Cable tray is the preferred wiring method for industrial facilities, data centers, and large commercial buildings where routing dozens or hundreds of cables through individual conduits would be impractical and expensive. This is a description of how to select, install, and support these metal or plastic frames, on which electrical wires are installed. You should consider it as a series of instructions that make the buildings resistant to. en completely installed, without damage either to conductors or structural system use maintain spacing or to keep cables in place when the tray is ect the minimum bend ra-dius for cables as they exit the bottom of the cable tray. A rung spacing of 6 to 9 inches (150 to 230 mm) is preferable when. However, not all installations require cable trays, and it's essential to understand when and why you should use them. In this article, we'll discuss the main factors that determine whether or not you should use a cable tray for cables.