FRP cable trays are used to support and route electrical cables in industrial environments where corrosion is a consideration. Installation follows the same basic sequence as other cable tray systems: support the tray for the intended load, align and connect the sections, install fittings correctly, and check the completed system. The main difference is that FRP has different structural, electrical, and fabrication characteristics, so support selection, connections, grounding, and field modifications need to be handled accordingly.

What Makes Up an FRP Cable Tray System

A typical FRP cable tray system can include straight ladder or perforated sections, horizontal and vertical bends, tees, crosses, splice plates, and support brackets. The tray is a composite structure made from glass fiber reinforcement and a resin matrix. Because its structural response differs from metallic tray, the selected support arrangement should be based on the tray configuration, intended cable load, span, and the design criteria for the project.

Support Spacing: Based on Tray Configuration and Load

There is no single support spacing that applies to every FRP cable tray. The appropriate spacing depends on factors such as tray width and geometry, load, span, support arrangement, and the structural capability of the selected tray system.

A narrow tray with a relatively light cable load may require a different support arrangement from a wider tray carrying heavier power cables. Support spacing should therefore be selected from the manufacturer's load and span information together with the project's allowable deflection and installation requirements.

Support locations should also account for changes in the tray system. Fittings, splice locations, and changes in direction can affect how loads are transferred and should be supported in accordance with the selected system's installation instructions rather than treated exactly like uninterrupted straight runs.

Fittings and Connections

FRP tray sections are normally joined with splice plates and fasteners specified for the tray system and installation environment. Hardware should be compatible with both the tray material and the surrounding conditions, particularly in corrosive service. When tightening connections, use the fastening method and torque requirements specified for the selected system. Excessive tightening can damage the laminate or connection area.

Bends, tees, and crosses are generally supplied as matched fittings for the tray system. Field modifications can be made where permitted, but drilled or cut areas should be finished and sealed as specified by the manufacturer. This helps protect the exposed laminate and maintain the intended condition of the tray after fabrication.

Grounding and Electrical Continuity

Standard FRP cable tray is non-conductive and should not be assumed to provide an equipment grounding path. Where the electrical design requires bonding or grounding associated with the tray installation, the required conductor, connection method, and termination details should be provided in accordance with the applicable electrical code and project design.

Some cable tray systems may incorporate specific provisions for electrical continuity, but these features are system-dependent. Verify the selected tray configuration before treating any part of the system as part of the grounding or bonding arrangement.

Field Cutting and Edge Sealing

On-site cutting is sometimes required to achieve the final tray length or accommodate field conditions. Use a cutting method suitable for fiberglass-reinforced laminate and follow the manufacturer's fabrication instructions.

After cutting or drilling, exposed laminate areas should be sealed with the material and method specified for the tray system. Proper finishing is particularly important where modified surfaces may be exposed to moisture or corrosive conditions.

Thermal Movement

FRP and metallic tray systems respond differently to temperature changes, and long tray runs may require provisions for thermal movement. Where expansion or contraction needs to be accommodated, use the joint arrangement, splice configuration, or expansion provisions specified for the selected tray system.

Intermediate supports should maintain the required vertical support while allowing movement where the system design calls for it. Long straight runs should therefore be installed according to the manufacturer's guidance for thermal movement rather than rigidly fixing every section in the same way.

Load and Installation Checks

After installation, inspect the tray for excessive deflection between supports and confirm that the installed arrangement remains within the project requirements. Check splice connections, fitting support, cut or drilled areas, and any required bonding or grounding connections.

It is also useful to verify that the installed tray configuration matches the design arrangement, particularly where field changes have affected support locations, fittings, or cable routing.

FRP cable tray installation is primarily a matter of matching the tray system to its intended load and span, supporting changes in configuration correctly, completing connections carefully, and handling grounding and field fabrication according to the applicable design requirements.