What type of cable tray should be used for wire troughs

Ventilated or perforated trough cable trays are typically recommended for wire trough installations, providing continuous support while allowing moderate airflow.

Recommended Cable Tray Type

For wire troughs, the most suitable cable tray is a ventilated or perforated trough tray. These trays feature a continuous or partially ventilated bottom with solid side rails, offering continuous cable support without transverse rungs, unlike ladder trays, while maintaining moderate structural strength . They are ideal for small-diameter cables, such as control, instrumentation, and communication cables, which benefit from the continuous support that reduces mechanical stress on the cable jacket .

Advantages of Ventilated Trough Trays

• Continuous Support: Unlike ladder trays, the bottom surface supports the entire cable length, preventing sagging and mechanical damage .
• Moderate Ventilation: Perforations allow airflow to dissipate heat, which is important for maintaining cable insulation integrity .
• Flexibility: Suitable for mixed cable systems and installations where cable changes or additions are expected .
• NEC Compliance: Single conductor cables and Type MV cables are allowed in ladder or ventilated trough trays, but not in solid-bottom trays, making ventilated troughs compliant for these applications .

When to Avoid Solid-Bottom or Other Trays

• Solid-Bottom Trays: Provide maximum protection but restrict airflow, which can lead to overheating for certain cable types and are not permitted for single conductor or Type MV cables .
• Wire Mesh/Basket Trays: Lightweight and flexible, but better suited for low-voltage or fiber optic cables rather than main wire troughs .
• Channel Trays: Designed for small cable runs and light-duty applications, not for main trough installations .

Summary

For wire troughs, ventilated or perforated trough cable trays strike the best balance between mechanical support, airflow, and regulatory compliance. They are particularly effective for control, instrumentation, and communication cables, ensuring both safety and ease of maintenance while meeting NEC requirements .