Cable trays are designed to carry tray-rated cables such as TC (Tray Cable), TC-ER (Tray Cable with Exposed Run), ITC (Instrumentation Tray Cable), power, control, Ethernet, and fiber optic cables.

Tray Cable (TC)

TC cables are multi-conductor cables with insulated conductors under a non-metallic jacket, rated for 600 volts, and suitable for power, control, and lighting circuits in industrial and commercial environments. They are UL listed and can be installed in cable trays, raceways, or outdoor locations supported by a messenger wire. TC cables are flame-retardant and may be used in Class 1, Division 2 hazardous locations when properly identified. TC cables are not generally permitted outside of trays except for short transitions up to six feet with proper support (TC-ER) or in outdoor messenger-supported runs .

Tray Cable with Exposed Run Rating (TC-ER)

TC-ER cables are designed for situations where the cable must leave the tray for short distances, up to six feet, without continuous support. They meet crush and impact requirements and are suitable for industrial environments where cables may be exposed to mechanical stress .

Instrumentation Tray Cable (ITC)

ITC cables are used for instrumentation and control signals. They can be shielded or unshielded, twisted pairs, and may include metal armor. These cables are designed to minimize electrical noise and are suitable for sensitive control and instrumentation applications .

Other Cables in Cable Trays

Cable trays can also carry:

• Power cables for industrial machinery and lighting systems, provided they are tray-rated .
• Control cables for HVAC, automation, and other control systems .
• Ethernet cables (CMR, CMP, or tray-rated) for network infrastructure, including PoE devices .
• Fiber optic cables for high-speed backbone connections between telecom rooms or data centers .

Key Considerations

• All cables must be UL listed and marked as cable tray rated.
• Cable trays have fill limits and separation requirements to prevent overheating and interference .
• Metallic trays require proper grounding and bonding, and firestop systems are needed at penetrations .
• The choice of cable depends on voltage, environment (indoor/outdoor, wet/dry), mechanical protection, and NEC compliance . In summary, the wires run through cable trays are primarily tray-rated cables such as TC, TC-ER, ITC, and other approved power, control, Ethernet, or fiber optic cables, all selected to meet NEC standards and environmental requirements.