Install fire barriers within the tray to isolate different fire zones. When cable trays pass through walls or floors, seal openings using fire-rated penetration sealing materials. At slab penetrations, provide 20–30 mm of firestopping and install a fire-support plate at the top. For large. Cable tray installation must comply with specific technical standards to ensure electrical safety, system reliability, and long-term maintainability. Use fire barriers, covers, and dividers to contain flame spread, especially at crossings, risers, and penetrations. The following pages address the 2014 National Electrical Code® requirements for cable tray systems as well as design solutions from practical experience.