Epoxy Sheets Manufacturer in India
The FR-4 Glass Epoxy is a highly durable, flame resistant laminate that is produced by laminating several layers of woven fiberglass cloth using epoxy resin under certain heat and pressure conditions. It is known as the NEMA FR4 grade worldwide and it is one of the most common laminates in terms of electrical, electronics, and industrial manufacturing because it possesses all the qualities such as electrical insulation, strength, dimensional stability, and fire resistance in it.
Harnawa Inc. is an FR-4 epoxy glass laminate sheet manufacturer in India. It provides top-notch quality FR-4 laminates sheets to OEMS, panel makers, transformers, and electrical component makers in India based out of Mumbai.
What is FR-4 Glass Epoxy?
FR-4 is a flammable variant of G-10, a popular type of glass epoxy laminate. Although G-10 is a laminate known for its excellent physical and electrical characteristics, it does not have any inherent ability to resist fires. FR-4, on the other hand, is made through the same fiberglass-epoxy composite process but uses resin formulations that make the product fire-resistant according to relevant specifications. Therefore, FR-4 is the better and more versatile product; it can be used in places where G-10 is recommended, but the opposite is not possible when fire protection is a concern.
Due to the above-mentioned reasons, FR-4 is now the material of choice in switchgear fabrication, printed circuit board (PCB) manufacture, transformer insulation, and general-purpose structural insulation parts.
Material Construction
FR-4 panels are made up of woven fiberglass cloth that is impregnated with an epoxy matrix material. It is laminated in layers and then pressed together using heat to create a composite material that offers unique mechanical and physical properties, such as strength-to-weight ratio, moisture resistance, and dimensional stability — all of which cannot be achieved with fiberglass mat or cast resin alone.
Due to the bond between the fiberglass and the resin matrix material, the resultant laminate is highly durable against fracturing, splitting, or distortion during machining or thermal cycling operations.
Working Temperature & Class F Insulation Rating
FR-4 has a rated maximum temperature of continuous operation of 170°C; therefore, FR-4 falls clearly into Class F of electrical insulation temperature classifications. Thus, because of its high temperature resistance, FR-4 can be used in equipment where both thermal and electrical stresses occur — transformers, switchgear enclosures, insulation of motors and generators, as well as control panels — without losing its dielectric and mechanical characteristics during the entire life span of the equipment.
When comparing to lower-class laminates, for example, phenolic-paper based NEMA X, XX, and XXX, it becomes evident that FR-4 is characterized not only by higher temperature limits but also by much better electrical and mechanical characteristics.
Electrical & Mechanical Properties
FR-4’s popularity across the electrical industry comes down to a well-rounded property profile:
- Dielectric Strength – Ensures consistent insulation resistance and dielectric strength under both dry and humid conditions to avoid flashover or insulation failure.
- Rigidity – High resistance to bending and compression makes it possible to use FR-4 as an insulating material in a load-bearing capacity as well.
- Flame Resistance – Has been specially developed to self-extinguish and meet fire safety standards in closed electrical machinery such as switchboards and control panels.
- Resistance to Moisture – Minimal moisture content ensures uniform electrical behavior even in the presence of humidity or other varying industrial environments.
- Processability – It can be drilled, punched, sawn, and machine processed accurately without delamination.
- Resistance to Chemicals – Resists chemical attack by oils, solvents, and various industrial chemicals.
Color & Finish
FR-4 panels provided by Harnawa Inc. come in the traditional yellow color. This system of color classification complies with the global standards of NEMA and IEC, making it possible to identify their quality grades visually.
Thickness & Size Availability
We provide FR-4 sheets with custom thickness as per the need of the particular application you are working on, which can be anything from thin gauge sheets for use in PCB substrates to thick gauge sheets in switchgear or transformer applications.
These sheets can be provided in cut to size form, enabling panel manufacturers and OEMs to get materials that are ready to use without any wastage of machining time or material.
Typical Applications of FR-4 Glass Epoxy Sheets
FR-4 laminate sheets are specified across a wide range of industrial and electrical applications, including:
Manufacture of Switchgears & Panels
- Barrier materials for switchgear enclosures
- Support insulation for bus bars
- Backing boards for control panels
Printed Circuit Boards (PCBs) Manufacture
- Material for substrates of single and multi layer printed circuit boards
- Popularly used in consumer electronics, industrial controls and telecoms
Transformer Manufacturing
- Insulation barriers
- Insulation at terminal boards and clamping
- Support systems for dry-type and cast resin transformers
Motor and Generator Insulation Parts
- Slot wedges and end winding support systems
- Insulation of the terminal board
- Insulating spacers
Industrial Insulation Parts
- Washing machines, bushings, and spacers
- Insulation components for machine tools
- Insulating components of control panels and industrial electronics
FR-4 vs G-10 — Choosing the Right Grade
| Property |
G-10 |
FR-4 |
| Base Construction |
Woven fiberglass + epoxy |
Woven fiberglass + epoxy |
| Flame Retardancy |
Not flame retardant |
Flame retardant (self-extinguishing) |
| Mechanical Strength |
High |
High (equivalent to G-10) |
| Dielectric Performance |
Excellent, wet & dry |
Excellent, wet & dry |
| Recommended For |
General applications without fire-safety requirement |
Applications requiring fire safety compliance (switchgear, panels, PCBs) |
| Substitution |
Cannot replace FR-4 in fire-rated applications |
Can safely substitute G-10 in all applications |
For most modern electrical and electronic applications,
FR-4 is now the industry-default choice, since it delivers everything G-10 offers plus the added safety margin of flame retardancy — often at a comparable cost.
Building a Complete Electrical Insulation System
FR-4 sheets rarely work in isolation. In real-world motor, transformer, and switchgear assemblies, FR-4 is combined with other high-temperature insulation materials to build a complete, multi-layer insulation system:
- Aramid Papers — used for slot lining and Class H winding insulation in motors and generators, complementing FR-4 structural components
- Laminated Insulation Paper Composites — layered dielectric barrier materials used alongside FR-4 in transformer and motor construction
- Insulation Tapes High Temperature — used for coil binding, terminal wrapping, and securing components adjacent to FR-4 structural parts
- Fiberglass Insulation Sleeves — used for protecting leads and connections routed through or near FR-4 panels
- Fiberglass yarn — used for lacing and mechanically reinforcing windings in assemblies that also use FR-4 structural insulation
Sourcing all of these materials from a single, quality-certified supplier ensures compatibility, consistent quality standards, and simplified procurement for OEMs and panel manufacturers.
Quality & Certifications
All sheets of FR-4 glass epoxy offered by Harnawa Inc. have been produced and inspected in accordance with international standards of quality as indicated below:
- UL certified
- CE Marking certified
- ROHS compliant
- Manufactured ISO 9001:2015 certified
- REACH compliant
This guarantees that FR-4 sheets bought from us fulfill the requirements of both Indian manufacturers and OEM’s exporting internationally.
FR-4 Glass Epoxy Sheets Manufacturer in India — Why Choose Harnawa Inc.
Harnawa Inc. is an acknowledged Electrical Insulation Material Manufacturer in India which offers FR-4 glass epoxy sheets along with all kinds of electrical insulation material which can be used in power transformers, generators/motors, switchgear, electric vehicles (EVs), and other industrial electronic applications.
What sets us apart:
- NEMA FR4-grade laminated sheets with guaranteed availability
- Tailored to order sheet thicknesses and cut to measure dimensions
- Nationwide logistics service spanning cities such as Mumbai, Delhi, Pune, Ahmedabad, etc.
- Certified quality assurance system including UL, CE, RoHS, ISO 9001:2015, and REACH
- A one-stop solution supplier of FR-4 laminates as well as other insulation products
Frequently Asked Questions
1.What is the difference between FR-4 and G-10?
The difference lies in the fact that FR-4 is the flame retardant version of G-10. These two have the same properties, except that the former has the ability of self-extinction and thus is more suitable for critical applications such as switchgear and printed circuit boards.
2.What is the maximum operating temperature of FR-4 sheets?
The maximum operating temperature of FR-4 sheets is 170°C, and hence falls under the class of Class F insulation material.
3.Are FR-4 sheets available cut to size?
Yes. The FR-4 sheets offered by Harnawa Inc. come with customized thickness and cut to size.
4.In which industries are FR-4 glass epoxy laminates used?
FR-4 is primarily used in making switchgear, printed circuit boards, transformers, motors and generators.
