Cable tray installation fixing bracket spacing table

Cable tray fixing brackets should be spaced according to tray type, material, and load, typically ranging from 1. 0 m to 3. 0 m, following standards like BS EN 61537.

Recommended Bracket Spacing

The spacing of cable tray fixing brackets depends on the tray type, material, and load. General guidance from industry standards and manufacturers is as follows: Steel Ladder Trays: Brackets are typically spaced every 2. 0 to 3.

0 meters for standard loads. Heavier cable loads may require closer spacing, around 1. 5 to 2.

0 meters. Aluminum Trays: Due to lower stiffness, spacing is usually 1. 5 to 2.

5 meters, depending on cable weight and tray width. Fiberglass or Composite Trays: Brackets are recommended every 1. 0 to 2.

0 meters, as these materials are less rigid and more prone to deflection. Mesh or Perforated Trays: Support spacing is generally 1. 0 to 2.

0 meters, with closer spacing for heavy or bundled cables.

Factors Affecting Bracket Spacing

Cable Load: Heavier cables require closer bracket spacing to prevent sagging and mechanical strain. Tray Width: Wider trays may need additional supports to maintain structural integrity. Environmental Conditions: Outdoor or corrosive environments may require more frequent supports to account for material degradation.

Short Circuit Forces: For power cables, spacing must consider forces generated during short circuits, which may necessitate closer bracket intervals. Cable Cleat Spacing on TraysWhen using cable cleats to secure cables within trays: Cleats should be installed every other rung for ladder-type trays, with a maximum spacing of 0. 3 meters on bends and 8–12 times the cable diameter for bend radius.

Not every cleat needs to be attached to the tray; unattached cleats provide additional restraint to keep cables bundled. Standards and ReferencesBS EN 61537: Specifies requirements for cable tray and ladder systems, including support spacing.

B

S 7671 Section 522. 8: Provides guidance on mechanical support of cables, emphasizing that cables must not suffer undue strain. Manufacturer-specific guides (e.g., OBO Bettermann, Legrand, Eaton) provide detailed tables for bracket spacing based on tray type, material, and load.

By following these guidelines, installers can ensure safe, compliant, and mechanically stable cable tray installations.