Service Wire UL 1277 Dual Rated Tray Cable for 600V/1kV Applications



Understanding UL Dual Rated Tray Cable: What Are the Advantages?

Written February 2019 | Lee Perry, Engineering Manager at Service Wire Company

A Guide to UL Listings

Underwriters Laboratory (UL) is a third-party safety consulting and certification company that sets standards for an array of commercial, industrial, and consumer products. UL evaluates more than 70 different wire and cable product categories for safety, performance, quality, environmental impact, and regulatory compliance.

Wire and cable products with UL listing have been tested and approved by UL and meet the requirements of the National Electrical Code (NEC). A different file number is assigned for each approved construction and includes product specifications such as insulation material and voltage rating.

UL 1277: Power and Control Tray Cable

UL 1277, the standard for electrical power and control tray cable, was recently updated, allowing manufacturers with UL approved tray cable to market their product as 600V/1kV rated. To be dual rated, products must use a recognized 1kV rated conductor and pass a higher voltage AC Hipot test on the completed cable. This test requires each insulated conductor in finished cable to withstand a specified voltage range for one minute without breakdown. If a product passes the AC Hipot test, it is suitable for 1kV use.

Benefits of Dual Rated Tray Cable

Dual rated tray cable is a more robust product. It is a cost-effective alternative for applications that require a lower voltage cable but are at risk for potential voltage spikes. For example, 1kV rated tray cable can withstand greater electrical adversity; the impact of a disruptive event on the cable is smaller, and the recovery time is faster than in a less resilient system.

UL dual rated tray cable also offers flexibility in newer constructions. With new 575V and 690V motors appearing, standard XH tray can now be used because of its increased 1kV rating.

Additionally, dual rated tray cable has a smaller outside diameter than traditional 1kV tray cables, making it preferable in space-constrained installations.


UL 1277 was recently updated, allowing UL approved tray cable to be dual rated for 600V/1kV applications.

Advantages of Dual Rated Tray Cable:

  • More Robust Applications
  • Cost-Effective
  • Electrically Resilient
  • Smaller OD Than Traditional 1kV Tray Cables

Dual Rated Tray Cable Must:

  • Use UL 1kV Conductors
  • Pass Increased AC Hipot Test
  • Meet Updated UL 1277 Standard  



Service Wire’s tray cable has always been UL 1277 compliant and is now UL dual rated for 600V/1kV applications. Our products include:


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