Cable tray What is the spacing between the support legs

For standard horizontal cable tray runs, support legs should typically be spaced 1.5 to 3 meters apart, with closer spacing required for heavy loads, bends, or vertical runs.

Horizontal Support Spacing

For straight horizontal sections, the distance between cable tray supports (legs or hangers) generally ranges from 1.5 meters to 3 meters depending on the tray type, material, and cable load. Heavy-duty or long-span trays may allow supports up to 6 meters or more, but this must be verified against the manufacturer's load capacity chart to prevent sagging or mechanical stress on the cables . At corners, bends, or T-junctions, supports should be installed on each side symmetrically to maintain stability .

Vertical and Angled Runs

For vertical cable tray runs, supports should be fixed to the building structure at intervals preferably less than 2 meters to ensure stability and prevent undue stress on the cables . When transitioning from horizontal to vertical runs, additional supports may be required to maintain structural integrity.

Special Considerations

• Hanging rod supports should have a minimum diameter of 8 mm and be placed at beam locations for robust stability .
• Cable type and weight affect support spacing: stiffer cables like MDPE may require greater spacing, while flexible cables like LSOH may allow shorter spans to maintain a maximum 2% deflection .
• Cable securing: Cables should be tied at the start, end, and turns, and every 3–5 meters along straight runs to prevent shifting and improve heat dissipation .
• Clearances: Maintain at least 12 inches (≈300 mm) of vertical clearance above trays for installation and maintenance access .

Compliance and Safety

Support spacing must comply with NEC 392 in the U.S. and relevant local standards such as BS 7671 in the U.K., ensuring that cables are not exposed to mechanical strain and that the tray system remains structurally sound . Proper spacing also facilitates airflow, heat dissipation, and future maintenance or expansion. In summary, 1.5–3 meters is typical for horizontal runs, less than 2 meters for vertical runs, and closer spacing is required at bends, heavy loads, or for stiffer cables. Always consult the tray manufacturer's specifications and local electrical codes to ensure safe and compliant installation.