When the cable tray is installed outdoors, the cable tray should be equipped with a protective cover at its upper layer or each layer. For proper installation, design, and maintenance, adherence to international standards is essential. One of the most recognized frameworks globally is the IEC standard for. 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 the cable tray cont d for instrumentation and control applications that require. Our Cable Tray Design Considerations Guide details key factors to consider when designing cable tray systems for industrial and commercial applications. This is a description of how to select, install, and support these metal or plastic frames, on which electrical wires are installed. Contractors are most likely to cut corners on materials. Cold Galvanizing (Electro-galvanizing): Looks shiny, like a mirror. It works in dry indoor environments, but once placed. Cable tray systems are structural components used to support insulated conductors and control, instrumentation, and communication cables.