While it is technically possible to run power and low-voltage cables in the same tray under strict conditions, segregation or shielding is strongly recommended to ensure safety, compliance, and system reliability. While all data cable is ran within cable tray, about 20% or so of the fire alarm cable is sharing the same tray. The commissioning agents for the project have recently told us that this is against code, however in speaking with our fire alarm subcontractor they do not believe that to be the case -. Separation isn't just an EMI precaution — it protects signaling, reduces rework, and ensures pathways meet inspection expectations across risers, plenums, and shared trays. The reorganized NEC (NFPA 70) Chapter 7 limited energy articles, paired with TIA‑569‑E pathway requirements, define how these. Obviously, fire alarm cables are potentially life-saving equipment, carrying critical signals to the fire alarm control panel and allowing for timely warning of occupants in an emergency. EMI Data. (a) Nonpower-limited fire alarm circuits and Class 1 circuits may occupy the same enclosure, cable, or raceway provided all conductors are insulated for maximum voltage of any conductor within the enclosure, cable, or raceway. Technical Standards and Regulations NEC (National Electrical Code) Article 300.