Support spacing depends on load and installation standards. Then apply the formula: Support Quantity = Length ÷ Spacing + 1 4. Adjust for Special ConditionsThe 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. The NEC has a requirement for ladder-type cable trays. Proper installation can significantly reduce electromagnetic interference, prevent fire hazards, and improve overall efficiency. screw tie) is used to external fastening element fasten support elements to supporting parts of the build-ing structure and, in. Support spacing: The maximum distance between supports for cable tray systems, which varies based on the tray type, load, and installation conditions. 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. us-trations without notice.
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