Cable tray parallel at 70 degrees

When installing cable trays in parallel at an angle, maintain a minimum spacing of 0.6 meters to ensure proper airflow, maintenance access, and safety.

Parallel Tray Spacing

For cable trays installed in parallel, the minimum horizontal distance between trays should generally be 0.6 meters (approximately 2 feet). This spacing ensures adequate room for maintenance, inspection, and heat dissipation, and reduces the risk of cables touching or causing short circuits . If the trays carry both power and signal cables, a minimum separation of 0.5 meters is recommended to minimize electromagnetic interference (EMI), which can be reduced further if the trays are shielded .

Considerations for Angled Installation

Installing trays at a 70-degree angle does not change the minimum spacing requirement, but it affects cable support and stability:

• Ensure that the trays are mechanically supported along the angled run to prevent sagging or stress on cables .
• Use hanging rods or brackets rated for the tray load, especially for ladder-type trays, to maintain structural integrity .
• Verify that the angle does not compromise access for inspection or maintenance, as technicians need sufficient clearance to safely work on the cables.

Cable Fill and Derating

When multiple conductors are installed in parallel trays:

• Follow NEC Article 392 for tray fill limits and ampacity adjustments .
• Multiconductor cables with three or fewer current-carrying conductors do not require additional derating per NEC 310.15(C)(1) when installed in trays .
• Ensure that the tray type (ladder, ventilated trough, or solid-bottom) is suitable for the cable size and heat dissipation requirements .

Best Practices

• Maintain vertical and horizontal clearances to allow airflow and prevent overheating.
• Avoid overfilling trays, especially at angles, to reduce stress on cables and maintain proper ventilation.
• Consider shielding for signal cables to allow closer spacing without EMI issues.
• Regularly inspect angled tray runs for mechanical stability and cable integrity. By following these guidelines, parallel cable trays at a 70-degree angle can be installed safely, maintain proper airflow, and comply with NEC standards for spacing and ampacity .