If tray tilts at any location, provide 1-1/2 inch pipe in compression over hanger rods, a bar stiffener at hanger rods, or other manufacturer recommended anti-tilt method of mounting tray. The cable tray vendors should be installed firmly and horizontally and vertically. Here's a deeper look at what it addresses: 1. IEC 61537 specifies load testing methods to. When installing the cable tray horizontally, its direct plate connection should not be placed at the midpoint of the span or on the support point. A rung spacing of 6 to 9 inches (150 to 230 mm) is preferable when the cable tray cont d for instrumentation and control applications that require. Standard Aluminum Ladder • The rungs provide a convenient anchor for tying down cables in vertical runs or where the positions of the cables must be maintained in horizontal runs. • Cables may exit or enter through the top or the bottom of the tray.