Vertical cable trays in shafts should follow manufacturer guidelines and NEMA/NEC standards, typically allowing bends of 45° or 90° with proper support spacing and bend radius compliance.

General Guidelines

Vertical cable trays are used to route cables between floors or through shafts. The angle of installation and bends must comply with safety and electrical standards to prevent cable damage, maintain structural integrity, and ensure proper airflow and heat dissipation. Commonly, vertical shafts use straight runs with 45° or 90° bends where direction changes are required, following manufacturer specifications and NEMA/NECA recommendations .

NEMA and NEC Standards

• NEMA BI 50016-2024 provides guidance on cable tray design, installation, and support, emphasizing that vertical runs must be properly supported to prevent sagging or overstressing cables .
• NEC Article 392 outlines general cable tray installation requirements, including support intervals, allowable bends, and clearances in vertical shafts.
• Bend radius: Cables exiting or entering vertical trays must maintain the minimum bend radius specified by the cable manufacturer to avoid insulation damage .

Support and Spacing

• Vertical cable trays require intermediate supports at intervals recommended by the manufacturer, often every 4–6 feet for standard trays, depending on load and material .
• Rung spacing in vertical ladder-type trays is typically 6–9 inches (150–230 mm) to maintain cable stability and prevent sagging .

Material and Environmental Considerations

• Materials such as galvanized steel, stainless steel, or aluminum are selected based on environmental conditions, including corrosion resistance and mechanical strength .
• Covers or ventilated trays may be used to protect cables from dust, moisture, or electromagnetic interference in vertical shafts .

Practical Installation Tips

• Avoid sharp bends; use pre-fabricated elbows for vertical transitions.
• Ensure alignment with horizontal trays to maintain smooth cable routing.
• Verify compliance with local electrical codes and manufacturer installation manuals, as deviations can void warranties or violate safety regulations . By following these guidelines, vertical shaft cable tray installations can maintain safety, code compliance, and long-term reliability. Proper planning of angles, support spacing, and bend radius is essential for both performance and regulatory adherence.