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. To determine the proper spacing, consult the manufacturer's load capacity chart, which accounts for the total weight of the. Although BS 7671 touches on the subject of cable supports, it does not detail specifically what these support distances should be. 8 (Other Mechanical Stresses (AJ)) in that document provides requirements for cable support. Clause 522-08-04 Where conductors or cables are not supported. The NEC requires that cable trays must be supported by members at an interval specified by the cable tray manufacturer, but not more than 5 feet for horizontal runs to support the weight of the cables and other loads. This spacing should generally be no less than 0. The primary reason for this separation is to minimize electromagnetic interference (EMI), which could. Ladder cable tray is available in widths of 6, 9, 12, 18, 24, 30, 36, 42 and 48 inches with rung spacings of 6, 9, 12 or 18 inches. Specifiers should be aware that some cable tray. The cable support lengths and fittings can basically be designed as cable trays, cable ladders or mesh cable trays, in which cables are routed. Fittings can, on the one hand, be used for horizontal or vertical changing of the routing direction or, on the other, to change the height or width of the.