For fire-resistant cable, many people may think that fire-resistant cable will not burn, but will fire-resistant cable really not burn?
The fire-resistant internal cable can still maintain the normal operation of the line for a period of time under the condition of combustion, that is to say, in case of fire, the fire-resistant cable will not burn at once, and it can still maintain the normal power supply for a period of time.
This characteristic determines that fire-resistant cable plays an important role in modern urban and industrial buildings, because in case of fire, the power supply circuit of control, monitoring, guidance and alarm system must be maintained in normal operation.
Workers should pay attention to the following problems when installing fire-resistant cables:
1. When fire-resistant cables are used in cable tunnels with dense cables, cable interlayers, or in inflammable places such as near oil pipes and oil depots, class A fire-resistant cables should be selected first.Remove these conditions, and the number of cable configuration is small, should be selected B fire-resistant cable.
2. Fire-resistant cables are mostly used as the power supply circuit of emergency power supply, and are required to work normally in case of fire.Due to the sharp rise of ambient temperature during fire, in order to ensure the transmission capacity of the line and reduce the voltage drop, the section of fire-resistant cable should be enlarged by at least one step for the circuit with a long power supply line and a strict limit on the allowable voltage drop.
3. Fire-resistant cables shall not be used as high temperature resistant cables.
4. In order to reduce the failure probability of cable joints in fire accidents, the number of joints should be reduced as far as possible in installation to ensure the line can work normally in fire.If branch wiring is required, the joints should be fireproof.