What type of cable is laid along the cable tray

The most commonly used cables in cable trays are Type TC (Tray Cable) for power and control, and ITC (Instrumentation Tray Cable) for instrumentation and control circuits.

Power and Control Cables

Type T

C (Tray Cable) is a factory-assembled cable consisting of two or more insulated conductors, with or without grounding conductors, under a non-metallic jacket. These cables are rated for 600 volts and are suitable for industrial power or control circuits. They are flame retardant and can be installed in cable trays, raceways, and outdoor locations if supported by a messenger wire.

T

C cables may also be used in Class 1, Division 2 hazardous locations and for direct burial if specified. For installations, TC cables must be secured at intervals not exceeding six feet, and TC-ER (Exposed Run) cables are permitted for short transitions between trays and equipment without continuous support.

Instrumentation and Control Cables

Type IT

C (Instrumentation Tray Cable) is designed for instrumentation and control circuits, typically operating at 150 volts or less and 5 amperes or less.

IT

C cables can be shielded or unshielded, with multiple single conductors or twisted pairs, and may include metal armor. They are available in sizes 22 AWG to 12 AWG and are intended for non-plenum and non-riser Class 2 and Class 3 circuits.

IT

C cables are often dual-rated as PLTC/ITC, allowing them to meet power-limiting circuit requirements while being installed in cable trays with proper mechanical support.

Installation Considerations

Cables in trays should be continuously supported using mechanical protection such as struts, angles, or channels. Spacing and fill limits must be respected to ensure proper heat dissipation and maintain ampacity. Ladder-type trays are preferred for power cables due to better ventilation and heat management, while solid or ventilated trays may be used for instrumentation cables where protection from electromagnetic interference is needed.

Environmental factors, such as exposure to moisture, chemicals, or outdoor conditions, influence the choice of cable jacket material and tray type.

Summary

In cable tray systems, Type TC cables are primarily used for power and control circuits, while ITC cables are used for instrumentation and control applications. Both types require proper support, spacing, and compliance with electrical codes to ensure safety, reliability, and optimal performance in industrial and commercial installations.