Cable Specification Table for Horizontal Fixed Cables in Cable Trays

Horizontal fixed cables in cable trays should be selected based on conductor size, ampacity, tray type, and compliance with NEC, UL, and CSA standards. Key Considerations for Horizontal Fixed Cables1.

Conductor Size and Ampacity

Use the American Wire Gauge (AWG) system to determine conductor size. For example, 18 AWG carries ~14–16 amps, while 4 AWG carries ~85–95 amps. Ampacity depends on load, run length, and installation method.

Horizontal tray installations allow better air circulation, often permitting smaller gauge sizes compared to conduit. Voltage drop should be considered for long runs to ensure proper voltage at connected equipment. 2.

Cable Tray Types and Installation

Common tray types include ladder, ventilated, solid bottom, and channel trays. Rung spacing of 6–9 inches (150–230 mm) is recommended for horizontal runs to support cables and maintain proper bend radius. Horizontal fixed cables should be installed without damage, maintaining spacing to prevent overheating and mechanical stress.

Covers may be used for protection against dust, moisture, or electromagnetic interference. 3.

Environmental and Material Considerations

Select cables with UV resistance, flame retardancy, and temperature tolerance suitable for indoor or outdoor environments. Tray materials include steel (pre-galvanized or hot-dip galvanized), aluminum, and stainless steel, chosen based on corrosion resistance and mechanical strength. 4.

Compliance and Standards

Follow NE

C Article 392 for cable tray installation, spacing, and support. Ensure cables meet UL, CSA, and local code requirements for safety and performance. Verify that the selected cable type is suitable for the intended environment and load conditions.

Example Specification Table (Horizontal Fixed Cables in Tray)AWG SizeMax Ampacity (A)Typical Tray TypeJacket TypeNotes1814–16Ladder/ChannelTC, TC-ERSmall control or instrumentation cables1420–25Ladder/VentilatedTC, TC-ERGeneral power/control wiring1035–40Ladder/VentilatedTC, TC-ERMedium power distribution655–65Ladder/SolidTC, TC-ERHigh-power circuits485–95Ladder/SolidTC, TC-ERLarge motors or heavy loadsNotes: TC = Tray Cable, TC-ER = Tray Cable, Exposed RunAmpacity values assume horizontal tray installation with adequate spacing and ventilation. Adjust conductor size for long runs or high ambient temperatures to prevent voltage drop and overheating.

By following these guidelines, you can ensure safe, efficient, and code-compliant installation of horizontal fixed cables in cable trays.