The recommended distance between parallel cable trays in trenches is generally at least 0.6 meters, with additional spacing considerations for heat dissipation, maintenance, and fire safety.

Horizontal Spacing

When installing two cable trays in parallel at the same height, the minimum horizontal distance should be 0.6 meters. This spacing ensures adequate access for maintenance, inspection, and proper airflow for heat dissipation, while also reducing the risk of cables touching and causing short circuits or interference (Apex Tray) . For power and signal cable trays laid in parallel, a minimum separation of 0.5 meters is recommended to minimize electromagnetic interference (EMI). If the trays are shielded, this distance can be reduced to 0.3 meters (Apex Tray) .

Vertical Spacing

For floor-mounted or stacked trays, the minimum vertical clearance between trays should be 150 millimeters. This allows for proper ventilation, heat dissipation, and future installation of additional cables (Apex Tray) . When laying multiple layers of cables in a tray, the distance between layers should also be 100–150 millimeters to ensure adequate cooling and prevent overheating (Kazkabel) .

Trench-Specific Considerations

In trenches, the spacing between power cables is influenced by voltage, heat dissipation, and mechanical protection. Typical guidelines include:

• Cables up to 10 kV: minimum distance 250 mm
• Cables 20–35 kV: minimum distance 500 mm
• Maximum six cables per trench; if more, separate trenches or cable blocks are recommended
• Passageways: maintain at least 0.8 meters between cable rows and building structures for maintenance access (Kazkabel) These distances ensure proper cooling, reduce fire risk, and allow safe access for repair or inspection. Shielding or partitions can be used to reduce spacing if necessary, especially in high-density installations (Kazkabel) .

Summary

• Parallel trays in trenches: ≥ 0.6 m
• Power vs signal trays: ≥ 0.5 m (≥ 0.3 m if shielded)
• Vertical clearance between trays: ≥ 150 mm
• Multiple cable layers: 100–150 mm
• Trench cable spacing: 250–500 mm depending on voltage, with ≥ 0.8 m passage for maintenance Following these spacing standards ensures safety, efficient heat dissipation, reduced EMI, and ease of maintenance in both tray and trench installations.