The Ultimate Guide to Tray Cables: Types, Applications and Installation Standards

By Eileen Harvey 

When it comes to powering, automating and protecting facilitiesꟷfrom factories and petrochemical plants to data centers and high-risesꟷthe right cable makes all the difference. Among the various cable types, tray cables are a preferred solution for robust, adaptable, code-compliant wiring. Whether you’re an engineer, contractor, facilities manager or simply curious, this ultimate guide provides an in-depth understanding of tray cables, covering their types, standards, applications, installation practices and essential safety and compliance insights. 

What Are Tray Cables? 

Tray cables (TC) are multi-conductor cables designed and rated for installation in cable trays and raceways or supported by messenger wires. Unlike standard electrical cables, tray cables feature enhanced insulation and jacketing to withstand mechanical stress and exposure to oil, sunlight, moisture and a variety of chemicals. They are manufactured to carry power, control signals or data in commercial, industrial and utility environments. 

Tray cables simplify complex wiring needs by neatly and safely delivering power or signals over long distances, even in harsh or hazardous areas. Their design focuses on flexibility, durability and the ability to meet stringent industry standards for both safety and performance. 

Types of Tray Cables 

One size does not fit all in modern installations. There are several categories of tray cable, each tailored for specific environments and code requirements. 

1. TC – General Purpose Tray Cable 

TC (tray cable, per NEC Article 336, UL 1277) is a versatile cable suitable for use in cable trays, raceways and even direct burial (if specifically rated). TC can be used for power, lighting and control circuits in industrial and commercial locations. They’re available in many conductor counts, gauges and insulation compounds. 

2. TC-ER – Tray Cable with Exposed Run Rating 

TC-ER (tray cable, exposed run) is a step up in construction. It’s designed for use not only in trays but also in exposed runs of up to 6 feet (1.8 meters) between the tray and equipment, replacing the need for conduit in specified circumstances. This cable includes impact- and crush-resistant jacketing, meeting additional crush and impact standards verified by Underwriters Laboratories (UL). 

3. ITC – Instrumentation Tray Cable 

ITC (instrumentation tray cable, NEC Article 725) is intended for low energy (not exceeding 150 volts and 5 amps) control, signal and communication circuits. Often used for PLCs, DCS systems, transmitters and other instrumentation, ITC is characterized by smaller conductors and enhanced noise resistance. Some versions (ITC-ER) also permit short exposed runs. 

4. PLTC – Power Limited Tray Cable 

PLTC (power limited tray cable, NEC Article 725) is used in Class 2 and Class 3 power-limited circuits for alarm systems, intercoms, security and building automation. PLTC offers similar protections as TC but is suitable for jobs with lower voltage and limited power. 

5. MC Cable and Others 

While metal-clad (MC), armored, and AWM (appliance wiring material) cables are not tray cables per se, they are worth mentioning. Many share similar environments and requirements for mechanical resilience and safe routing in harsh industrial spaces. 

Key Standards: NEC, UL, and CSA 

Code compliance isn’t just bureaucracy—it’s a matter of life safety and long-term reliability. The world of tray cables is defined by three main standards: 

1. NEC (National Electrical Code) 

NEC Article 336 sets out the rules for the installation and use of tray cables in the U.S., including permitted locations, physical support, ampacity, exposure and more. 

NEC Article 725 covers ITC and PLTC, specifying where and how they can be installed, their limitations, and their conditions for exposed runs. 

2. UL (Underwriters Laboratories) 

UL 1277 quantifies tray cable construction, testing for insulation thickness, flame resistance, crush resistance and exposure to chemicals and sunlight. Cables should bear markings such as “UL TC-ER” or “UL ITC-ER” for easy compliance checks. 

3. CSA (Canadian Standards Association) 

Tray cables used in Canada must comply with CSA C22.2 No. 230 and other pertinent standards. Insist on CSA listings or markings for any North American cross-border projects. Compliance ensures not just legality, but uninterrupted insurance coverage, safety for personnel and minimized risk of costly shutdowns or equipment failures. 

Applications in Industrial and Commercial Settings 

Where will you find tray cables hard at work? Virtually everywhere mission-critical power or signals are needed. Common applications include: 

Industrial Automation 

Tray cables power motors, pumps, relays, PLCs, and sensors along production lines, chemical processes, pulp and paper mills and more. With their resilience against oil, solvents, vibration and abrasion, they’re ideal for harsh plant floor environments. 

Data Centers and Telecommunications 

Used in cable trays above or below “server farms,” tray cables link power distribution units (PDUs), backup generators and environmental controls. 

Commercial Buildings 

HVAC, lighting control, building automation, access control, fire alarms, intercoms and security cameras all run on reliable tray cables for uninterrupted power and data. 

Utilities and Renewable Energy 

Tray cable is found in solar farms, wind turbines and utility-scale battery storage—often with sunlight and direct-burial ratings for exterior use.