GPO-1, GPO-2, and GPO-3: Characteristics and Applications

GPO-1, GPO-2, and GPO-3 are all glass-reinforced unsaturated polyester resin laminates. While they belong to the same material system, they exhibit significant differences in formulation, performance, and applicable standards (grades). Overall, their performance levels and applications demonstrate a gradual escalation.

The "GPO" designation, which may have originally originated as a product designation for specific manufacturers (such as PPG), has become a generic industry designation for these polyester laminates. Their performance must comply with or reference relevant standards, such as the National Electrical Manufacturers Association (NEMA) standards for NEMA GPO-1, GPO-2, and GPO-3, or China's JB/T 8149 standard.

GPO-1: Economical and Practical

As the foundational grade in the series, GPO-1 is an economical and practical product. It is reinforced with alkali-free glass fiber mat, impregnated with unsaturated polyester resin, and then cured under heat and pressure. Its comprehensive performance meets the requirements of most non-demanding environments, with stable mechanical and electrical properties.

►Main Applications

Basic insulating components in general electrical equipment, such as brackets, gaskets, and spacers.

Non-core insulating components in low-voltage switchgear and control cabinets that do not require high-strength or high-risk insulation.

Insulating components in some mechanical equipment, such as gears and pulleys, that require insulation.

Civil applications such as advertising signs and display stands primarily utilize its ease of processing.

GPO-2: Improved and Enhanced

GPO-2 is an improved and upgraded version of GPO-1. By utilizing a higher-quality resin system and more advanced molding processes, its performance is comprehensively enhanced, particularly in mechanical strength, heat resistance, and arc resistance. As a well-balanced and reliable material, GPO-2 is currently the most widely used grade.

►Main Applications

Critical insulating components in medium- and low-voltage electrical equipment, such as circuit breaker baseplates and operating mechanism partitions.

Core insulating components in motors and transformers, including slot wedges and end blocks, must withstand certain mechanical stresses and temperature environments.

Insulating supports, which require high mechanical strength and heat resistance, must stably support the equipment structure and isolate the current.

Enclosures such as distribution boxes and megohmmeter housings require both insulation protection and structural stability.

GPO-3: High-Performance Flame-Retardant

As a high-performance flame-retardant product, GPO-3's most notable feature is its inherent flame retardancy. This property is achieved by adding a large amount of inorganic flame-retardant filler (typically aluminum hydroxide) to the polyester resin. During combustion, aluminum hydroxide decomposes, absorbing heat and releasing water vapor, effectively isolating oxygen and lowering the temperature, resulting in a flame-retardant and self-extinguishing effect. GPO-3 also boasts a high Relative Temperature Index (RTI) and Comparative Tracking Index (CTI), maintaining stable insulation performance in high-temperature and highly polluted environments.

►Main Applications

Core components of high-voltage switchgear: Such as SF6 switchgear, central cabinets, partitions, valves, and insulation covers in gas-filled cabinets. This is GPO-3's core application area.

Applications with stringent fire protection requirements: Low-voltage power distribution systems in subways, ships, mines, and high-rise buildings must meet high safety standards for flame retardancy.

Components with high arc resistance requirements: Such as arc extinguishers and arc chute plates, which must withstand the direct effects of high arc temperatures.

Terminal blocks and structural components of electrical products meet insulation, flame retardancy, and structural support requirements.

The GPO series laminates, through differentiated formulations and processes, offer a product portfolio covering basic needs to high-performance requirements. GPO-1 meets general-purpose needs with affordability, GPO-2 addresses mid-range and high-end requirements with balanced performance, and GPO-3 addresses harsh environments with flame retardancy and high stability. Together, these three offer a diverse range of material options for electrical, mechanical, and other fields.