Tunnel-type cable trays

Tunnel cable trays come in several types, including ladder, perforated, wire mesh, solid-bottom, and GRP trays, each designed to meet specific load, ventilation, and safety requirements.

Ladder Cable Trays

Ladder trays consist of two side rails connected by rungs, forming an open structure that allows excellent ventilation and heat dissipation. They are ideal for large power routes, main distribution cables, and long utility corridors in tunnels, supporting heavy loads and enabling easy inspection and cable pulling ( ). Their modular design allows them to navigate bends, inclines, and drops without major tunnel modifications ( ).

Perforated Cable Trays

Perforated trays have a solid bottom with regularly spaced holes, providing continuous cable support while allowing limited airflow. They are suitable for lighting circuits, control cables, and auxiliary systems where a more enclosed appearance is preferred ( ). These trays balance support and ventilation, making them versatile for medium-load applications.

Wire Mesh (Basket) Trays

Wire mesh trays, also called basket trays, are lightweight and flexible, ideal for low-voltage, communication, or fiber optic cables in accessible service areas ( ). Their open design allows easy routing and modifications, and they are particularly useful in tunnels with tight spaces or complex layouts ( ).

Solid-Bottom and Trough Trays

Solid-bottom or trough trays provide maximum protection against moisture, dust, and mechanical impact, making them suitable for sensitive communication, monitoring, and control cables ( ). They are often used in areas where environmental protection is critical, and drainage or condensation management must be considered.

GRP (Glass Reinforced Polyester) Trays

GRP trays are made from halogen-free, self-extinguishing materials with excellent corrosion resistance ( ). They are fire-safe and suitable for tunnels with strict fire safety regulations, supporting low-smoke, halogen-free cables. GRP trays are particularly advantageous in humid or chemically aggressive tunnel environments.

Key Considerations for Tunnel Cable Trays

• Load Handling and Separation: Heavy-duty trays allow proper spacing between power, communication, and signaling cables to prevent interference and ensure heat dissipation ( ).
• Fire Safety: Trays must comply with standards such as IEC 60332, NFPA 130, and EN 45545, using non-combustible materials to prevent flame spread ( ).
• Installation Flexibility: Modular designs enable installation along bends, slopes, and limited-access areas without civil modifications ( ).
• Environmental Resistance: Materials and finishes should withstand humidity, dust, vibration, and potential water seepage ( ). Tunnel projects often combine multiple tray types along a route, selecting each based on cable function, load, exposure, and maintenance needs to ensure safety, reliability, and compliance with regulations ( ).