Vertical shaft cable trays must comply with IEC 61537, NEMA VE 1, UL 568, and NEC/CEC standards, ensuring proper load support, material selection, and safe installation.

Overview

Vertical shaft cable trays are designed to support and route electrical, control, and communication cables in vertical runs, such as shafts, risers, or multi-story installations. They provide a safe, organized pathway for cables while maintaining mechanical integrity, fire safety, and accessibility for maintenance and future expansion .

Materials and Construction

Cable trays for vertical shafts are manufactured from steel, stainless steel, aluminum, or nonmetallic materials. Material selection depends on environmental conditions:

• Steel: Pre-galvanized or hot-dip galvanized for corrosion resistance .
• Stainless steel: AISI 316L or similar grades for high corrosion resistance, especially in chlorinated or humid environments .
• Aluminum: Lightweight, corrosion-resistant, suitable for indoor and outdoor applications .
• Nonmetallic (fiberglass): UL 568 compliant, resistant to chemical corrosion and electrical insulation requirements . Vertical shaft trays may be ladder, ventilated trough, solid bottom, or channel type, depending on cable type, heat dissipation needs, and structural requirements .

Design Specifications

Key design considerations for vertical shaft cable trays include:

• Load capacity: Must support the weight of cables and any additional mechanical loads. NEMA VE 1 provides span and load class designations .
• Rung spacing: Typically 150–230 mm (6–9 inches) to maintain cable support and prevent sagging .
• Bend radius: Minimum bend radius must be maintained to prevent cable damage at entry/exit points .
• Thermal expansion: Vertical trays must accommodate expansion/contraction due to temperature changes .
• Corrosion protection: Coatings or material selection must match environmental exposure, including humidity, chemicals, or outdoor conditions .

Standards and Compliance

Vertical shaft cable trays must adhere to multiple standards:

• IEC 61537: International standard for metal and nonmetallic cable tray systems, covering construction, testing, and performance .
• NEMA VE 1: Specifies manufacturing requirements for metal cable trays, including ladder, channel, and solid bottom types .
• UL 568: Covers performance and safety requirements for fiberglass cable trays .
• NEC (NFPA 70) and CEC (C22.1 Part 1): Provide installation rules, ampacity tables, and safety requirements for cable trays in the U.S. and Canada .
• NFPA 79 and NFPA 70E: Address industrial machinery and electrical safety, including protection against shock and arc flash hazards .

Installation Best Practices

• Ensure vertical alignment and secure anchoring to structural supports.
• Maintain minimum clearances from other services and walls.
• Use splice plates and support brackets at recommended intervals to maintain structural integrity .
• Consider fireproofing or covers for vertical shafts in high-risk areas.
• Verify compatibility with cable types, including power, control, and instrumentation cables .

Summary

Vertical shaft cable trays are critical for safe and organized vertical cable routing. Compliance with IEC 61537, NEMA VE 1, UL 568, and NEC/CEC standards ensures proper load support, material durability, and electrical safety. Proper design, material selection, and installation practices are essential to prevent mechanical failure, overheating, or fire hazards in commercial, industrial, and utility installations .