Trough cable tray is generally used for moderate heat generating applications with short to intermediate support spans of 5 feet to 12 feet. Standard Widths: Sidewall Heights: Standard Lengths: Material Thickness by. 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. Note that wider rung spacings and wider cable tray widths decrease the overall strength of the cable tray. 5m, 3m, or 6m depending on regional standards. Below are common dimensions for different tray types: Note: Specific dimensions may vary by manufacturer and application.