GPO-3 Profiles: Why Are They the Core Material for Structural Electrical Insulation?

The GPO-3 profile (also known as UPGM203 profile) is a custom-shaped insulating structural component fabricated using NEMA GPO-3 grade alkali-free glass fiber mat and unsaturated polyester resin through pultrusion and molding processes. It is specifically designed for applications such as internal structural support, spacer, and busbar mounting within electrical equipment.

Main performance characteristics

As a thermosetting insulating material, GPO-3 profiles exhibit stable performance after curing and cannot be remelted. From the base materials to molding processes, they fully comply with the high requirements required for electrical equipment. Their main performance characteristics include:

• Electrical properties: Good arc resistance> 180s, CTI ≥ 600V, high dielectric strength.
• Heat resistance: Class F (continuous exposure at 155°C, short-term exposure at 210°C).
• Mechanical properties: High flexural/compressive strength, excellent rigidity, and impact resistance.
• Flame retardancy: UL94 V-0 self-extinguishing, low-smoke, halogen-free.
• Chemical properties: Oil-resistant, resistant to weak acids and weak alkalis, with low water absorption rate (~0.2%).

Common shapes of GPO3 profiles

With over a decade of professional manufacturing experience, RDS Composites has built up a comprehensive range of GPO3 profile pultrusion and molding formulas covering a wide variety of specifications. We offer profiles in a broad range of sizes and also customize molds to specific dimensional requirements. The common shapes of GPO3 profiles include:

Angular profile (L-shaped): busbar support, phase spacer plate.

Square rod / Round rod: Insulation column, spacer support strip.

Square tube / Round tube: structural beams, ventilation rods.

U-shaped channel, H/I beam, T-shaped strip, Z-shaped, and J-shaped cover.

Customized shapes: Circuit breaker arc-shielding plates, safety baffles.

GPO-3 Profile Solutions benefit All Electrical Fields

Thanks to its comprehensive performance capabilities, the GPO-3 profile has been widely adopted in core sectors with extremely high requirements for insulation, safety and reliability. It has become the standard insulation component for various types of high-end electrical equipment.

• High and low-voltage power distribution: Busbar supports, spacers and insulating brackets for switchgear, ring main units and substations, resolving challenges related to high-voltage inter-phase insulation and isolation in confined spaces, thereby ensuring the safe operation of power distribution equipment;
• Power transmission and transformation equipment: Core insulating struts, winding spacers and cooling fins for transformers and reactors, withstanding high temperatures and electromagnetic shocks to extend equipment service life;
• New energy field: Insulated brackets for new energy vehicle battery packs, insulated structural components for photovoltaic/wind power inverters, and insulated parts for energy storage equipment, meeting the new energy industry standards for lightweight design, high safety and high-temperature resistance;
• Rail transport field: Insulated spacers and structural supports for traction converters and switchgear in high-speed rail and subway systems, withstanding complex outdoor environments and long-term vibration to ensure the stability of core rail transport equipment;
• Specialised motors field: Slot wedges, armature insulation and carbon brush holder supports for high-voltage and explosion-proof motors, combining insulation properties with mechanical strength to suit high-speed motor operating conditions.