Fire-Resistant Cable Knowledge-Qingdao Yilai Cable Co., Ltd.,

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Fire-Resistant Cable Knowledge

Release date:

2021-12-07

China's national standard GB12666.6 (equivalent to IEC 331) classifies fire-resistance tests into two levels: Level A and Level B. For Level A, the flame temperature ranges from 950°C to 1000°C, with a continuous fire exposure time of 90 minutes; for Level B, the flame temperature is between 750°C and 800°C, also with a continuous fire exposure time of 90 minutes. Throughout the entire test, the specimen must withstand the product’s specified rated voltage.

Fire-resistant cables are designed to maintain safe operation for a specified period when exposed to flames. According to China's national standard GB12666.6 (equivalent to IEC 331), the fire-resistance test is categorized into two levels: Level A and Level B. For Level A, the flame temperature ranges from 950°C to 1000°C, with a continuous fire exposure duration of 90 minutes; for Level B, the flame temperature is between 750°C and 800°C, also with a 90-minute fire exposure period. Throughout the entire test, the cable sample must withstand the product’s rated voltage as specified. These cables are widely used in high-rise buildings, subways, underground shopping malls, large-scale power stations, and critical industrial and mining enterprises—places where fire safety and emergency rescue operations are paramount. For instance, they serve as the power and control lines for essential emergency equipment, such as firefighting devices and emergency evacuation lighting systems.

1. Rated operating voltage: U/U (V series: 600/1000V, K series: 450/750V, B series: 450/750V).

2. Maximum Long-Term Operating Temperature of the Cable

(1) Flame-retardant polyvinyl fluoride insulation and sheath: available in 70°C and 105°C versions; cross-linked polyethylene insulation: 90°C;

(2) Fluoroplastic insulation and jacket: available in 220°C and 260°C versions; fluoroplastic insulation with a flame-retardant PFA jacket rated for 105°C and 125°C.

(3) Low-halogen, low-smoke, flame-retardant PVC insulation and sheath: 70°C; halogen-free, low-smoke, flame-retardant polyolefin insulation and sheath: available in two grades—90°C and 125°C.

3. Minimum ambient temperature:

(1) Flame-retardant polyvinyl chloride insulated and sheathed: Fixed installation—40°C; Non-fixed installation—15°C;

(2) Fluoroplastic insulation and sheath: Fixed installation –60°C; Non-fixed installation –20°C;

4. The safe laying temperature for cables should not be lower than 0°C.

5. Fire Resistance Properties:

Complies with IEC 331 standards, complies with GB 12666.6 standards

Flame temperature: 750℃ Flame temperature: 950℃–1000℃ Flame temperature: 750℃–800℃

Burning time: 3 hrs Burning time: 90 mins Burning time: 90 mins

Cooling time: 21 hours Additional voltage: Rated voltage Additional voltage: Rated voltage

Additional voltage, rated voltage Additional current, 3A Additional current, 3A

Additional current: 3A Class A Class B

6. Recommended minimum bending radius: For non-armored, braided-shielded cables, it should be no less than 6 times the cable's outer diameter;

The steel tape-armored cable shall have a minimum bending radius of 12 times the cable's outer diameter;

Cables with fluoroplastic insulation and jacketing materials should be at least 8 times the cable's outer diameter.