Spacing Standards: Electrical (power) and instrumentation (signal/control) cable trays should maintain a minimum vertical and horizontal distance. 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. The spacing between trays, whether horizontal or vertical, depends on various factors like cable type, environment, and tray material. These Cable Trays are very versatile as they have slots or holes in them which provide good ventilation and help. Cable tray installation clearance requirements vary significantly between North American electrical codes.