How to secure cable trays to a building

Cable trays are secured using supports such as ceiling-mounted trapeze hangers, wall-mounted brackets, or cantilever arms, with spacing and attachment methods determined by load, tray type, and building structure.

Support Methods

Cable trays are mounted using several common support methods depending on the building layout and tray route:

• Trapeze Hangers: These are horizontal supports suspended from ceilings using rods or threaded fasteners. They are ideal for long runs of cable trays in open spaces and allow multiple trays to be supported on a single trapeze assembly .
• Cantilever Wall Brackets: These brackets attach directly to walls and support trays running along vertical surfaces. They are suitable for sidewall installations or where ceiling suspension is not feasible .
• Ceiling or Roof Mounts: In some cases, trays are attached directly to structural beams or roof supports using clamps or threaded rods, ensuring stability and proper alignment .

Securing the Tray

Once the support method is chosen, the tray is secured using bolts, clamps, or brackets that attach the tray to the support structure. The tray sections are connected with hardware such as splice plates, bolts, and nuts to maintain mechanical integrity and continuity along the run . Proper alignment and leveling are critical to prevent sagging and ensure even load distribution.

Spacing and Load Considerations

The distance between supports, known as the support span, is determined by the tray type, material, and the total anticipated cable weight. Ladder-type trays, for example, may have longer spans due to their structural design, while solid-bottom trays may require closer spacing for heavier or sensitive cables . Overfilling a tray or exceeding its load capacity can lead to deformation, overheating, or mechanical failure, so adherence to manufacturer specifications and NEC guidelines is essential .

Compliance and Safety

Cable tray installations must comply with NEC Article 392, which specifies requirements for tray types, fill limits, grounding, and clearances. Metallic trays can serve as grounding conductors if properly bonded, and trays must remain accessible for maintenance . Nonmetallic trays, such as fiberglass-reinforced plastic (FRP), are used in corrosive or high-moisture environments and require appropriate attachment hardware compatible with the material .

Summary

Securing cable trays involves selecting the correct support method, attaching trays with appropriate hardware, maintaining proper support spacing, and following code requirements. Using trapeze hangers, wall brackets, or cantilever supports ensures mechanical stability, while careful planning prevents overloading and allows safe, organized routing of electrical and communication cables throughout the building .