This step‑by‑step approach helps you determine width, depth, support spacing, and allowable load with confidence. Plan 20–30% spare capacity for growth. Remember separation rules for. Eaton's B-Line series wide cable trays use stronger rungs to safely bear the loads published (only our 42 and 48-inch widths require load reductions). When supporting small diameter multi-conductor control and instrumentation cables, 6, 9, or 12-inch rung spacings should be specified. Quality Type. us-trations without notice. This calculator features an interactive interface with advanced visualizations. Big cables weigh more: Thicker cables with more conductors mean more material, so they are heavier. Armoured cables. Project Description: A 50-rack Tier III data center requires 300 CAT6 cables and 80 power cables (3-core, 6 mm²) routed over a 30-meter corridor using ladder trays. Tray Area Needed (Fill Factor = 50%): If using 75 mm height. Given in kilograms per lineal meter. An average load is 75 kg/m (165 lbs/ft). 150 mm (6"), 203 mm (8"), 300 mm (12"), 450 mm (18"), 600 mm (24"), 750 mm (30"), 900 mm (36"), 1067 mm (42"). 5"), 152 mm (6") 160 mm.