Precautions for using flame-retardant cables
With the continuous improvement of technology, flame retardancy has evolved from halogen flame retardancy in the past to low halogen and halogen-free flame retardancy. When developing and producing "flame-retardant and fire-resistant flexible cables for communication power supply", Tianjin Cable Factory Rubber and Plastic Cable Factory used halogen-free polymer materials with low smoke and halogen-free, high decomposition temperature, and good mechanical properties for the insulation and sheath of the cables. Since the cables do not contain halides and metal oxides, they will not produce harmful gases and a large amount of smoke during combustion, and there is no possibility of causing "secondary disasters". They also have good mechanical and electrical properties, meeting the requirements for cable use and changing the shortcomings of previous flame-retardant cables.
Use
1. Dense cables
When multiple cables are densely configured, the flame retardancy of the cables should be tested according to the "bundled wire and cable combustion test method", as well as the principles of cable configuration, required prevention of catastrophic accidents, and economic rationality, to meet the requirements of the appropriate category.
For the following places or circuits that need to maintain electricity for a certain period of time under the influence of external fire, exposed cables should be protected against fire or fire-resistant cables should be selected. Important circuits such as fire protection, alarm, emergency lighting, DC power supply for breaker operation, and maintenance power supply for emergency shutdown of generator sets; When computer monitoring, dual relay protection, security power supply and other dual circuits share the same channel but are not isolated from each other, one of the circuits is used.
2. Fire resistance protection of cables
When the number of cables is small, fireproof coating, tape wrapping can be applied to the cables or the cables can be threaded through fire-resistant pipes. When there are many cables in the same channel, they should be laid in fire-resistant trough boxes, and breathable types should be used for power cables. Semi enclosed types can be used in environments without flammable dust. When the cable protection section laid on the bridge is not long, fire-resistant packages can also be used.
Non combustible mineral insulated cables can be used in oil tank areas, important wooden public buildings, high-temperature locations, and other areas with high fire resistance requirements and acceptable installation and economic performance. When self contained oil filled cables are exposed in public corridors, passenger tunnels, bridges, and other areas that require fire prevention treatment, they can be buried in sand for installation. Cable trenches near high voltage current, voltage transformers, and other oil containing equipment should have their trench covers sealed.
3. Dense places
In cable intensive areas or enclosed channels with high safety requirements, fire automatic detection and alarm devices suitable for reliable environmental actions should be equipped. The oil supply system of the exposed oil filled cable should be equipped with automatic fire alarm and locking devices that can reflect the fuel injection status. Fire fighting facilities such as water spray extinguishing can be installed in places with high safety requirements, such as cable dense parts of underground public facilities, and the terminal settings of multi circuit oil filled cables.