Electrical insulation materials play a critical role in the safety, reliability and compact design of switchgear. In North American switchgear applications, materials are often required to provide a combination of flame resistance, high CTI, arc resistance, electrical insulation and mechanical strength.

Among the materials used for these demanding applications, GPO-3 insulation board is widely selected for busbar supports, phase barriers, arc barriers and other structural insulation components.

Why GPO-3 Is a Preferred Material for Switchgear

GPO-3, also known as UPGM-203, is a glass-fiber-reinforced polyester insulation material. It combines high mechanical strength with excellent electrical insulation, flame resistance and arc resistance.

Compared with general-purpose insulating materials, it is particularly attractive for switchgear because it can provide both electrical insulation and mechanical support. This can help reduce the number of supporting components while allowing more compact equipment designs.

For North American electrical equipment, flame resistance and ignition performance are especially important. UL material evaluations commonly include performance characteristics such as Hot Wire Ignition (HWI), High Ampere Arc Ignition (HAI) and Comparative Tracking Index (CTI).

Understanding HWI, HAI and CTI

Hot Wire Ignition (HWI) evaluates the resistance of a polymeric material to ignition when exposed to a heated wire. The material is classified according to the time required for ignition. Under the UL performance-level classification, PLC 0 represents the highest performance level, with an ignition time greater than 120 seconds.

High Ampere Arc Ignition (HAI) evaluates a material's resistance to ignition when exposed to high-current electrical arcs. The material classification is based on the number of arc applications required to cause ignition. A lower PLC number indicates better resistance to ignition, with PLC 0 representing the highest performance category.

CTI measures the ability of an insulating material to resist the formation of a conductive path when subjected to electrical stress in the presence of moisture and contaminants. Under the UL classification system, CTI values of 600 V or higher correspond to PLC 0.

These properties are particularly important in switchgear because insulation components may be exposed to electrical stress, heat, moisture, contamination and potential arcing during operation.

GPO-3 in Low-Voltage Switchgear

Modern low-voltage switchgear often requires a high level of integration, with multiple circuit breakers and busbar systems installed within a limited space.

GPO-3 can be used for busbar supports, phase barriers, insulation barriers and other structural components. Its high mechanical strength provides reliable support for busbars while its electrical insulation properties help maintain the required separation between energized components.

For equipment rated around 600 V, creepage and clearance requirements must be determined according to the applicable product standard, voltage, pollution level and system design. In certain switchgear designs, maintaining sufficient air clearance and creepage distance is essential, while GPO-3 barriers can provide an additional level of electrical separation and protection.

Its rigid structure also allows designers to develop compact and mechanically stable insulation assemblies.

GPO-3 for Medium-Voltage Switchgear

GPO-3 is also used in medium-voltage switchgear for applications involving high-voltage fuses, switches, phase barriers and protective insulation barriers.

In these systems, an insulation barrier can help separate energized components from adjacent phases or grounded structures. Even when the required clearance is already achieved, an additional GPO-3 barrier may be used to improve electrical separation and help limit the potential spread of an internal arc event.

Its high arc resistance is particularly valuable in switchgear applications where electrical faults can generate intense heat and arcing. Properly designed insulation barriers can help contain or limit the effects of an electrical fault and reduce the risk of damage spreading to adjacent compartments.

GPO-3 in Compact Outdoor Switchgear

Compact outdoor switchgear is designed to provide reliable electrical distribution while minimizing equipment size and simplifying inspection and maintenance.

In some air-insulated switchgear designs operating at 15 kV, 27 kV and similar medium-voltage levels, glass-fiber-reinforced polyester barriers can be used to separate compartments, isolate busbar connections and prevent accidental contact with energized components.

GPO-3 front barriers can provide both electrical insulation and mechanical protection. Their rigid construction allows them to function as structural barriers while maintaining reliable separation between high-voltage components and accessible areas.

Choosing the Right GPO-3 for Switchgear

Selecting an insulation material for switchgear should not be based on a single parameter. Flame resistance, CTI, dielectric strength, arc resistance, mechanical strength, temperature resistance and environmental conditions should all be considered together.

The specific UL recognition, PLC ratings and electrical performance should also be verified for the exact GPO-3 grade and thickness being used. Different formulations can have different performance levels, so the material should always be selected according to the requirements of the final equipment and applicable standards.

High-quality GPO-3 insulation can help switchgear manufacturers achieve compact designs, reliable electrical separation and improved resistance to heat, moisture and electrical arcing.

GPO-3 Insulation Components from YILONG

YILONG supplies GPO-3 / UPGM-203 insulation boards and customized machined insulation components for switchgear, circuit breakers, motors, transformers and other electrical equipment.

It can be supplied as sheets or processed into customized busbar supports, phase barriers, arc barriers, insulation plates and structural components according to customer drawings and application requirements.

For technical data, samples or customized switchgear insulation components, please contact YILONG.

Website: www.yilonginsulation.com
Email: yilong@yilonginsulation.com
WhatsApp: +86 15866869385