The core value of flame-retardant cables lies in their "difficulty to ignite," meaning they are difficult to ignite, or if ignited, they prevent the spread of flames and self-extinguish after the fire source has been removed. This primarily aims to reduce fire losses and prevent the spread of fire. The core value of fire-resistant cables lies in their "power preservation." In the event of a fire or cable burn, they can maintain normal power flow to the line for a certain period of time, buying valuable time for personnel evacuation and the activation of firefighting equipment.
How to Choose a Cable Scientifically? Three Key Dimensions
1. Risk Level of the Operating Environment
In areas with a high risk of fire spread (such as warehouses and chemical parks): Flame-retardant cables are preferred to reduce the probability of fire spread.
For life safety systems (such as emergency lighting and fire pumps): Fire-resistant cables are essential to ensure continued operation during disasters.
2. Safety Standard Requirements
Flame-retardant cables must comply with IEC 60332 (vertical flame test), equivalent to GB/T 18380 in China.
Fire-resistant cables must meet IEC 60331 (750°C continuous power supply test), equivalent to GB/T 19216 in China.
3. Balancing Costs and Long-Term Benefits
Flame-retardant cables are low-cost and suitable for large-scale installations.
Fire-resistant cables are expensive, but they can prevent catastrophic losses. For example, if a hospital operating room loses power due to a fire, the consequences far outweigh the cost of the cable.
The Design Logic of Flame-Retardant and Fire-Resistant Cables:
Flame-Retardant Cables:
Core Function: Suppresses flame spread and prevents fire from spreading along the cable.
How it works: By adding halogen or halogen-free flame retardants, they release inert gases or form a carbonized layer at high temperatures, cutting off the oxygen and heat required for combustion.
Typical Applications: Preventing fires from spreading in crowded places such as shopping malls, office buildings, and subway stations.
Fire-Resistant Cable:
Core Function: Maintains circuit integrity during a fire, providing continuous power supply for a specified period (typically 90-180 minutes).
How it works: Conductors are wrapped with high-temperature-resistant materials such as mica tape and ceramic silicone rubber. This ensures insulation performance even if the outer insulation layer burns out.
Typical Applications: Critical facilities such as fire protection systems, nuclear power plant control circuits, and power supplies for hospital emergency equipment.
Four Selection Taboos:
1. Not all cables labeled "flame-retardant" meet the standards. Third-party test reports (such as UL certification and CNAS laboratory reports) must be verified.
2. Avoid Ignoring Installation Environment Compatibility
For humid environments, choose halogen-free, low-smoke flame-retardant cables (to reduce corrosive gases).
For high-temperature workshops, confirm the long-term temperature rating of fire-resistant cables (e.g., 105°C or higher).
3. Avoid Mixed Installation Misconceptions
When flame-retardant and conventional cables are laid on the same cable tray, flames can pass through the conventional cables and ignite the entire system. Separating and isolating the cables is recommended.
4. Don't neglect maintenance and inspection.
Even if you choose high-performance cables, you still need to regularly check insulation resistance and connector oxidation to prevent performance degradation due to aging.
