The types of cables, allowed in cable trays, and the wiring methods permitted in cable trays can be found in NEC Section 392. In general, tray rated cables are quality products that have been tested to withstand the rigors. This guide breaks down the six essential fire alarm cable types, focusing on their specific applications, compliance standards, and how they interact with cable tray containment systems to ensure building safety. FPL (Power-Limited General Purpose) 3 2. FPLR. en completely installed, without damage either to conductors or structural system use 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. Route Planning and Layout Principles Coordinate with Building Structure: Cable tray routing should align with architectural design, avoiding unnecessary.