Method for fabricating sliding hanger rods for cable trays

Sliding hanger rods for cable trays can be fabricated using corrosion-resistant threaded rods with unistrut or angle supports, allowing adjustable movement while meeting load and safety standards.

Materials and Standards

Sliding hanger rods are typically made from steel or stainless steel to ensure strength and corrosion resistance, with optional galvanization for additional protection . The design and installation should comply with BS EN 61537 for cable tray systems and BS 6946 for channel support systems . These standards ensure that the supports can safely carry the weight of the cable tray, cables, and imposed loads such as wind or maintenance activities.

Rod Sizing and Load Considerations

The diameter of the threaded rod is determined by the total load it must support. For example, a 1.5 m cable tray carrying 17 cables weighing 25.7 kg, plus the tray and support angles, may require M8 or larger rods depending on the yield strength of the material (e.g., 475 N/mm² for 8 mm rods) . The load per rod is calculated by dividing the total weight by the number of rods supporting the tray, ensuring each rod can safely carry its share.

Fabrication Method

1. Cutting and Threading: Cut rods to the required length and ensure threads are clean for nuts and washers.
2. Corrosion Protection: Apply galvanization or use stainless steel rods to prevent rust, especially in exposed or high-humidity environments .
3. Sliding Mechanism: To allow sliding, use unistrut channels or angle brackets with oversized holes or slots through which the rod passes. This permits lateral movement while maintaining vertical support .
4. Assembly: Attach the rod to the structural element (ceiling, beam, or precast panel) using anchor bolts or pre-cast holes. Mount the unistrut or angle brackets on the rod, then secure the cable tray with clamps or bolts, leaving enough clearance for sliding adjustments.
5. Safety and Access: Ensure fall protection and scaffolding are used during installation, especially for high-level trays, to prevent accidents .

Installation Tips

• Maintain uniform spacing of rods along the tray span (commonly 5 feet or 1.5 meters) to distribute load evenly .
• Use lock nuts or spring washers to prevent unintended movement while still allowing controlled sliding.
• Verify that the sliding mechanism does not compromise the tray's alignment or cable support integrity.
• Consider pre-fabricated hanger assemblies if available, as they reduce on-site labor and ensure compliance with standards . By following these guidelines, sliding hanger rods can be fabricated and installed to provide adjustable, safe, and durable support for cable tray systems in industrial or commercial installations.