Non-Conductive Cable Trays for Chemical Plants and Substations
Non-conducting cable trays made from fibre-reinforced plastic (FRP) are common in chemical plants and substations due to their electrical insulating, corrosion resistant and low maintenance qualities. While compared to metal trays, FRP cable trays help to minimize maintenance costs associated with corrosion problems and eliminate the need for the use of a conductive metal tray frame, they do not serve as substitutes to electrical insulations and other protective mechanisms that are needed according to the installation design.
Cable tray designs in chemical plants have to withstand corrosion fumes, moisture and chemical spillages, while the selection of an appropriate cable tray design in the case of substations should take into account electrical insulating and environmental challenges.
What Are Non-Conductive Cable Trays?
Non-conductive cable trays are cable management systems that are made from non-conductive materials. For example, FRP cable trays incorporate glass fibre within polymer resins in order to create electrical and mechanical stability.
FRP cable trays may offer the following advantages depending on the design and material composition:
- Low electrical conductivity
- Corrosion resistance to various aggressive environments
- Less heavy than steel constructions
- Resistance to rust
- Use in both indoor and outdoor applications
- Various sizes and configurations available
Performance characteristics are determined by specific product specifications. Therefore, it would be wrong to assume all FRP products to have specific dielectric properties, fire resistance and chemical compatibility.
Why Are FRP Cable Trays Used in Chemical Plants?
Chemical processing plants could contain acids, alkalis, solvents, moisture and corrosive fumes, which could affect normal metal cable support structures unless the metal and coating used are appropriate for such an environment.
FRP cable trays could provide a solution when the chosen resin system is compatible with the chemicals and temperatures present.
1. Corrosion Resistance
The corrosion process cannot affect FRP in the same way that carbon steel is affected. It means that an appropriately engineered FRP cable tray can be used in numerous corrosive applications.
Chemical resistance depends, however, on the resin type, temperature, concentration and time of exposure to chemicals. Compatibility should be checked before the installation, especially when the tray is exposed to oxidizing chemicals.
2. Non-Conductive Construction
FRP cable trays have an insulating nature in general when compared with metal cable trays. This may be good for certain applications where the absence of the conductivity of the tray itself is necessary.
Nevertheless, the presence of such a tray will not ensure that the overall electrical installation is safe. The other elements such as cable insulation, protection, earthing, and other electrical criteria must still be considered.
3. Reduced Corrosion-Related Maintenance
The metal trays, subjected to severe environments, need inspection, coatings or replacement due to corrosion. Appropriate FRP trays minimize such maintenance due to corrosion.
Inspections should be carried out regularly to detect damage, any loose support structure, deflection and any deterioration due to UV or improper chemicals.
4. Lightweight Construction
FRP cable trays tend to be lightweight compared to their equivalent steel cable trays, which can facilitate their installation process.
All these aspects need to be taken into consideration when designing the whole cable tray support system.
Why Consider Non-Conductive Cable Trays for Substations?
Substations will house power, control, protection, instrumentation, and communication cables which shall need proper routing and support to satisfy the requirements of the project.
The use of FRP cable trays may be thought of for certain applications that require resistance to corrosion, low conductivity, and lightness of construction.
Some possible applications are:
- Control and instrumentation cable routing
- Protection and communication cable routing
- Cable support systems for outdoor use
- Auxiliary electrical facilities
- Areas where corrosion may affect metallic cable support systems
Important Electrical Safety Considerations
Substations will require the presence of electrical potentials, including ground potential rises and transient events caused by faults. The application of FRP trays should never be used as a replacement for earthing and bonding systems.
Before installing FRP cable trays, the following should first be established by the project engineer:
- Cable electrical separation and segregation required
- Earthing and bonding needs of the metallic items
- Faults and short circuits
- Fire and smoke requirements
- Mechanical support and protection of the cables
- Relevant electrical and utilities standards
The proper selection of cable trays should be based on the whole installation process and not whether the tray itself is conductive or not.
FRP vs Metal Cable Trays: What Is the Difference?
| Feature | FRP cable trays | Galvanised steel cable trays |
|---|---|---|
| Electrical conductivity | Generally non-conductive | Conductive |
| Corrosion resistance | Depends on the resin and chemical exposure | Depends on the coating, environment and corrosion protection |
| Weight | Often lighter than comparable steel systems | Generally heavier |
| Maintenance | Can reduce corrosion-related maintenance | May require coating inspection and corrosion control |
| Mechanical performance | Depends on profile, reinforcement and span | Depends on steel thickness, profile and support spacing |
| Outdoor use | Requires appropriate UV and weathering performance | Requires suitable corrosion protection |
| Chemical environments | Suitable when the selected FRP system is chemically compatible | Suitability depends on the metal, coating and chemical exposure |
| Electrical protection | Does not eliminate other electrical protection requirements | May require grounding and bonding as specified by the design |
Neither material is automatically the best choice for every project. Compare the manufacturer’s load data, environmental suitability, installation requirements and total lifecycle cost before deciding.
How to Select the Right Non-Conductive Cable Tray
Choosing a cable tray solely on its cost and size may pose challenges during installation and maintenance. Take into account the following considerations when ordering one.
1. Cable Load and Tray Dimensions
Determine the total weight of the cables, taking into account the future expansion if necessary. Determine the tray width, height, the distance between supports, and allowable deflection from the technical literature of the manufacturer.
Never consider two identical trays as having the same load capacity.
2. Chemical Compatibility
Identify the potential chemical interactions on the tray, taking into account the vapors, splashes, cleaning solvents, and spills.
Verify with the manufacturer that the resin system is suitable for the specific concentration, temperature, and exposure time.
3. Outdoor and UV Exposure
In case of outdoor installation, test for ultraviolet light resistance, weathering capability, and compatibility of the tray to the surrounding environment.
Wind loading, thermal expansion, water accumulation, and supports should also be considered.
4. Fire Performance
Fire and flame spread, as well as smoke characteristics, exist for some chemical plants and substations. Ensure that you get the specifications relevant to your project and the test data that support your tray choice.
FRP products are not necessarily fire-resistant.
5. Fittings and Installation Accessories
Check the availability of bends, tees, reducers, caps, connectors, and mounting accessories. Make sure that the joining and installation techniques for the chosen product are appropriate.
6. Standards and Technical Documentation
Review the standards and acceptance criteria defined for the project. Obtain drawings, load tables, materials data and test results from the vendor.
For substations, select a tray in consultation with the electrical engineer and the requirements of the particular utility or project owner.
Where Can FRP Cable Trays Be Installed?
In line with the product specification details, the FRP cable tray can be appropriate for:
- Chemical and pharmaceutical production industries
- Water treatment facilities
- Humid coastal locations
- Power generation stations
- Control and instrumentation systems of industry
- Outdoor cable runs that need corrosion resistance
The installation location needs to be considered prior to deciding on the product. There could be major differences regarding temperature, chemical exposure, and fire ratings from application to application.
Why Consider Plastic Fabricators for FRP Cable Trays?
The Plastic Fabricators Company provides FRP cable trays that can be used in the industry for effective management of cables and corrosion resistance.
In case of selecting a tray for use in chemical plants or substations, you should first provide all the necessary information such as dimensions, loading, supports and installation environment.
Consider the available products and make sure that they meet your requirements before purchasing the tray.
Explore the FRP Cable Trays range from Plastic Fabricators.
Conclusion
FRP cable trays that are non-conductive may be considered for application in chemical plant situations and particular substation installations, where issues of corrosion resistance, lightness, and lower electrical conductivity matter. The performance will depend on the material specification, loading of cables, support spacing, environmental exposure, and method of installation.
When considering the use of FRP over galvanized steel, take into account the whole operational environment and check the technical specifications provided by the manufacturer. Where substations are concerned, the choice should conform to all requirements of the project.
Plastic Fabricators offers FRP cable trays for industrial applications. Contact the company with your project dimensions and technical requirements to discuss a suitable cable-management solution.