Load-bearing supports for vertical cable trays

Vertical cable trays should be supported at intervals that safely accommodate the cable dead weight, typically using wall-mounted brackets or suspended adapters, with fastening spacing generally not exceeding 1.2 meters and maximum cable loads around 20 kg/m.Key Standards and GuidelinesIEC 61537 defines the methodology for testing cable tray systems, including load-bearing capacity, but does not specify exact load values. It emphasizes Safe Working Load (SWL), which is the maximum load a tray can safely carry under normal conditions, tested with a uniformly distributed load (UDL). Deflection limits are set at 1/100 of the span longitudinally and 1/20 of the width laterally to determine SWL compliance . DIN 4102 Part 12 provides specifications for vertical cable ladders and trays, particularly for installations requiring circuit integrity maintenance. Vertical systems must prevent kinking or slipping of cables at edges, and continuous vertical ladders over 3.5 meters require effective lateral support or strain relief .Support Spacing and FasteningWall or structural mounting: Vertical cable ladders (STL, STM, STIC) can be fixed directly to walls or via internal/external wall connection angles (WWU 150/8 or WWI 80).Maximum fastening spacing: Typically ≤ 1.2 meters for vertical ladders .Cable dead weight: Maximum recommended is 20 kg/m for standard vertical ladders .Fasteners: Minimum M8 bolts for STL/STM, M10 for STIC; mushroom-head or flat round-head screws are used depending on the connection type .Suspended installations: If direct wall mounting is not feasible, vertical ladders can be suspended using adapters like the STBA vertical cable ladder fastening adapter .Material and ConstructionMaterials: Galvanized or stainless steel is standard for vertical trays and ladders.Rung spacing: Typically 300 mm between rungs, with C-profile rungs suitable for yoke clamps .Width: Standard widths range from 200 to 600 mm, depending on cable volume and installation requirements .Practical ConsiderationsEnsure continuous support for vertical runs to prevent cable sag or stress.Use tested system components together to maintain SWL and circuit integrity.For fire-rated installations, follow the E30, E60, or E90 classification for vertical cable ladders .Avoid using cable trays as walkways or for supporting personnel, as this can compromise safety and system integrity . By adhering to these standards and guidelines, vertical cable trays can safely support cables while maintaining compliance with mechanical and fire safety requirements.