TECHNOLOGY & SERVICE

Difference between fire resistant cable and flame retardant cable

2023-03


1、 Fire-resistant cable
On the basis of improving the manufacturing process of the refractory layer and increasing the refractory layer, a Class A refractory cable has been developed, which can withstand combustion for at least 90 minutes in a flame of 950 ℃ to 1000 ℃ and rated voltage without the cable being broken down (i.e., the 3A fuse does not blow).
2、 Flame retardant cable
Flame retardant cable is a type of fire resistant cable with superior neutral performance, which is made of copper core, copper sheath, and magnesium oxide insulation material, referred to as MI (mineral insulated cables) cable.
This cable is completely composed of inorganic substances to form a fire resistant layer, while the fire resistant layer of ordinary fire resistant cables is composed of inorganic substances and ordinary organic substances. Therefore, the fire resistance performance of MI cables is better than that of ordinary fire resistant cables and does not generate corrosive gases due to combustion and decomposition.
MI cables have good fire resistance characteristics and can work under high temperatures of 250 ℃ for a long time. They also have the characteristics of explosion-proof, strong corrosion resistance, large current carrying capacity, radiation resistance, high mechanical strength, small size, light weight, long service life, and smokeless.
However, due to the high price, complex process, and great construction difficulty, this type of cable with good fire resistance can be used in places with high fire resistance requirements and acceptable economy, such as oil irrigation areas, important wooden structure public buildings, and high-temperature places.
Note: Fire-resistant cables can maintain normal power supply for a period of time in the event of a fire, while flame-retardant cables do not have this feature
3、 Problems needing attention in design and application
1. When fire-resistant cables are used in densely packed cable tunnels, cable interlayer, or in flammable locations such as oil pipes, oil depots, etc., Class A fire-resistant cables should be selected first. In addition to the above, and when the number of cable configurations is small, Class B fire-resistant cables can be used.
2. Fire-resistant cables are mostly used as power supply circuits for emergency power supplies, requiring normal operation in the event of a fire. Due to the sharp rise in ambient temperature during a fire, in order to ensure the transmission capacity of the line and reduce voltage drop, for circuits with long power supply lines and strictly limited allowable voltage drop, the cross-section of the fire-resistant cable should be enlarged by at least one level.
3. Fire resistant cables cannot be used as high temperature resistant cables.
4. In order to reduce the probability of cable connector failure in fire accidents, the number of connectors should be minimized during installation to ensure that the line can work normally in a fire. If branch wiring is required, the joints should be properly fireproof.