Yes, cables can be laid in cable trays, provided they are tray-rated and installed according to NEC standards and industry best practices.

Types of Cables Allowed

Cable trays are designed to support power cables, control cables, communication cables, and optical fiber cables. Common types include TC, PLTC, ITC, MC, MI, and communication cables, as well as fire alarm and emergency system cables . Only approved tray-rated cables should be used to ensure safety and compliance with the National Electrical Code (NEC) Article 392 .

Installation Guidelines

• Tray Fill Limits: Power cables should not exceed 40% of the tray's cross-sectional area, while control cables can fill up to 50% .
• Separation: High-power and low-power cables must be separated to prevent electromagnetic interference (EMI). A minimum separation of two inches is generally recommended, but specific requirements depend on the cable type and circuit .
• Bend Radius and Support: Maintain the minimum bend radius for cables exiting the tray and use proper supports to prevent mechanical stress . Ladder-type trays are commonly used for heavy or multi-conductor cables.
• Grounding and Bonding: Metallic trays must be properly grounded to ensure electrical safety .
• Fire Safety: Firestop systems are required at penetrations, and in plenum spaces, fire-rated ties should be used instead of standard plastic ties .

Environmental Considerations

• Material Selection: Choose tray materials such as aluminum, steel, or FRP based on environmental conditions, load requirements, and corrosion resistance .
• Outdoor Installations: Use sunlight-resistant cables and expansion splice plates to accommodate thermal expansion .

Limitations

Cable trays are not suitable for hoistways, enclosed spaces, or areas subject to severe physical damage. They must remain accessible for maintenance and should not be permanently enclosed . Mechanical utility piping or tubing containing water, air, or other non-electrical services cannot be installed in trays with electrical cables .

Best Practices

• Pre-plan cable routing to avoid overfilling and mechanical stress .
• Segregate power, control, and communication cables to minimize interference .
• Follow NEC and manufacturer guidelines for tray installation, grounding, and cable support . By adhering to these standards and practices, cable trays provide a safe, organized, and efficient method for routing multiple types of electrical and communication cables in industrial, commercial, and data center environments.