Fire-fighting and non-fire-fighting cables in the same cable tray

Fire-fighting (fire-resistant) cables should generally be segregated from non-fire-fighting cables to ensure circuit integrity during a fire, though co-location may be allowed under strict standards and protective measures.

Key Considerations

Fire-fighting cables are designed to maintain electrical functionality during a fire, ensuring critical systems like emergency lighting, fire alarms, and smoke extraction continue to operate . They often include mica tape or other fire-resistant materials to protect the conductor and insulation at high temperatures . In contrast, non-fire-fighting cables (standard power or communication cables) may be flame-retardant but are not guaranteed to operate during a fire .

Risks of Co-Locating

Placing fire-fighting and non-fire-fighting cables in the same tray can introduce risks:

• Heat Transfer: Non-fire-fighting cables may contribute to fire spread or heat accumulation, potentially compromising the fire-resistant cable's performance .
• Circuit Integrity: Fire-resistant cables may fail to maintain operation if exposed to excessive heat from adjacent non-fire-rated cables.
• Regulatory Compliance: Many standards, including IEC 60331, BS 6387, and EN 60332, recommend separation to ensure fire safety objectives are met .

Best Practices

1. Segregation: Where possible, install fire-fighting cables in separate trays or compartments to maintain circuit integrity during a fire .
2. Physical Barriers: If co-location is unavoidable, use fire-rated barriers, partitions, or trays with fireproof separation to reduce heat transfer and prevent flame propagation .
3. Cable Selection: Ensure fire-fighting cables meet the required fire-resistance rating (e.g., FE180, FE90) and are suitable for the intended application, including emergency systems .
4. Compliance Check: Verify local building codes and fire safety regulations, as some jurisdictions strictly prohibit mixing fire-resistant and standard cables in the same tray.
5. Routing Considerations: Avoid running non-fire-fighting cables above or alongside fire-fighting cables in vertical risers or critical escape routes to minimize risk .

Conclusion

While technically possible under controlled conditions, co-locating fire-fighting and non-fire-fighting cables in the same tray is generally discouraged. Segregation or protective measures are recommended to ensure that fire-fighting cables can perform their critical function during a fire, maintaining safety and compliance with international standards .