Fire protection wires must use fire-rated cables and approved junction or distribution boxes to ensure circuit integrity during a fire.

Fire-Rated Cable Selection

For fire protection circuits, use specialized fire-rated cables designed to maintain electrical function under fire conditions. Common types include FPL (Fire Power Limited), FPLR (Riser), and FPLP (Plenum), each suited for specific building environments and fire risks . These cables ensure that critical systems like alarms, emergency lighting, and smoke extraction remain operational during a fire .

Distribution Box and Junction Box Requirements

Fire protection wires should be connected to certified fire-resistant distribution or junction boxes, such as OBO FireBoxes or Spelsberg WKE boxes. These boxes are tested to maintain electrical function for defined periods (E30, E60, E90), providing reliable power to safety systems during emergencies . The boxes must be installed according to manufacturer instructions, ensuring proper strain relief, torsion protection, and secure cable entry using compatible glands .

Installation Guidelines

• Segregation and marking: Fire protection circuits should be clearly marked and separated from non-critical circuits to prevent accidental disconnection or interference .
• Overcurrent protection: Use dedicated breakers for fire protection circuits, labeled as "FIRE ALARM CIRCUIT" or equivalent, accessible only to qualified personnel .
• Mechanical protection: Ensure cables are routed through conduits or protected pathways to prevent damage and maintain integrity during fire .
• Compliance: Follow local building codes, BS 7671 standards (Chapter 42 for fire protection), and relevant NFPA or IEC regulations to ensure legal and safety compliance .

Practical Considerations

• Verify that all components, including cables, glands, and boxes, have certificates of suitability or approvals such as DIN 4102 Part 12 or VDE certifications .
• Ensure that the system maintains power for the required duration (e.g., 30, 60, or 90 minutes) to support evacuation and firefighting operations .
• Regular inspection and testing are essential to confirm that the fire protection wiring and distribution boxes remain functional and compliant. By using fire-rated cables, certified distribution boxes, and following proper installation practices, fire protection circuits connected to a distribution box can reliably maintain operation during a fire, ensuring safety and regulatory compliance.