Vertical cable trays do not inherently require covers, but covers are recommended in certain situations for protection and environmental reasons.

NEC Compliance and Cable Requirements

According to the National Electrical Code (NEC) Article 392, cable trays, including vertical runs, do not require covers by default. The NEC mandates that cables installed in trays must be Tray Rated (Type TC) or metal-armored (Type MC) to ensure durability and safety in open-air environments, which allows the trays to remain uncovered while still protecting the conductors .

Situations Where Covers Are Recommended

While not mandatory, covers are beneficial in specific scenarios:

• High-traffic areas: Covers protect cables from falling tools or accidental impacts.
• Outdoor installations: Covers shield cables from direct sunlight, which can degrade plastic insulation over time.
• Dusty or corrosive environments: Covers help prevent debris accumulation and reduce exposure to corrosive agents.

Covers can be solid or ventilated, depending on the need for heat dissipation and cable support. Ladder trays, commonly used for power cables, typically remain uncovered because their open design provides excellent ventilation, while solid-bottom or ventilated trough trays may use covers to protect smaller or sensitive cables .

Installation Considerations for Vertical Trays

• Cable fastening: In vertical runs, cables should be secured to the tray's transverse members to prevent sagging or movement.
• Unsupported spans: When transitioning cables from vertical trays to equipment, unsupported spans should not exceed 6 feet; otherwise, additional supports are required .
• Environmental factors: Material selection (aluminum, steel, FRP) should match the environment to prevent corrosion or mechanical damage. Covers can enhance protection in harsh conditions .

Summary

Vertical cable trays do not require covers by code, but using them can improve physical protection, environmental resistance, and longevity of the cables. The decision to install covers should consider traffic, exposure, cable type, and environmental conditions, balancing protection with ventilation and heat dissipation needs .