Method for installing mesh cable trays on the ground

Wire mesh cable trays can be safely installed on ground-mounted supports if proper grounding, bonding, and NEC-compliant installation practices are followed.

Installation Overview

Ground-mounted mesh cable trays are widely used in industrial facilities, data centers, and commercial buildings due to their flexibility, open-grid design, and excellent airflow. These trays should be mounted on rigid supports such as steel or aluminum stanchions, ensuring stability and proper alignment. Supports must be spaced according to the tray manufacturer's recommendations, typically every 4 to 6 feet for standard loads, to prevent sagging and maintain mechanical integrity .

Cable Selection and Tray Fill

Only tray-rated cables (Type TC, MC, or other NEC-approved open-air conductors) should be installed in mesh trays. Power cables should not exceed 40% of the tray's cross-sectional area, while control or communication cables can occupy up to 50%. High-power and low-power cables must be separated to reduce electromagnetic interference (EMI), .

Grounding and Bonding

Proper grounding and bonding are critical for safety and NEC compliance. Metallic mesh trays can become energized under fault conditions, so a continuous electrical path is required:

• Electrical continuity: All tray sections and fittings must maintain conductive connections across the system .
• Bonding at splice points: Use bonding jumpers where mechanical connections alone do not ensure continuity .
• Connection to building ground: The tray system must be securely connected to the building's grounding electrode to provide a safe path for fault current .
• Equipment grounding conductor (EGC): While solid or ladder trays can sometimes serve as the EGC, wire mesh trays are not recommended as the sole EGC due to reduced current-carrying capability. Installing a separate ground wire along the tray is advised .
• Material considerations: Avoid bare copper in aluminum trays to prevent electrolytic corrosion; use insulated conductors with tin- or zinc-plated connectors at bonding points .

Mechanical and Thermal Considerations

The open-grid design of mesh trays allows natural heat dissipation, reducing cable temperature buildup, which is especially important in high-density installations supporting PoE devices, IP cameras, or automation controls . The modular nature of mesh trays simplifies future modifications, cable additions, and visual inspection of grounding connections.

Compliance and Safety

All installations must comply with NEC Article 392, including:

• Proper tray fill and separation of cable types .
• Maintaining at least 12 inches of vertical clearance above trays for access and maintenance .
• Ensuring trays remain accessible and are not installed in prohibited areas such as hoistways or enclosed spaces .
• Using firestop systems at penetrations where required . By following these guidelines, ground-mounted mesh cable trays provide a safe, flexible, and NEC-compliant solution for managing power, control, and data cabling in modern electrical infrastructure.