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 article explains the principles, methods, and practical examples for calculating cable tray support quantity. Based on "Code for Acceptance of Construction Quality of Building Electrical Engineering" GB50303 and "Specification for Design of Steel Cable Tray Engineering" CECS31 Actual width of the. Although BS 7671 touches on the subject of cable supports, it does not detail specifically what these support distances should be. NEC Article 392 limits fill ratios based on cable type and arrangement — single-layer or stacked — to ensure adequate ventilation, maintain current-carrying capacity, and provide space. Calculate V-cut dimensions, bolt positions, slope length, and hanger spacing. SVG diagram for on-site marking. What is the Cable Tray Slope & Fabrication Calculator? The Cable Tray Slope & Fabrication Calculator is a field-ready tool for electrical construction workers who need to quickly calculate.