How to handle cable trays in building corridors

Cable trays in building corridors provide organized, safe, and accessible pathways for electrical, data, and control cables, ensuring compliance with standards and facilitating maintenance.

Purpose and Benefits

Cable trays are used in corridors to support and route multiple cables efficiently, reducing clutter and minimizing the risk of mechanical damage or interference with other building systems . They allow for easy installation, inspection, and future expansion compared to conduit systems, as cables can enter or exit the tray at any point along its route . Properly designed trays also improve safety, reliability, and cost-effectiveness in commercial and industrial buildings .

Planning and Layout

When planning cable trays in corridors, consider the following:

• Route Selection: Trays should follow straight, logical paths with minimal bends to reduce stress on cables and simplify maintenance . Avoid routing near heat sources, vibrating equipment, or areas prone to moisture unless the tray is rated for such conditions .
• Clearance: Maintain sufficient space for cable pulling, inspection, and future maintenance. Horizontal and vertical runs should be coordinated with other services to prevent clashes .
• Support and Spacing: Supports must comply with manufacturer recommendations and standards such as IEC 61537, which defines spacing, load capacity, and mechanical strength . Typical support intervals are based on tray type, material, and cable load.
• Segregation: Power, control, and data cables should be separated according to IEC 60364 to prevent electromagnetic interference and ensure safety .

Installation Considerations

• Material Handling: Store trays horizontally on flat surfaces with timber supports to prevent damage and protect from moisture and sunlight .
• Fittings and Accessories: Use approved fittings, splice plates, and accessories to maintain structural integrity and continuity of the tray system .
• Load Capacity: Ensure trays are sized to accommodate current and future cable loads. For example, an 18-inch wide tray may have an allowable fill area of 21 square inches, equivalent to multiple conduits .
• Coordination: Installation zones should be clearly defined to avoid conflicts with other disciplines, and civil clearance must be obtained before starting MEP works .

Standards and Compliance

Adhering to IEC and NEC standards ensures safety, reliability, and legal compliance:

• IEC 61537: Design, bend radii, supports, and mechanical load testing for cable trays .
• IEC 60364: Cable segregation, voltage drop, and mechanical protection principles .
• NEC vs IEC: Be aware of differences in local codes and ensure the tray system meets both structural and electrical requirements .

Maintenance and Future Expansion

Cable trays in corridors allow for easy addition or removal of cables without major modifications. Proper planning ensures that future upgrades can be accommodated with minimal disruption, reducing long-term costs and downtime .

Key Takeaways

• Cable trays provide organized, safe, and flexible cable management in building corridors.
• Proper planning, support, and adherence to standards are essential for safety and reliability.
• They offer cost savings, easier maintenance, and scalability compared to conduit systems.