In the mission-critical environment of a modern data center, every component must meet the highest standards of safety, reliability, and efficiency. This extends beyond servers and switches to the very cables that power and control the facility. For low-voltage power distribution, backup systems, and control circuits, UL1277 TC-ER (Tray Cable, Exposed Run) has emerged as the industry-preferred cabling solution, especially for projects adhering to North American codes and high-safety standards.
TC-ER cable is uniquely engineered for exposed installation within cable trays, offering a blend of high current capacity, superior flame resistance, and installation flexibility that is perfectly suited to the dynamic and dense infrastructure of data centers.
Core Positioning: The Ideal Cable for Data Center Support Infrastructure
TC-ER cables are specifically designed for the alternating current (AC) power and control side of data center operations. They are not used for structured data cabling (like Ethernet), but rather for the essential circuits that keep the facility running. Their primary advantages in a data center context are:
- Exposed-Run Compliance: Can be installed directly in cable trays/ladder rack without mandatory conduit, saving significant time, material cost, and improving airflow management.
- High Flame Resistance: Meets stringent flame-retardant standards (like VW-1), helping to prevent fire spread in cable trays—a critical concern in tightly packed vertical and horizontal pathways.
- Flexibility & Adaptability: Easily routes between power distribution units (PDUs), Uninterruptible Power Supplies (UPS), generators, and HVAC units, supporting both backbone and branch circuit applications.
Key Application Circuits for TC-ER in Data Centers
The versatility of TC-ER cable makes it suitable for several critical pathways within a data center’s support infrastructure.
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Application Circuit
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Primary Use Case
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Why TC-ER is Ideal
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UPS Output & Battery Bank Connections
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High-current feeds from the UPS system to switchgear and between battery strings.
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Offers high ampacity and thermal stability (90°C rating) for efficient power transfer, handling high inrush currents reliably.
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Generator to ATS/Main Switchgear
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Emergency power feeds from backup generators.
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Resists oil, moisture, and environmental factors; its flame-retardant properties are crucial for life safety circuits.
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Low-Voltage Power Distribution
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Branch circuits from Power Distribution Units (PDUs) to server cabinet racks.
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Allows for exposed tray routing directly to equipment, simplifying installation and changes in hot/cold aisle configurations.
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HVAC, Fire & Building Management Systems
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Power and control for CRAC/CRAH units, chillers, pumps, fire alarm panels, and BMS/EMS sensors.
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Withstands the mechanical stress and temperature variations near cooling equipment; some types (like XHHW-2) offer excellent chemical resistance.
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Critical Lighting & Security
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Emergency lighting, access control, and other essential low-voltage control loops.
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Provides a reliable, code-compliant wiring solution for systems that must remain operational during an event.
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Installation & Routing Best Practices for Data Centers
Proper installation is key to leveraging TC-ER’s benefits while ensuring safety and performance.
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Exposed Run Compliance: Per NEC Articles 336 and 392 and UL1277, TC-ER cables are expressly listed for use in cable tray without additional conduit. This directly increases pathway utilization and accelerates deployment compared to traditional conduit-and-wire methods.
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Cable Tray Management:
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- Segregation: Power cables (TC-ER) and data/communication cables should be placed in separate trays or with approved partitions. A minimum separation of 300mm (approx. 12 inches) is a common best practice to mitigate Electromagnetic Interference (EMI).
- Bend Radius: Adhere to the cable’s minimum bend radius during installation to prevent insulation damage.
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Environmental Considerations:
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- Ambient Temperature: While data halls are typically controlled at 20-25°C (68-77°F), providing a generous de-rating buffer for the cable’s 90°C rating, localized hot spots near UPS bays or transformer rooms must be assessed. Cable ampacity must be de-rated based on the actual ambient temperature in the specific tray section.
- Future-Proofing: Design tray fill and cable sizing with future capacity growth in mind to avoid overheating.
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Safety & Grounding:
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- Equipment Grounding Conductor (EGC): TC-ER cables must include an insulated ground conductor to meet NEC grounding requirements, ensuring a safe path for fault currents.
- Support & Secure: Cables must be properly secured within the tray to prevent stress on termination points, especially in vertical runs. Consider thermal expansion/contraction in long, straight runs.
Conclusion: The Reliable Backbone for Critical Power
For data center engineers and designers, specifying UL1277 TC-ER cable is a strategic decision that enhances electrical infrastructure reliability, safety, and flexibility. It simplifies complex power routing for UPS systems, generators, and PDUs while meeting the rigorous fire safety and electrical codes mandated for critical facilities.
By choosing the right TC-ER cable type—such as XHHW-2 TC-ER for superior temperature and environmental resistance or THHN TC-ER for controlled indoor environments—you ensure your data center’s support infrastructure is built for both performance and longevity.
Power your critical infrastructure with confidence. At JZD Cable, we supply high-quality TC-ER cables that meet UL, NEC, and ICEA standards, engineered to support the relentless demands of modern data centers. Contact us to find the optimal cable solution for your next project.
