What type of cable tray should be used for a 185mm cable

A ladder-type cable tray is generally recommended for a 185mm power cable due to its superior ventilation, heat dissipation, and mechanical support.

Why Ladder Trays Are Preferred

For large-diameter power cables like a 185mm cable, heat dissipation and mechanical support are critical. Ladder trays consist of two longitudinal side rails connected by transverse rungs, allowing maximum airflow around the cables, which helps prevent overheating and prolongs insulation life . They also provide convenient points to tie down and secure heavy single-conductor cables, which is essential for maintaining proper cable positioning and safety . Ladder trays are widely used in industrial and utility-scale installations and are suitable for single-conductor and Type MV cables, which are not allowed in solid bottom trays according to NEC guidelines .

Alternative Tray Types

• Ventilated Trough Trays: These trays have perforated bottoms and sides, offering some ventilation while providing more support than solid trays. They can be used for large cables but are less common for very heavy single-conductor runs .
• Solid Bottom Trays: These provide full support and protection but limit heat dissipation, making them less suitable for high-current, large-diameter cables unless environmental protection is required .
• Wire Mesh (Basket) Trays: Lightweight and flexible, ideal for small or medium cables, but not recommended for heavy 185mm power cables due to limited mechanical strength .

Sizing Considerations

When installing a 185mm cable, ensure the tray width and rung spacing accommodate the cable's bend radius and fill factor. IEC 61537 and manufacturer guidelines recommend calculating the total cable cross-sectional area and ensuring the tray can support the weight and maintain proper spacing for heat dissipation . Ladder trays typically allow long spans (10–24 ft) without intermediate support, which is advantageous for large cables.

Summary Recommendation

For a 185mm power cable, a ladder-type cable tray is the most suitable choice due to:

• Maximum ventilation and heat dissipation
• Strong mechanical support for heavy cables
• Compliance with NEC for single-conductor and Type MV cables
• Ease of securing and maintaining cable positions

If environmental protection is required, a ventilated trough tray may be considered, but solid bottom trays should generally be avoided for high-current large cables unless specific protection is needed .