Introduction to PLTC Tray Cables
Industrial control systems rely on a vast network of cables connecting PLCs (Programmable Logic Controllers), sensors, actuators, and field devices across manufacturing facilities. PLTC tray cables, classified under NEC (National Electrical Code) Article 725 as Power Limited Tray Cables, are the standard cable type for these control and signal circuits in North American industrial installations, designed specifically for installation in cable trays without additional conduit.
From automotive assembly lines and food processing plants to water treatment facilities and material handling systems, PLTC cables provide the reliable signal transmission that keeps automated production running. TEBAOFLEX manufactures a comprehensive range of PLTC tray cables compliant with NEC Article 725, UL 13, and CSA C22.2 standards for industrial control applications.
What Are PLTC Tray Cables?
PLTC (Power Limited Tray Cable) is a cable classification defined by NEC Article 725 for Class 2 and Class 3 power-limited circuits. The designation covers cables rated up to 600V for installation in cable trays, raceways, or supported by messenger wire in industrial environments. Key characteristics include:
- Voltage rating: 300V (Class 2) or 600V (Class 3 / PLTC)
- Conductor: Solid or stranded copper, typically 16-14 AWG (1.31-2.08 mm²)
- Pair and triad construction: Individual twisted pairs or triads for noise rejection in instrumentation circuits
- Shielding: Optional individual pair/triad shields and overall shield for EMI protection
- Outer sheath: PVC, LSZH, or rubber compound rated for tray installation and flame retardancy per UL 1685
- Approvals: UL 13 (PLTC), CSA C22.2 No. 239, and FT4/IEEE 1202 flame ratings for Canadian installations
PLTC cables are designed for free installation in cable trays without conduit, reducing installation cost and complexity compared to individual conduited runs. Explore our PLTC cable product range for available configurations.
NEC Article 725 Classifications
Understanding the NEC classification system is essential for proper cable selection in North American installations:
- Class 1 circuits: Power-limited circuits up to 600V and 5A, supplied by a regulated power source. Cables must meet PLTC requirements.
- Class 2 circuits: Power, voltage, and current limited for safety (typically 30V, 100W max). Used for signaling, control, and data circuits. Cables may be PLTC, CL2, or CL3.
- Class 3 circuits: Similar to Class 2 but with higher voltage/current limits (typically 100V). Requires CL3 or PLTC rated cables.
- PLTC: The tray cable designation applies to both Class 2 and Class 3 circuits installed in cable trays in industrial commercial and agricultural buildings.
PLTC cables may be installed in the same cable tray as power cables (with separation) and do not require conduit when installed in listed trays. This provides significant cost savings in large industrial facilities with extensive control wiring.
Construction and Design
PLTC tray cables are engineered for the demands of industrial cable tray installations:
Conductors and Pairing
Solid (18-16 AWG) or stranded (16-10 AWG) bare or tinned copper conductors with PVC or XLPE insulation. For instrumentation applications, conductors are arranged as individually twisted pairs (2-wire) or triads (3-wire) with specific twist pitches for noise rejection. Standard pair counts range from 1 to 24 pairs.
Shielding Options
- Unshielded: For general-purpose control circuits in low EMI environments
- Overall shield only: Aluminum/polyester tape with drain wire for moderate EMI environments
- Individual pair shield + overall: Maximum noise rejection for instrumentation and analog signal circuits in industrial environments
Sheath Materials
- PVC: Standard industrial tray cable sheath, flame retardant per UL 1685
- LSZH: Low smoke zero halogen for enclosed areas and tunnel installations
- PUR: Polyurethane for flexing applications and high-abrasion environments
- Rubber (NEOP/NR/SBR): For outdoor, wet, and harsh environment installations
Technical Specifications
| Parameter | PLTC Standard | PLTC Shielded |
|---|---|---|
| Standard | NEC Art. 725 / UL 13 | NEC Art. 725 / UL 13 |
| Voltage Rating | 300V / 600V | 300V / 600V |
| Conductor | Cu, 18-10 AWG | Cu, 18-14 AWG |
| Pair Configuration | 1-24 pairs | 1-24 shielded pairs |
| Insulation | PVC / XLPE | XLPE / PE |
| Individual Shield | None | Al/poly tape + drain |
| Overall Shield | None | Al/poly tape + TC braid |
| Outer Sheath | PVC / LSZH / PUR | PVC / LSZH |
| Flame Test | UL 1685 / IEEE 1202 | UL 1685 / IEEE 1202 |
| Max Temperature | 75°C / 90°C | 90°C |
Industrial Applications
PLTC tray cables serve diverse industrial control and automation systems:
PLC I/O Networks
Input/output modules connecting to field sensors (proximity switches, photoelectric sensors, limit switches) and actuators (solenoid valves, motor starters) use multi-conductor PLTC cables for cost-effective tray-installed wiring. See industrial application cases.
Process Instrumentation
For 4-20 mA analog signals from temperature, pressure, and flow instruments, individually shielded pair PLTC cables prevent noise interference in plant environments with high-power machinery and VFDs.
Building Automation
HVAC controls, lighting management, security systems, and energy monitoring networks use PLTC cables for their flexibility in tray routing and compliance with building codes for low-voltage control circuits.
Material Handling
Conveyor systems, automated storage and retrieval systems (ASRS), and packaging equipment use flexible PLTC cables with PUR sheaths for drag chain and flexing applications. See our cable types selection guide for flexing applications.
Selection Guide for PLTC Cables
- Determine circuit classification: Class 2 (30V max) or Class 3 (100V max) per NEC Article 725
- Select conductor count: Based on signal count plus 20% spare capacity; pair/triad arrangement for instrumentation
- Choose conductor size: 18 AWG for short runs, 16 AWG for general use, 14 AWG for long runs or higher current
- Select shielding level: Unshielded for digital I/O, overall shield for analog, individual pair shield + overall for instrumentation
- Choose sheath material: PVC for indoor, LSZH for enclosed areas, PUR for flexing, rubber for outdoor/wet
- Verify flame rating: UL 1685 (US) or IEEE 1202 / FT4 (Canada) for tray installation
- Check approvals: Confirm UL 13 listing and CSA C22.2 certification — view our certifications
- Request support: For complex control system designs, contact TEBAOFLEX
Why Choose TEBAOFLEX PLTC Cables
TEBAOFLEX manufactures PLTC tray cables for industrial automation and control applications worldwide:
- Multi-pair and multi-conductor configurations from 1 to 24 pairs (18-10 AWG)
- Individual pair shield + overall braid screen options for EMI-sensitive instrumentation
- PVC, LSZH, PUR, and rubber sheath options for all industrial environments
- UL 13 listed and CSA C22.2 certified for North American installations
- Custom designs with armor for mechanical protection and integrated signal types
Our custom manufacturing services support industrial automation projects from design to installation. For UL/CSA listings and technical consultation, contact TEBAOFLEX or browse our product catalog.
Request a Quote
Need PLTC tray cables for your industrial control system? Our engineering team will respond within 24 hours with detailed specifications, UL/CSA listings, and pricing. Submit your PLTC cable inquiry to TEBAOFLEX.
