Which type of cable should be used for indoor cable trays

The most commonly used cables in indoor cable trays are Type TC (Tray Cable) and ITC (Instrumentation Tray Cable), with options for exposed run (TC-ER) and power-limited applications (PLTC).Type TC (Tray Cable)Type TC cables are multi-conductor cables rated for 600 volts, designed for power, control, and lighting circuits in industrial and commercial settings (NEC Article 336) . They feature a durable non-metallic jacket that resists heat, moisture, oil, and sunlight, making them suitable for indoor cable trays. TC cables can be armored or unarmored and are available in various conductor counts and gauges. Common subtypes include:VNTC (Vinyl Nylon Tray Cable): Cost-effective, PVC outer jacket with nylon-coated inner conductors, suitable for general industrial use .XHHW (Cross-linked Polyethylene High Heat-resistant Water-resistant Tray Cable): Offers higher resistance to heat and moisture, ideal for more demanding environments .TC-ER (Exposed Run Tray Cable)TC-ER cables are designed for short exposed runs (up to 6 feet) between the tray and equipment without conduit. They include impact- and crush-resistant jacketing and meet UL standards for mechanical protection . TC-ER is useful when transitioning from the tray to devices or machinery in indoor installations.ITC (Instrumentation Tray Cable)ITC cables are intended for low-voltage control and instrumentation circuits (≤150 volts, ≤5 amps) such as PLCs, DCS systems, and transmitters (NEC Article 727) . They are available in shielded or unshielded constructions, often with twisted pairs to reduce electromagnetic interference. ITC cables may also have an ER rating for short exposed runs, but must be continuously supported .PLTC (Power-Limited Tray Cable)PLTC cables are low-voltage, power-limited cables suitable for control, fire alarm, and building automation systems. They are rated for 300 volts and are often dual-rated as PLTC/ITC for flexibility in indoor tray installations . PLTC cables are flame-retardant and may include shielding for EMI protection.Key Considerations for Indoor Cable Tray InstallationVoltage rating: Ensure the cable matches the circuit voltage (TC: 600V, ITC/PLTC: 300V).Mechanical protection: Use TC-ER or armored cables where exposed runs are required.Flame retardancy: Most tray cables are UL-listed and flame-retardant for indoor use.Support and spacing: Cables must be secured at intervals (typically every 6 feet for ER-rated cables) and supported to prevent sagging or damage . In summary, Type TC and ITC cables are the standard choices for indoor cable trays, with TC-ER and PLTC providing additional flexibility for exposed runs and low-voltage applications. Proper selection ensures compliance with NEC standards, mechanical durability, and safe operation in industrial and commercial environments.