Why Non-Metallic FRP Cable Supports Are a Smart Choice for Underground Power Systems

Why Non-Metallic FRP Cable Supports Are a Smart Choice for Underground Power Systems

Discover why non-metallic FRP cable supports are ideal for underground power systems, offering corrosion resistance, electrical insulation, high strength, and low maintenance.

Underground power infrastructure creates a demanding environment for cable support systems.

Cable brackets installed inside cable trenches, utility tunnels, manholes, underground vaults and industrial cable corridors may be continuously exposed to moisture, condensation, groundwater, corrosive gases and restricted maintenance conditions.

For decades, steel cable racks and brackets have been widely used in these applications. However, corrosion, electrical conductivity and maintenance requirements have encouraged engineers and contractors to consider non-metallic cable support systems as an alternative.

Among these solutions, FRP (Fiberglass Reinforced Plastic) cable supports combine electrical insulation, corrosion resistance, mechanical strength and lightweight construction, making them particularly suitable for underground power and infrastructure projects.

What Are Non-Metallic Cable Supports?

Non-metallic cable supports are brackets, arms, racks or support structures manufactured from materials that do not rely on conventional steel as their primary structural material.

They are commonly used to support:

Depending on the system design, non-metallic supports may be mounted directly onto concrete walls or combined into multi-level cable support systems.

In the U.S. market, non-metallic cable support systems are already promoted specifically for manholes, tunnels, underground vaults, utility corridors and retrofit projects, with corrosion resistance and electrical insulation positioned as important benefits.

FRP cable supports provide many of these same advantages while offering the additional benefit of fiberglass reinforcement for structural applications.

1. Corrosion Resistance in Underground Environments

Corrosion is one of the most important reasons to consider non-metallic cable supports.

Underground cable installations often experience:

Steel brackets normally require galvanizing, protective coatings, painting or other corrosion protection systems.

Once these protective layers become damaged, corrosion can gradually affect the bracket.

FRP behaves differently.

Fiberglass reinforced plastic does not rust in the same way as carbon steel. With an appropriate resin system, FRP cable brackets can therefore provide reliable performance in humid and corrosive environments with significantly less dependence on protective surface coatings.

This makes FRP particularly attractive for:

For infrastructure owners, the benefit is not simply corrosion resistance itself.

The larger advantage is the potential to reduce inspection, repainting, coating repair and corrosion-related replacement during the service life of the cable support system.

2. Electrical Insulation Is Built Into the Material

Steel is electrically conductive.

FRP, by comparison, is a non-metallic composite with good dielectric and electrical insulation properties.

This characteristic is particularly valuable around power cables and electrical infrastructure.

Non-metallic cable support manufacturers in the U.S. specifically highlight electrical non-conductivity and dielectric properties as key advantages of their systems. Some systems can also reduce the need for separate insulating components, although actual grounding and bonding requirements must always be determined by the complete installation design and applicable electrical codes.

For engineers, this means the support material itself can contribute to electrical isolation rather than introducing another conductive component into the cable system.

This can be especially useful in:

3. High Load Capacity Without the Weight of Steel

One common misunderstanding about non-metallic cable brackets is that they must be suitable only for lightweight cables.

That is not necessarily the case.

Properly engineered composite cable supports can provide substantial structural capacity. In the U.S. market, heavy-duty non-metallic cable racks are specifically marketed as providing load capacity comparable with corresponding steel cable racks.

For FRP cable supports, load capacity depends on several factors, including:

Pinzheng FRP cable supports are manufactured using SMC compression molding, allowing fiberglass reinforcement and resin to be molded into a consistent structural component.

Depending on the bracket structure and installation conditions, our current FRP cable support designs can provide load capacities up to approximately 300 kg.

For actual projects, however, cable support selection should always be based on the required working load, bracket spacing, safety factor and installation method rather than simply choosing a support by material.

4. Lightweight Construction Makes Installation Easier

Underground installation is often more difficult than installation in an open industrial building.

Workers may need to move brackets through:

Heavy metal components increase handling difficulty.

FRP provides a high strength-to-weight ratio, allowing structural brackets to remain relatively lightweight while maintaining useful mechanical strength.

Lower component weight can help simplify:

Across hundreds or thousands of cable support locations, even relatively small reductions in component weight can make installation more convenient.

5. Suitable for Both New Construction and Retrofit Projects

Cable infrastructure is not limited to new construction.

Many utility companies, industrial facilities and infrastructure operators need to replace or upgrade aging cable support systems inside existing tunnels and underground structures.

This makes retrofit compatibility increasingly important.

Non-metallic wall-mounted supports can be particularly useful because individual support arms can often be installed directly onto existing concrete structures.

This approach is already used by non-metallic support systems marketed for both new installations and retrofit projects in underground vaults and manholes.

FRP brackets can similarly be designed around:

For renovation projects, customized bracket dimensions may allow engineers to upgrade the cable support system without completely redesigning the underground structure.

6. Modular Designs Make Cable Layouts More Flexible

Not every cable trench requires the same support configuration.

Some projects may need only one layer of cables.

Others may require several levels of power, control and communication cables running through the same corridor.

For this reason, modular cable support systems offer important advantages.

FRP support arms can be configured into:

This allows the system to be adapted according to cable quantity and project layout rather than forcing every project to use the same bracket configuration.

Modular construction can also simplify future cable additions or system expansion.

FRP Cable Supports vs Steel Cable Supports

FeatureFRP Cable SupportsSteel Cable Supports
Corrosion resistanceDoes not rust like steelUsually requires corrosion protection
Electrical conductivityNon-conductive materialConductive
WeightLightweightRelatively heavy
Underground humidityWell suitedProtection may be required
MaintenanceGenerally lowCoatings may require maintenance
Modular designAvailableAvailable
Heavy-load capabilityAvailable with engineered designExcellent
Chemical environmentsStrong advantage with suitable resinDepends on coating/material
Custom moldingSuitable for SMC productionUsually fabricated or formed

Neither material is automatically the correct choice for every project.

Steel remains suitable for many extremely heavy structural applications.

However, when the project involves humidity, corrosion, electrical insulation, limited maintenance access or large quantities of underground cable supports, FRP becomes particularly attractive.

Where Are FRP Cable Supports Typically Used?

FRP cable brackets can be considered for many infrastructure and industrial cable systems, including:

Cable Trenches

One of the most common applications.

Supports are fixed along the trench walls to organize cables at different levels while keeping them away from the bottom of the trench.

Utility Tunnels

Long tunnels may contain large quantities of power and communication cables.

Corrosion resistance and reduced maintenance can become increasingly valuable as the length of the installation increases.

Underground Utility Vaults and Manholes

These spaces frequently experience moisture and condensation while offering limited maintenance access.

Non-metallic supports are already commercially used for this type of underground infrastructure in the U.S. market.

Substations

FRP's insulation characteristics make it suitable for cable management around electrical distribution infrastructure.

Metro and Railway Infrastructure

Tunnels and underground stations require durable cable support systems capable of operating for long periods in difficult-to-access locations.

Chemical and Wastewater Facilities

These environments may expose supports to moisture and corrosive chemicals, making corrosion-resistant composite materials particularly useful.

Coastal Infrastructure

Salt and humidity can accelerate corrosion of conventional metal components, increasing the value of corrosion-resistant support materials.

Why SMC Compression Molding Matters

Material choice is only one part of cable bracket performance.

The manufacturing process is equally important.

Our FRP cable supports are manufactured through SMC compression molding.

SMC — Sheet Molding Compound — combines resin, fiberglass reinforcement, fillers and additives into a material that can be compression molded under controlled temperature and pressure.

For cable support production, this process provides several important advantages:

This makes SMC especially suitable for infrastructure projects that may require hundreds, thousands or even tens of thousands of identical cable support components.

Choosing the Right Non-Metallic Cable Support

When specifying FRP cable supports, buyers should not evaluate only the bracket dimensions.

Several engineering factors should be confirmed before production.

These include:

Required load

Calculate cable weight and determine the required safety margin.

Support arm length

Longer arms create greater bending moments and may require stronger structural designs.

Bracket spacing

The distance between supports directly affects the load carried by each bracket.

Installation environment

Humidity, chemicals, outdoor exposure and operating temperature should be considered when selecting the resin system.

Mounting method

Concrete wall anchors, mounting holes and fixing hardware must match the project structure.

Cable arrangement

Determine whether single-level, double-level or multi-level support systems are required.

For custom projects, providing cable weight, bracket spacing, installation drawings and required load information allows the manufacturer to recommend a more appropriate structure.

Can FRP Cable Supports Replace Steel?

In many cable support applications, yes — but the decision should be engineering-based.

The question should not simply be:

“Is FRP stronger than steel?”

A better question is:

“Can this FRP bracket safely carry the required cable load in this specific environment?”

If the answer is yes, FRP can provide additional advantages that steel may not offer, particularly:

For underground power infrastructure, these properties can make FRP a practical long-term alternative to conventional metal cable supports.

Custom SMC FRP Cable Supports from Pinzheng

Pinzheng manufactures SMC molded fiberglass cable supports and custom FRP brackets for electrical, industrial and infrastructure projects.

We can support project-specific requirements including:

For new projects, customers can provide drawings or technical requirements.

For retrofit projects, existing bracket dimensions, photographs and installation information can also be used as a starting point for evaluation.

Frequently Asked Questions

Are FRP cable supports non-conductive?

FRP is a non-metallic composite material with good electrical insulation properties. This makes FRP cable supports particularly suitable for electrical and power infrastructure where reducing conductive components can be beneficial.

Do FRP cable brackets rust?

FRP does not rust like carbon steel. This is one of its main advantages in underground, humid, coastal and chemically exposed environments.

Can FRP cable supports carry heavy power cables?

Yes. Properly designed fiberglass reinforced supports can carry substantial cable loads. Actual capacity depends on bracket geometry, material formulation, arm length, mounting method and installation conditions.

Pinzheng's current SMC cable support designs can reach approximately 300 kg depending on configuration and installation conditions.

Where can non-metallic cable supports be used?

Typical applications include cable trenches, utility tunnels, underground vaults, manholes, substations, industrial plants, wastewater facilities, metro systems and other electrical infrastructure.

Can FRP brackets be customized for an existing cable tunnel?

Yes. Dimensions, arm length, mounting holes, support levels and load capacity can be customized according to existing installation conditions.

Are FRP cable supports suitable for retrofit projects?

Yes. Wall-mounted FRP supports can be designed according to existing concrete structures and cable layouts, making them suitable for both new installations and replacement projects.

Conclusion

Underground cable infrastructure requires more than simply a strong bracket.

The support system must operate reliably in an environment that may be wet, corrosive, electrically sensitive and difficult to maintain.

This is why non-metallic cable supports are increasingly worth considering for underground power systems.

FRP combines fiberglass reinforcement with the advantages of a non-metallic material, providing corrosion resistance, electrical insulation, lightweight construction and engineered load-bearing capability.

For cable trenches, utility tunnels, vaults, substations and industrial cable corridors, SMC molded FRP supports can provide a durable alternative to conventional steel cable brackets.

Looking for FRP cable supports for your project?

Pinzheng provides SMC molded fiberglass cable brackets and customized FRP support solutions for underground power, tunnel and industrial applications.

Send us your bracket dimensions, required load, cable arrangement or project drawing for evaluation.