Customization of long-span cable trays is supported

Long-span cable trays require careful customization of support spacing, tray strength, splice plate placement, and material selection to ensure structural integrity and reliable cable management. Support Span and Tray StrengthLong-span cable trays are typically supported at intervals of 14 to 20 feet, with 20 feet being the most common, while extra-long spans exceed 20 feet and can reach 20 to 40 feet for outdoor installations such as road crossings. The distance between supports directly affects tray strength, so the tray must be selected and designed to handle the specific span and expected load.

Matching tray length to support span helps control splice locations and maintain structural integrity.

Splice Plate Placement

Splice plates connect two tray sections and are critical in long-span installations. Only one splice plate should be placed between support spans to maintain strength and electrical grounding. Innovative designs, such as Eaton's KwikRail system, feature splice-retention grooves that simplify installation and secure the splice with minimal hardware.

Material and Environmental Considerations

Material selection depends on the installation environment. Common materials include steel, stainless steel, and aluminum, with various finishes to resist corrosion, extreme temperatures, and outdoor exposure. Aluminum is particularly valued for its corrosion resistance in atmospheric conditions, while steel may require galvanization or protective coatings.

For outdoor or harsh environments, extra-long spans reduce the number of expensive supports while maintaining durability.

Load Capacity and Cable Type

The load class of the tray defines its ability to support cables over a given span. Long-span trays must be rated for the expected weight of power, instrumentation, and data cables. Rung spacing, typically 6 to 9 inches, ensures proper support for small instrumentation and control cables.

Ventilated or solid-bottom trays may be selected based on heat dissipation and electromagnetic interference considerations.

Installation Best Practices

Align tray length with support span to minimize splice plates. Ensure proper grounding and bonding at splice locations. Use modular systems for flexibility in routing and future expansion.

Consider thermal expansion and contraction in outdoor or temperature-variable environments. Verify compliance with relevant standards such as NEC, IEC, or DIN EN 61537 depending on location.

Summary

Customization of long-span cable trays involves careful planning of support intervals, tray strength, splice placement, material selection, and load capacity. Proper design ensures safety, reliability, and cost efficiency, particularly in industrial, commercial, and outdoor applications where spans are extended and environmental conditions are challenging.