Parallel cable tray laying ensures multiple cables in the same phase carry balanced currents while preventing overheating and insulation damage.

Overview of Parallel Cable Tray Laying

Parallel cable tray laying involves installing multiple cables for the same phase side by side within a cable tray system. This method is commonly used in high-power electrical systems where a single cable cannot carry the required current. Proper arrangement is critical to avoid imbalanced current distribution, which can lead to overheating, deformation of insulation, and reduced cable lifespan (Prysmian) .

Key Methods and Considerations

1. Cable Arrangement and Phase Sequencing

• Cables must be arranged to minimize magnetic field interactions and impedance differences.
• For single-core cables, a single-row sequence is recommended, following the correct phase order to ensure equal current distribution.
• The arrangement should comply with IEC 60364-5-52 and other international standards to prevent overheating and maintain system efficiency . 2. Cable Tray Selection
• Choose trays with sufficient rigidity and strength to support the weight of multiple cables.
• Ventilated or ladder-type trays are preferred for high-current applications to allow heat dissipation and prevent thermal buildup .
• Ensure the tray deflection does not exceed 1/200 of the span (or 1/150 for spans ≥ 6000 mm) after cable installation . 3. Spacing and Thermal Management
• Maintain adequate spacing between parallel cables to reduce mutual heating.
• Avoid installing trays directly under or above thermal pipelines or corrosive pipelines; if unavoidable, maintain a minimum distance of 500–1000 mm and use protective insulation or corrosion-resistant covers .
• Proper spacing ensures uniform current flow and prevents localized overheating. 4. Installation Precautions
• Coordinate tray installation with civil structures and other services to ensure safe operation and maintenance access.
• Use appropriate support elements, fasteners, and fittings to secure trays and maintain alignment .
• Inspect for potential contact corrosion when using dissimilar metals in humid or contaminated environments . 5. Compliance and Standards
• Follow national and international standards such as GB 50217-2018, GB 50168-2018, IEC 60364-5-52, and Electrical High Current Facilities Regulations for parallel cable installations .
• Ensure that the installation allows for future maintenance, expansion, and safe operation.

Summary

Parallel cable tray laying requires careful planning of cable arrangement, phase sequencing, tray selection, spacing, and thermal management. Correct implementation ensures balanced current distribution, prevents overheating, and extends cable lifespan, while complying with relevant electrical standards and safety regulations. Proper installation also facilitates maintenance and reduces the risk of operational failures.