How long is the cable fixing point to the cable tray

Cable tray fixing points are typically spaced up to 3.6 meters apart, with closer spacing required for heavy loads or specific installation conditions.

Horizontal Tray Support Spacing

For standard ladder or ventilated trough cable trays, the maximum support spacing is generally 3.6 meters (12 feet) for center-hung or side-hung installations, depending on the tray type and load capacity . For example, a 6-meter tray would typically have supports approximately 1.5 meters from each end to ensure stability and prevent sagging . The spacing may need to be reduced if the tray carries heavy power cables, large bundles, or sensitive instrumentation cables .

Vertical Runs and Strain Relief

Vertical cable runs require special attention to prevent excessive mechanical strain. For vertical runs exceeding 32 meters, strain relief sections should be incorporated, typically by offsetting the cable by at least two cable diameters per section . For very long vertical runs (over 100 meters), additional measures such as short horizontal sections of at least 1 meter are recommended to relieve tension and prevent displacement .

Load Considerations

Each hanger or support has a maximum load capacity, often ranging from 318 kg to 340 kg (700–750 lbs) per support . The actual spacing should be adjusted based on the total weight of the cables, tray type, and environmental factors. Flexible systems, such as J-hanger installations, require calculations to determine support spacing to achieve acceptable deflection and prevent cable displacement .

Summary Recommendations

• Standard horizontal tray: maximum 3.6 m between supports, with end supports ~1/4 of tray length from ends .
• Heavy or large cable loads: reduce spacing below 3.6 m.
• Vertical runs >32 m: include strain relief offsets of 2 cable diameters .
• Vertical runs >100 m: add horizontal sections of at least 1 m to relieve tension .
• Flexible or suspended systems: calculate spacing based on deflection and load . Following these guidelines ensures mechanical stability, compliance with electrical codes, and safe cable installation.