Industry standards often recommend at least 300mm (12 inches) of spacing between power and control trays to minimize EMI. The spacing between trays, whether horizontal or vertical, depends on various factors like cable type, environment, and tray material. Proper installation can significantly reduce electromagnetic interference, prevent fire hazards, and improve overall efficiency. A minimum clearance of 9 in (22. 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. Below are the key principles to guide the layout of E&I cable trays, focusing on practical, safety, and efficiency aspects. This. Support spacing for cable trays must align with the manufacturer's instructions, as outlined in NEC 392. Generally, standard trays require supports every 6 to 10 feet, while heavy-duty, long-span trays can handle distances of up to 20 feet between supports. Protect Signal Integrity Why It Matters:.