Cable tray support quantity can be calculated using a simple formula: Support Quantity = Total Length ÷ Support Spacing + 1 20 ÷ 2 + 1 = 11 supports In a typical project, a 20-meter cable tray with 2-meter spacing requires 11 supports. This calculator features an interactive interface with advanced visualizations. Save your cable tray sizing calculator results as branded PDF. A cable support system consists of cable support lengths and system components, such as cable support fittings, support elements, mounting elements and system acces-sories. Follow these simple steps: Define Tray Dimensions: Enter the width and depth of your planned cable tray (in mm or inches). For mixed cables, sum the areas of all individual cables.