This design statement provides a defensible, standards-based justification for using a 300 mm physical separation in lieu of a roof-mounted 120‐minute fire barrier. However, BS 7671, BS 8519, and BS 5839 collectively establish that. Separation isn't just an EMI precaution — it protects signaling, reduces rework, and ensures pathways meet inspection expectations across risers, plenums, and shared trays. Fire alarm circuits require dedicated pathways or 2‐inch minimum separation depending on circuit type per Article 760. Cable. Fire alarm cables, governed by codes like the National Electrical Code (NEC) Article 760, carry critical signals that alert occupants to danger and initiate emergency responses. Data cables, which fall under communications circuits in NEC Articles 725 or 800, transmit network data, voice, and video. Did you know the 2021 International Fire Code now requires 120 VAC single and multiple station smoke alarms to produce a 520 Hz low frequency audible tone? The definition of a fire alarm circuit is as follows: "The portion of the wiring system and connected equipment powered and controlled by the. The National Electrical Code (NEC), specifically Article 760, lays out the rigorous requirements for fire alarm system wiring, and deviating from these standards can have dire consequences. My goal here is to demystify these requirements, offering a deep dive into the intricacies of NFPA NEC 70.