Fire resistant cables, also known as circuit integrity cables, are designed to maintain electrical functionality during a fire for a specified period. Unlike standard cables that may fail quickly under flame exposure, these specialized cables ensure power and signals continue to critical safety systems. In 2025, with increasing urbanization and stringent building codes, the purpose of fire resistant cables is more vital than ever for protecting lives and enabling safe evacuation.

1. Introduction

In a fire, ordinary cables can lose insulation integrity within minutes, cutting power to emergency lighting, alarms, sprinklers, and ventilation. Fire resistant cables are engineered to withstand direct flame, heat, and mechanical shock, preserving circuit operation long enough for evacuation and firefighting—typically 30 to 180 minutes depending on rating.

2. Primary Purpose: Circuit Integrity

The core purpose is to guarantee continuous operation of essential services during a fire. This includes powering fire alarms, emergency lighting, smoke extraction fans, fire pumps, and lift controls. By maintaining functionality, these cables buy critical time for occupants to escape and for responders to act, significantly reducing casualties and damage.

3. How Fire Resistant Cables Work

Fire resistant cables incorporate mica tape wrapped directly around conductors—this glass-mica composite forms a ceramic-like barrier when heated, retaining insulation even at 950°C+. Combined with silicone rubber or ceramic-forming compounds, they resist flame penetration. Many also feature LSZH (low smoke zero halogen) sheaths to minimize toxic emissions.

4. Fire Resistant vs. Flame Retardant Cables

5. Key Standards and Tests

• IEC 60331: Tests circuit integrity under flame at 750-950°C.
• BS 6387 CWZ: Rigorous protocol—flame (C), water spray (W), mechanical shock (Z).
• EN 50200: PH classification (30/60/90/120 minutes).
• BS 8519: Categories for power/control in fire safety systems.

Common ratings: PH30 (30 min), PH120 (120 min).

6. Critical Applications

• Emergency lighting and exit signs.
• Fire alarm and detection systems.
• Smoke ventilation and pressurization fans.
• Firefighting lifts and sprinklers.
• Public buildings, hospitals, tunnels, high-rises, and data centers.

7. Selection Considerations in 2025

Choose based on required duration (PH rating), environment (water/mechanical shock), and regulations. Increasingly, combined fire resistant + LSZH cables are specified for enhanced safety. Verify third-party certification and compatibility with supports/clips rated for fire conditions.

8. Final Thoughts

The purpose of a fire resistant cable extends beyond mere wiring—it is a lifeline during emergencies. By ensuring critical systems remain powered when seconds count, these cables save lives and limit damage. In 2025's safety-focused construction landscape, specifying fire resistant cables is not just compliance—it's responsibility.

For fire resistant cables meeting IEC 60331, BS 6387, and other global standards, contact Henan Province Jianyun Cable Co., Ltd. for reliable solutions and expert guidance.