2. Fire-resistant cables are mostly used as power supply circuits for emergency power supplies, requiring normal operation during fire. Due to the sharp rise of the ambient temperature during the fire, in order to ensure the transmission capacity of the line and reduce the pressure drop, the section of the fire-resistant cable should be at least one step for the circuit with a long supply line and strict limits on the allowable voltage drop.
3. In order to reduce the probability of failure of the cable joint in a fire accident, the number of joints should be minimized during installation to ensure that the line can work normally in a fire. If branch wiring is required, the joint should be fireproofed.
4. When fire-resistant cables are used in cable-dense cable tunnels, cable interlayers, or in flammable places such as oil pipes and oil depots, Class A fire-resistant cables should be used first. In addition to the above, and the number of cable configurations is small, a Class B fire resistant cable can be used.