How to make supports for climbing cable trays

Cable tray supports must be designed to securely hold the tray and cables, using brackets, hangers, or suspension systems that meet load and safety requirements.

Understanding Cable Tray Support Systems

Cable trays are rigid raceways designed to support and route electrical cables over long distances. Proper support is critical to prevent sagging, maintain alignment, and ensure safety. Supports can be mounted on ceilings, walls, floors, or steel structures, and must account for the weight of cables, future additions, and environmental factors such as vibration, wind, or corrosion.

Types of Supports

Wall and Support Brackets: Fixed to walls or vertical surfaces, these brackets hold the tray horizontally and are suitable for short spans or light loads. Suspended Supports: Rods or threaded hangers from ceilings or overhead structures allow trays to be suspended, ideal for long runs or heavy cable loads. Center Suspensions: Used for wide trays or long spans, providing support at intermediate points to prevent deflection.

Mounting Plates and Accessories: Plates can attach junction boxes or devices to the tray, while accessories like clamps and fasteners secure the tray to the support elements.

Materials and Construction

Supports are typically made from steel or stainless steel, with galvanization or coatings for corrosion protection. For harsh environments, GRP (glass-reinforced plastic) supports may be used due to their lightweight, corrosion resistance, and electrical insulation properties. The choice of material depends on load requirements, environmental conditions, and chemical exposure.

Installation Guidelines

Span and Load: Determine the maximum load of the tray including cables and future additions. Check manufacturer specifications for maximum span between supports to avoid excessive deflection. Attachment: Avoid cutting or drilling structural members without approval.

Use approved fasteners and mounting hardware to secure supports to the building structure. Alignment: Ensure trays are level and aligned to allow smooth cable routing. Use horizontal or vertical bends, T-pieces, and crossovers as needed.

Safety and Compliance: Follow NEC Article 392 or local electrical codes for spacing, grounding, and bonding requirements. Supports must withstand mechanical and environmental stresses.

Practical Tips

For light cable loads, aesthetic and ruggedness may guide support selection. For heavy loads, consider structural calculations to ensure safety and economy. Use ventilated ladder trays for large power cables to allow heat dissipation, and solid or mesh trays for smaller control or instrumentation cables.

Regularly inspect supports for corrosion, loose fasteners, or deflection, especially in industrial or outdoor environments. By carefully selecting support types, materials, and installation methods, you can create a safe, durable, and code-compliant cable tray system suitable for climbing or elevated installations.