GPO-3 is a glass-fiber reinforced polyester composite made from chopped strand mat impregnated with unsaturated polyester resin and hot-pressed into rigid sheets. It offers excellent electrical insulation, flame retardant, and mechanical strength under heat and humidity.

How does GPO-3 perform electrically?

It has high dielectric strength (10–12 kV/mm), excellent arc resistance, and stable insulation under high humidity. These properties make it suitable for medium- and high-voltage switch gear and transformer insulation.

Does GPO-3 meet Australian standards?

Yes. MISCO’ s GPO-3 conforms to international standards referenced in Australian switchboard and transformer manufacturing, including AS/NZS 61439, IEC 60893, and UL 746 requirements.

Is GPO-3 suitable for CNC drilling and tapping?

Yes. It can be drilled and tapped using carbide-tipped or PCD tools with moderate feed rates and coolant air flow to prevent heat build-up. MISCO’ s CNC facility provides precise, burr-free holes and profiles to specification.

Is GPO-3 the same as epoxy glass (G10, FR4, G11)?

No. GPO-3 uses a polyester resin system, whereas G10, FR4, and G11 are epoxy glass laminates. GPO-3 is selected for arc resistance, flame retardant, and structural insulation, while epoxy glass grades are typically used for higher mechanical or thermal classes.

What is GPO-3 typically used for?

GPO-3 is commonly used for busbar supports, cleats, phase barriers, arc shields, transformer insulation components, and switchboard structural panels in low- and medium-voltage assemblies.

Is GPO-3 flame retardant?

Yes. GPO-3 meets UL 94 V-0 flame-retardant classification, meaning it is self-extinguishing and suitable for enclosed electrical installations.

What temperature rating does GPO-3 have?

GPO-3 is rated to Thermal Class F (155 °C) in accordance with IEC 60085, making it suitable for continuous operation in elevated-temperature electrical environments.

Is GPO-3 suitable for humid or enclosed environments?

Yes. GPO-3 offers low moisture absorption, excellent dimensional stability, and maintains electrical performance in high-humidity or enclosed switchboard conditions.

Is GPO-3 halogen-free and asbestos-free?

Yes. GPO-3 is halogen-free, asbestos-free, and produces low smoke and low toxicity when exposed to fire.

Can threaded inserts or fasteners be used with GPO-3?

Yes. GPO-3 can be drilled, tapped, or fitted with threaded inserts, provided correct hole sizing, torque limits, and installation practices are followed.

Is GPO-3 suitable for defence and government projects?

Yes. GPO-3 is manufactured to IEC, NEMA, and MIL specifications and can be supplied with batch traceability, Certificates of Conformance (CoC), and Defence Certificates (DCoC) where required.

GPO-3

GPO-3 is a glass fiber reinforced, unsaturated polyester composite designed for electrical insulation, mechanical stability, and flame-retardant performance in demanding industrial environments.

Manufactured using continuous glass mat impregnated with a filled polyester resin system, the material is hot-pressed into rigid, dimensionally stable sheets that deliver reliable performance under electrical, thermal, and mechanical stress.

The composite structure provides a high dielectric withstand, excellent comparative tracking index (CTI), and strong arc-quenching characteristics, making it suitable for use in switch gear and power distribution assemblies where insulation integrity is critical.

Its mechanical strength—particularly flexural and compressive performance—allows GPO-3 components to function as both insulating and load-bearing structural parts, replacing denser or metallic alternatives while maintaining electrical clearance requirements.

SPECIFICATIONS

Product Form

Sheets, rods, tubes, machined components, and custom profiles

Standard Colours

MISCO Red / Natural White

Sheet Sizes

2100 X 1230 mm (others available)

Thickness Range

0.8 mm to 60 mm – Larger thickness are to order

Compliance

IEC 60893-3-5 EPGC203
NEMA LI-1 GPO-3
MIL-I-24768/17 Type GPO-3
UL 94 V-0 Flame Retardant
UL File No. E23525
IEC 60085 Class F (155 °C)
AS/NZS 61439 Switchboard Assembly Alignment
RoHS 3 (EU Directive 2015/863)
REACH (EC 1907/2006)
Halogen-Free / Asbestos-Free
Low Smoke / Low Toxic Fume Emission
Environmentally Responsible Manufacture
Batch Traceability Maintained
Certificate of Conformance (CoC) Available
Defence Certificate of Conformance (DCoC) Available
Manufactured under ISO 9001:2015 Quality Management Principles
Accepted for Use in Defence, Power Generation, Transport & Renewable Energy Infrastructure

MECHANICAL PROPERTIES

ELECTRICAL PROPERTIES

THERMAL PROPERTIES

High dielectric strength and insulation resistance
Provides reliable electrical separation and withstand performance in low-, medium, and high-voltage assemblies.
UL 94 V-0 flame-retardant and self-extinguishing
Engineered for controlled flame spread, minimal smoke release, and safe use in enclosed electrical equipment.
Excellent arc and tracking resistance
High CTI values and strong arc-quenching behavior ensure stability under fault, contamination, and switching conditions.
Strong mechanical and impact strength
High flexural, tensile, and compressive performance supports load-bearing and structural insulating applications.
Stable under heat, load, and humidity
Rated to Class F (155°C) with dependable mechanical and electrical retention in thermally stressed environments.
Low moisture absorption and dimensional stability
Maintains insulation and mechanical integrity in humid, coastal, and industrial atmospheres.
Halogen-free and asbestos-free composition
Safe, modern resin system free from restricted or legacy hazardous materials.
Low-smoke, low-toxicity emission characteristics
Suitable for enclosed switch gear, substations, rail rolling stock, and industrial cabinets where air quality matters.
Lightweight yet rigid structural performance
Provides stiff, stable components at a fraction of the weight of metallic alternatives.
Easy to machine, drill, and fabricate on CNC equipment
Clean edge performance with carbide or diamond tooling, enabling precise, repeatable components.
Suitable for switchboard, transformer, and power-system insulation
Widely used for barriers, supports, busbar mounts, arc-chutes, terminal boards, and control-panel parts.
Environmentally responsible and RoHS / REACH compliant
Free from heavy metals and restricted substances, supporting modern compliance and sustainability requirements.
Consistent batch-controlled quality and traceability
Manufactured using controlled resin systems, press cycles, and density tolerances for repeatable performance.
Manufactured to international and Australian standards
Typically conforms to IEC 60893 UPGM-203, NEMA GPO-3, and related AS/NZS electrical material requirements.

Switchboard and Electrical Distribution Boards
Insulating barriers, busbar supports, phase separators, mounting panels, cable-support brackets, arc-chutes, and internal structural components.
Busbar Systems and Power Distribution Assemblies
Busbar support blocks, standoff insulators, encapsulation plates, and high-strength dielectric spacers.
Transformers, Reactors, and Power Equipment
Coil supports, insulation plates, terminal panels, end-frames, clamping components, and load-bearing insulating structures.
Motor, Generator, and Rewind Applications
Structural insulation parts, slot wedges, phase insulation plates, and thermal-resistant mechanical supports.
Rail, Rolling Stock, and Tunnel Infrastructure
Electrical insulation boards, control-panel components, HV /LV isolation parts, and flame-retardant structural insulating elements.
Defence, Aerospace, and Military Systems
High-strength electrical insulating parts for power control, onboard distribution, shielding barriers, and vibration-resistant components.
Renewable Energy and Battery Storage Systems
Inverter enclosures, isolation plates, energy-storage barriers, dielectric partitions, and flame-retardant support structures.
Power Generation and Substation Equipment
HV/LV isolation panels, relay cabinet parts, switch gear partitions, and arc-resistant mechanical insulation.
Industrial Machinery and Heavy Equipment
Mechanical spacers, insulating guides, precision-machined supports, and fixtures operating under heat and load.
HVAC, Furnaces, and Thermal Processing Units
Heat-resistant supports, covers, and structural parts that require electrical insulation under elevated temperatures.
Automotive, EV, and Heavy Vehicle Electrical Systems
Battery insulation panels, control-system boards, dielectric mounting plates, and fire-retardant enclosures.
Oil, Gas, Mining, and Petrochemical Facilities
Corrosion-resistant insulating plates, structural brackets, and non-conductive mechanical components.
Data Centres and Critical Infrastructure
Isolation panels, control-cabinet components, UPS insulation plates, and fire-resistant dielectric separators.
General Engineering and CNC Machined Components
Precision-machined insulating pieces, custom brackets, jigs, fixtures, and complex geometries requiring electrical, mechanical, and thermal performance.

Switchboard Builders & Electrical Distribution Manufacturers
LV/MV switchboards, MCCs, distribution boards, control panels, and power-management assemblies.
Transformer, Motor & Generator Manufacturers / Rewinders
Power and distribution transformers, dry-type transformer systems, motor rewind shops, and rotating equipment OEMs.
Power Generation & Substation Infrastructure
Coal, gas, hydro, solar, wind, and battery storage facilities; HV/LV substation equipment and relay/control cabinets.
Renewable Energy & Energy Storage Systems
Inverters, battery isolation barriers, BESS enclosures, and dielectric support structures for solar and wind systems.
Rail, Rolling Stock & Tunnel Infrastructure
Electrical panels, insulation components, flame-retardant boards, and vibration-resistant assemblies.
Defence, Aerospace & Military Systems
High-reliability electrical and structural insulating components for ground, marine, and aviation systems.
Automotive, EV & Heavy Vehicle Manufacturing
Battery insulation, electrical system components, fire-resistant panels, and non-conductive structural parts.
Industrial Machinery, Automation & Robotics
Precision machined components, insulating supports, jigs, fixtures, guides, and structural dielectric elements.
Oil, Gas, Mining & Petrochemical Operations
Corrosion-resistant insulating parts for refineries, processing plants, pump stations, and hazardous area equipment.
Heating, Oven, Furnace & Thermal Processing Equipment
Heat-resistant insulating structures for furnaces, ovens, kilns, induction systems, and high-temperature machinery.
Electronics, Semiconductor & High-Tech Manufacturing
Electrical isolation plates, control panels, machine insulators, and clean-room compatible dielectric components.
Construction, Infrastructure & Building Services
Electrical distribution components, fire-retardant insulation panels, and building-services electrical systems.
Marine, Shipbuilding & Offshore Energy
Salt-resistant insulating boards, switch gear components, and power-distribution elements for marine environments.
Data Centres & Critical Infrastructure
UPS systems, control cabinets, power distribution components, and flame-retardant insulation structures.

Improves electrical safety and reliability
High dielectric strength and tracking resistance reduce the risk of phase-to-phase faults, arcing, and breakdown in power equipment.
Enhances fire safety and compliance
UL 94 V-0 self-extinguishing performance supports safe use in enclosed switchboards, substations, rail rolling stock, and defence systems.
Reduces failure rates in harsh environments
Stable under heat, humidity, vibration, and contamination—ideal for industrial, mining, rail, and outdoor power applications.
Delivers strong mechanical stability under load
High flexural and compressive performance allow the material to function as both an insulator and a structural component.
Supports lightweight system design
Provides the strength of metal components without the weight penalty, improving handling and reducing installation loads.
Maintains dimensional accuracy over time
Low moisture uptake and excellent thermal stability ensure long-term tolerance control for precision-machined parts.
Minimizes corrosion and maintenance requirements
Glass-reinforced polyester does not rust, swell, or degrade in the presence of oils, coolants, or industrial contaminants.
Improves machinability and production efficiency
Clean CNC machining with predictable tool behavior enables complex shapes, tight tolerances, and repeatable batch parts.
Supports modern environmental and regulatory standards
Halogen-free, asbestos-free, RoHS/REACH compliant materials assist with compliance obligations in defence, rail, and energy sectors.
Reliable performance across multiple industries
A trusted, proven insulating composite for switchboards, transformers, motors, power systems, renewables, and critical infrastructure.
Enables consistent, traceable manufacturing quality
Stable resin systems, controlled press cycles, and verifiable batch records support quality management and ISO-aligned processes.
Compatible with Australian and international standards
Helps OEMs and installers meet AS/NZS, IEC, NEMA, UL, and industry-specific electrical insulation and fire-performance requirements.

Downloads

All supporting documents for this material are available for download, including the latest technical data sheet, safety data sheet, machining and processing guidance, compliance information, and relevant product brochures.

These controlled documents provide specifications, performance data, handling requirements, and application notes to assist with design, material selection, and fabrication.

Each file is maintained by MISCO Australia to ensure current, reliable information for switchboard, transformer, industrial, and defence grade applications.

Frequently Asked Questions

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