Electrical Cable Trays in Building Corridors

Cable trays in corridors provide a safe, organized, and code-compliant method to support and route electrical, control, and communication cables.

Purpose and Function

Cable trays serve as structural pathways for electrical and communication cables, offering mechanical support, organization, and accessibility for maintenance or future expansion. They are commonly installed overhead, along walls, or under raised floors in corridors, electrical rooms, and industrial facilities, ensuring cables are protected from physical damage and environmental hazards while maintaining compliance with electrical codes and standards.

Types of Cable Trays

Ladder Tray: Features side rails connected by rungs, ideal for power and large control cables due to excellent ventilation and easy cable tie-down.

Ventilated Trough/

Perforated Tray: Provides continuous support for smaller cables while allowing airflow to prevent overheating.

Solid-

Bottom Tray: Offers maximum protection for sensitive or EMI-prone cables, suitable for control and instrumentation wiring.

Wire Mesh/

Basket Tray: Lightweight, flexible, and ideal for light-duty control, communication, and data cables.

Materials and Finishes

Steel (pre-galvanized or hot-dip galvanized): Cost-effective, durable for indoor and many outdoor applications. Aluminum: Lightweight, corrosion-resistant, suitable for industrial and offshore environments. Stainless Steel: High corrosion resistance for chemical, marine, or hygienic environments.

FR

P (Fiber Reinforced Plastic): Non-metallic, corrosion-resistant, and non-conductive for highly corrosive or specialized environments.

Installation Guidelines

Planning and Layout: Review approved shop drawings, mark tray routes, and coordinate with other services to avoid clashes. Maintain horizontal and vertical runs with adequate clearance for cable pulling and maintenance. Support and Spacing: Use wall brackets, trapeze hangers, or cantilever supports.

Typical support spacing is based on tray type, load, and manufacturer recommendations, often around 1. 2 meters for ladder trays to prevent sagging. Cable Fill and Segregation: Calculate maximum fill per NEC Article 392 to prevent overheating.

Separate power, control, instrumentation, and communication cables using dividers or separate trays to reduce electromagnetic interference. Grounding and Bonding: Metallic trays should be bonded and may serve as equipment grounding conductors if permitted. Use bonding jumpers and connect to the building grounding system at regular intervals.

Fire Protection: Provide firestopping at wall and floor penetrations, use fire-resistant cables where required, and consider tray covers to protect against debris or liquids. Maintenance and Inspection: Perform periodic inspections for corrosion, mechanical damage, loose supports, or overloaded sections. Ensure cables are properly secured and identification labels remain legible.

Best Practices

Use ladder trays for heavy power cables and ventilated or solid-bottom trays for control or data cables. Ensure trays are accessible and do not obstruct walkways or emergency exits. Provide expansion joints for long runs to accommodate thermal expansion.

Treat cut edges with protective coatings to prevent corrosion. Maintain proper documentation and inspection records for compliance and future maintenance. By following these guidelines, cable trays in corridors can provide a reliable, safe, and organized system for electrical and communication cabling, supporting both current and future infrastructure needs.