CMR Cable Tray

CMR cable refers to riser-rated communications cables designed for vertical installations in multi-story buildings, often routed through cable trays in riser shafts.What is CMR Cable?CMR stands for Communications Multipurpose Riser. It is a type of cable with a riser fire-resistance rating, defined under Article 800 of the National Electric Code (NEC) and tested according to UL 1666 and CSA FT4 standards . These cables are specifically designed to prevent fire from spreading between floors in multi-story buildings, making them suitable for vertical pathways such as riser shafts, floor-to-floor telecom routes, and multi-story low-voltage cabling systems .Construction and MaterialsCMR cables are typically made from polyvinyl chloride (PVC) with high-density polyethylene (PE) insulation or low-smoke PVC. This construction enhances flame-retardant performance compared to standard CM cables, ensuring safety in vertical installations . They are not intended for plenum spaces, which require CMP-rated cables with higher fire-resistance and low smoke emission.Use in Cable TraysA cable tray system supports, routes, and protects cables in a building's infrastructure. CMR cables are commonly installed in vertical cable trays within riser shafts to maintain organized and safe routing of communication and low-voltage cables . When installed in cable trays, CMR cables must be secured at intervals and comply with NEC guidelines to ensure proper fire safety and mechanical protection .Key ConsiderationsInstallation Environment: Use CMR cables for vertical riser shafts and floor-to-floor runs; avoid using them in plenum or air-handling spaces .Fire Safety: CMR cables limit flame propagation between floors, providing enhanced safety over general-purpose CM cables .Data Performance: The CMR rating does not define Ethernet speed or bandwidth; Cat5e, Cat6, or Cat6A CMR cables determine data performance .Compliance: Ensure cables are UL listed and meet NEC fire-resistance standards for riser applications . In summary, CMR cables in cable trays are essential for safely routing communication and low-voltage cables vertically in multi-story buildings, providing fire protection between floors while maintaining organized cable management.