Construction Requirements for Mesh Cable Trays

Mesh cable trays must meet structural, electrical, and installation standards, including load capacity, grounding, material selection, and NEC/NEMA compliance.

Construction and Material Requirements

Mesh cable trays are typically made from high-strength steel wire, often with a powder-coated or galvanized finish to resist corrosion and environmental damage. Aluminum mesh trays are also used for their lightweight and corrosion-resistant properties. The tray design must provide adequate ventilation, support for cables, and maintain mechanical integrity under load.

Standard accessories include bends, tees, vertical elbows, splice plates, and covers to allow complex routing while maintaining structural strength.

Load and Span Considerations

Mesh trays are classified by load/span ratings, which define the maximum weight of cables they can support and the spacing of supports. Proper support spacing is critical to prevent sagging and mechanical stress on cables. Rung spacing is typically 6 to 9 inches (150–230 mm) for instrumentation and control applications.

Grounding and Bonding

Metal mesh trays must comply with NEC Article 392 for grounding and bonding. Key requirements include: Ensuring electrical continuity across all tray sections. Bonding at splice points to eliminate gaps in conductivity.

Using properly sized grounding conductors according to NEC tables. Connecting the tray system to the building grounding electrode system to provide an effective fault current path. Powder coatings or finishes that reduce conductivity must be accounted for to maintain bonding integrity.

Cable Types and Fill Limits

Only tray-rated cables (e.g., Type TC or MC) are permitted. Fill limits must be observed: power cables ≤ 40% of tray cross-section, control cables ≤ 50%. High-power and low-power cables should be separated to prevent electromagnetic interference (EMI).

Installation Guidelines

Maintain minimum vertical clearance (e.g., 12 inches) for access and maintenance. Avoid installation in hoistways or enclosed spaces; trays must remain accessible. Ensure secure attachment to supports and proper alignment to prevent cable damage.

Follow project specifications and local electrical codes in addition to NEC and NEMA standards.

Compliance Standards

Mesh cable trays must comply with: NEMA VE 1 for metal cable tray construction, load/span designations, and fittings.

CS

A C22. 2 #126. 1 for Canadian installations, harmonized with NEMA VE 1.

U

L 568 for nonmetallic systems if applicable.

NE

C Article 392 for installation, grounding, and fill limits.

Best Practices

Inspect trays for damage or coating defects before installation. Maintain continuous grounding paths throughout the tray run. Use appropriate accessories for bends, tees, and transitions to maintain mechanical and electrical integrity.

Plan for future cable expansion to avoid major modifications. By adhering to these requirements, mesh cable trays provide safe, organized, and code-compliant support for power, control, and data cables in industrial and commercial installations.