In general, vertical spacing for cable trays should be 30 cm (12 in), measured from the bottom of the upper tray to the top of the lower tray., to facilitate installation of. The spacing between trays, whether horizontal or vertical, depends on various factors like cable type, environment, and tray material. The NEC has a requirement for ladder-type cable trays. The rungs cannot be more. Cable tray (or cable ladder) systems are a popular alternative to electrical conduit systems, as they have an outstanding record for dependable service, design flexibility and cost savings in commercial and industrial applications. 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. The spacing stated for horizontal runs may be applied also to runs at an angle of more than 30 Degrees from the vertical. For runs at an angle of 30 Degrees or less from the vertical, the vertical spacing is applicable.
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