Our free calculator helps you determine the correct tray size based on NEC and IEC standards. Follow these simple steps: Define Tray Dimensions: Enter the width and depth of your planned cable tray (in mm or inches). Select Fill. Metosu's TRC (perforated) and TRU (non-perforated) trays ship in 10 widths (100–900 mm), 4 depths (50–150 mm), and 2 standard lengths (2,400 and 3,000 mm), all in 1. Load rating: 420 kg/span, NEMA Class 8B at 2,400 mm span. The calculation sums the cross-sectional areas of all cables including their outer sheaths and checks against the. Selecting the appropriate cable tray dimensions and size is essential for many kinds of reasons: The size of the cable tray has to be suitable on account of the kind of cables and the number of cables that it will carry. Overcrowding cables or using a small tray can cause electrical interference. Why is accurate cable tray sizing important for preventing overheating, ensuring efficiency, and allowing future expansion? What key factors influence cable tray sizing, including cable type, load capacity, environment, and industry standards? What common mistakes should be avoided in cable tray. 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.