A cable tray system is only as strong as its weakest specification. Undersized trays, excessive support spans or missing accessories lead to sagging, cable damage and safety risks. This guide covers the essentials of specifying and installing a reliable system.
1. Calculate the Cable Load
Start by listing all cables the tray will carry, including future capacity. Add the cable weight per metre and multiply by the tray length, then factor in a safety margin - typically 1.5x the working load. Remember that concentrated loads (like heavy power cables) reduce the allowable support span.
2. Determine Support Spans
Support span depends on tray width, material thickness and load. As a rule, wider trays and heavier loads require shorter spans. Manufacturer load-deflection tables (in accordance with standards such as NEMA VE-1 / IEC 61537) give the safe span for each configuration. Never exceed the published span for the load class.
3. Select the Right Accessories
- Connecting plates and screws: join tray sections securely and maintain continuity.
- Threaded rods and hanging frames: suspend trays from ceilings and structures.
- Bonding jumpers: maintain electrical continuity for earthing and safety.
- Bends, tees and reducers: handle changes in direction and size.
- Covers and partitions: protect cables and separate power from data.
4. Installation Best Practices
- Maintain correct earthing continuity across every joint.
- Separate power and data cables with partitions to avoid interference.
- Allow expansion gaps for long outdoor runs subject to temperature change.
- Support trays at the specified spacing and avoid point loading.
5. Sourcing Checklist
- Request load-deflection tables and material test reports.
- Confirm accessory availability for the full system.
- Check finish suitability for the installation environment.
- Ask about custom sizes, drawings and OEM/ODM support.
Tianjin Chuangshi Metal Products provides complete cable tray systems - trays, supports and accessories - with technical documentation and OEM/ODM support. Contact us for engineering drawings, samples and pricing.
