Application of GPO-3 Insulation sheet in Circuit Breakers

With the continuous development of low- and medium-voltage power distribution systems toward higher safety, modular d...

With the continuous development of low- and medium-voltage power distribution systems toward higher safety, modular design, and improved reliability, the performance requirements for internal insulation components in circuit breakers are becoming increasingly stringent. GPO-3 insulation Sheet, known for its excellent electrical insulation properties, high mechanical strength, and outstanding flame-retardant performance, is widely used in various types of low- and medium-voltage circuit breakers and has become a key structural and insulating material.

1. What Is GPO-3 Insulation Sheet

GPO-3 insulation sheet (also known as UPGM203) is a glass-fiber-reinforced unsaturated polyester laminated sheet, manufactured in accordance with international standards such as IEC and NEMA. Its typical characteristics include:

Excellent electrical insulation performance
High mechanical strength and impact resistance
Superior flame-retardant properties (typically UL94 V-0)
Good arc resistance and tracking resistance
Easy machinability (cutting, drilling, milling)

These features make GPO-3 an ideal material for insulation and structural components in circuit breakers and other electrical switching equipment.

2. Main Applications of GPO-3 in Circuit Breakers

In circuit breaker structures, GPO-3 insulation boards are commonly used in the following key components:
Phase Barriers
Used to electrically isolate different phases, preventing phase-to-phase short circuits and enhancing the overall insulation safety level of the circuit breaker.
Insulating Supports and Mounting Plates
Serve as structural supports for conductive parts such as busbars and contact systems, providing both mechanical strength and reliable electrical insulation.
Insulating Structures Around Arc Chutes
Thanks to its good arc resistance, GPO-3 is well suited for use in areas close to arc extinguishing systems, helping reduce arc-induced damage to insulation materials.
Internal Structural Partition Panels
Used to separate functional zones within the circuit breaker, improving structural stability and operational reliability.

3. Advantages of Using GPO-3 in Circuit Breakers

Compared with traditional materials such as phenolic laminates or standard epoxy sheets, GPO-3 offers significant advantages in circuit breaker applications:
Higher flame-retardant safety: Helps suppress flame propagation under fault or short-circuit conditions
Greater mechanical reliability: Suitable for environments with frequent operations and high mechanical stress
Stable electrical performance: Maintains reliable insulation properties even under humid or demanding conditions
Excellent processing adaptability: Ideal for mass production of customized and complex structural components, reducing overall manufacturing costs

4. Typical Application Scenarios

GPO-3 insulation boards are widely used in the following types of circuit breakers and power distribution equipment:
Air Circuit Breakers (ACB)
Molded Case Circuit Breakers (MCCB)
Low-voltage switchgear assemblies
Industrial power distribution and renewable energy power systems
Especially in industrial and commercial power distribution systems with high requirements for flame retardancy and structural strength, GPO-3 has become one of the mainstream insulation material choices.

5. Conclusion

As a well-balanced and widely proven electrical insulation material, the application of GPO-3 insulation boards in circuit breakers significantly enhances equipment safety and reliability while supporting structural optimization and long-term stable operation. For circuit breaker manufacturers and power distribution system integrators, selecting high-quality GPO-3 insulation boards is an important step toward product performance upgrades and compliance with international standards.