This guide covers the cable tray types and their appropriate applications, the fill rules for each configuration, ampacity derating requirements, separation of power and signal cables, and the decision criteria for choosing cable tray over conduit. Cable tray is the preferred wiring method for industrial facilities, data centers, and large commercial buildings where routing dozens or. Tray cables (TC, TC-ER, and similar types) are specially designed for use in cable tray systems, which support multiple runs of cable across industrial and commercial buildings. The information has been organized for use as a reference guide for both those unfamiliar and those experienced with cable tray. These systems, made from metal or plastic, are open structures designed to support electrical conductors, ensuring proper organization and safety. Here's what you need to know: Cable Types: Only use. association representing the major electrical equipment manufac-turers in the U. The Cable Tray ng standards, performance standards, test standards and application in this document have been tested extens ompetent professional en completely installed, without damage either to conductors or. This is a description of how to select, install, and support these metal or plastic frames, on which electrical wires are installed.