Fixed Spacing of Vertical Sections of Cable Trays

Vertical cable trays should generally be supported at intervals of 1.5 to 2 meters, with additional strain relief for long runs.

Standard Support Intervals

For vertical cable tray installations, supports should be fixed to the building structure at intervals preferably less than 2 meters to maintain stability and prevent sagging or stress on the cables . In practice, many installations secure cables at the top and then at every 1.5 meters along the vertical run . This spacing ensures that the tray remains structurally sound and that cables are properly restrained.

Considerations for Long Vertical Runs

• Strain Relief Sections: For vertical runs exceeding 32 meters, strain relief sections should be incorporated. This typically involves offsetting the cable by at least 2 cable diameters at each strain relief point .
• Excessive Runs: For runs over 100 meters, additional measures such as short horizontal sections (at least 1 meter) are recommended to relieve tension and prevent cable damage .

Manufacturer and Standard Guidelines

• IEEE Std 525-1992 recommends supporting vertical copper conductor cables according to specified intervals, with special cables (armored, shielded, coaxial) requiring manufacturer guidance .
• NEMA VE-2 and typical manufacturer catalogs suggest that steel cable trays up to 6 inches deep can be self-supporting for vertical sections up to 20 feet, but must be fastened to walls or columns to resist horizontal forces .

Practical Installation Tips

• Ensure cables are secured at intermediate locations to prevent movement within the tray .
• At bends or transitions, supports should be placed on either side to maintain the minimum bending radius .
• For flexible systems (e.g., J-hanger installations), calculations may be required to determine support spacing based on deflection and load .

Summary

• Typical vertical support spacing: 1.5–2 meters
• Long runs (>32 m): Include strain relief sections
• Very long runs (>100 m): Add horizontal sections for tension relief
• Manufacturer guidance: Always follow tray and cable manufacturer recommendations for special cable types and structural considerations This approach ensures structural integrity, cable safety, and compliance with industry standards while allowing for future maintenance and expansion.