They must be plaster-sealed to the surrounding surface if the opening between the box and surface is more than 0. 4) Use intumescent wrap materials to firestop cable trays. Where cables pass through shafts, walls, slabs, or enter electrical panels or cabinets, openings shall be tightly sealed with firestopping materials in accordance with design requirements. Process flow: reserved openings → busway installation → distribution box positioning and installation →. maintain spacing or to keep cables in place when the tray is ect the minimum bend ra-dius for cables as they exit the bottom of the cable tray. 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. Cable tray covers not only offer physical protection to the cables but also enhance safety, improve system stability, and elevate the overall look of your installation. Adding a flange improves sealing in clean environments. The corrugation reinforces structure without adding much. Cables, cable bundles, conduits, bundles of conduits, empty pipes, cable trays and cable ladders may also pass through penetration seals in walls and floors and should be taken into consideration during all phases of design and application. The last part of our penetration seal series of articles. Improperly secured covers on outdoor cable trays can cause a serious hazard in harsh environment conditions such as wind, snow, and ice.