A profile, fire-resistant cable performance

Ships, oil platform, large power stations, large enterprises and high-rise building and other special environmental requirements for work in the fire can still maintain a live communication power cable, for the use of fire alarm, lighting, communications.

IEC331), such as China's national standard GB12666.6 (will fire test points A, B two levels, A grade flame temperature of 950 ~ 1000 ℃, the duration for fire, 90 min, class B flame temperature of 750 ~ 800 ℃, for fire duration 90 min, during the whole test, the sample should be under the rated voltage value of the product.

Fire-resistance cable - MI cable could satisfy the requirement of such as cable appeared on the market, with inorganic insulation (magnesium), bronze protection layer of the cable; Another kind of the polymer insulation and heat-resistant mica, fire-resistant cable with flame retardant plastic sheath. The MI cable fireproof performance good, safe and reliable, but the price is higher.

Mineral insulated cable in a foreign country to carry out the earlier, the Swiss engineer patented in 1896, 1936, the main industrial national law, England, Italy, Canada, the United States and Sue sequential production and rapid development. Our country also in mass production, the beginning of the 20th century into the 21st century national fire prevention design specification and extensive use in the country.

Second, the fire-resistant cable structure

Fire-resistant cable structure is usually: silicon rubber insulation - alkali-free glass fiber woven - fire resistant paint glass mat layer - wire shielding - flame retardant rubber sheath; Cable conductive core consists of a copper wire or complex stranded wire.

Fire-resistant cable generally can meet the cable fire resistance to accord with GB12666.6 IEC331 regulations stipulated as follows:

The flame temperature of 750 ℃ temperature 950 ℃ to 1000 ℃ flame temperature of 750 ℃ to 800 ℃

Burning time 3 h burning time of 90 min the burning time of 90 min

Cooling time 21 h additional voltage rated voltage additional voltage rated voltage

Additional voltage rated voltage additional current 3 a additional current 3 a

Additional current 3 A class A class B

Practice has proved that silicon rubber insulation refractory cable was difficult to remain in the complex fire insulation. The UK on the basis of IEC331 increased, therefore, part of the test cable vibrations in the fire and water spray is still under the condition of safe electricity, BS - 6387 on the condition of fire test of a variety of adjustments, and give some signs, such as:

Combustion under 950 ℃ for 30 min for C type;

Combustion under 950 ℃ for 15 min with heat and mechanical vibration of Z;

650 ℃ for 30 min heat and water spray combustion test under the condition of W;

Britain in 1980 for conducting wire core is designed on the north sea oil into compound mica/belt and 3-20 insulating glass, can fire test under 1000 ℃, 3 h.

Three, mica and characteristics

Mica is a kind of materials, ores due to its excellent dielectric properties, thermal stability, has been one of the best materials for electrical insulating mica. Mica natural mica (Muscovite and phlogopite), synthetic mica, the chemical composition of white mica for aluminum and potassium silicate, minerals, and its essence is flake structure has good heat resistance and processing properties, electrical properties changed little under 500 ℃, and dominant in the market.

Adoption of mica tape insulating refractory cables and other than no mica fire-resistant cable structure can greatly improve the cable overall performance. Characterized by the prescribed time, the environment in the process of combustion, combustion or after a certain period of time, still can continue to normal power supply. Cable as early as the inorganic insulation and metal sheath, but the process is complex, hard to bend, cable and cable once water, insulation performance greatly reduced or even short circuit. Outside the conductor wire winding and a layer of glass mica tape, PVC insulated and sheathed fire-resistant cable, to overcome the hard structure fire-resistance cable this is insufficient, but there are other deficiencies, such as mica is easy to fall off.

New halogen free flame retardant fire-resistant cable can conform to the requirements of the modern safety, when the fire alarm, releasing amount of smoke and toxicity was low, the affected people can clearly find the fire source and mountain, and its flame retardant composition can effectively play a role of flame retardant, which does not make cable channel of flame spread.

Four, halogen free flame retardant fire-resistant cable fire retardant properties and mechanical properties

Want to ask

standards

Refractory, 750 ℃, satisfy 3 h

IEC60331

800 ℃ into cable fire test

IEC60332-3

From burning gas acid

IEC60754-2

Burning light transmittance of smoke concentration of flue gas release

IEC61034

950 ℃ fire test meet 3 h

BS6387:1994

650 ℃ water spray test meet 3 h

BS6387:1994

950 ℃ mechanical test meet 15 min

BS6387:1994

Five, fire-resistant cable sheath plastic technical requirements

Fire-resistance cable sheath plastic is low smoke zero halogen material, has the very good fireproof performance, the flame can generate dense porous carbon layer, has good heat insulation performance. Cable structure with thermal radiation layer, don't need mica, can pass the GB19216, IEC60331, BS6387 (CWZ) wire and cable fire test of 90 ℃ heat resistance level sheath plastic, the oxygen index, tensile strength, elongation at break, heat aging and thermal deformation, conductivity, etc as to meet the requirements of typical values.

Six, fire-resistant cable manufacturing process

Mineral insulated cable technology mainly include precast magnesia porcelain column method, magnesium hydroxide filling method, three kinds of continuous welding argon arc welding method. The precast magnesia porcelain column method is a common manufacturing methods. Prefabricated magnesia porcelain column method production process has two kinds: hot press molding in, dry pressing molding in.

Seven, fire-resistant cable common type

model

The name of the

note

NA - YJV/NB - YJV

Cross-linked polyethylene insulated PVC sheathed fire-resistant power cable (B) A class

Can be equipped on the refractory has the requirement for laying indoors, in tunnel and pipeline.

NA - YJV22 / NB - YJV22

Cross-linked polyethylene insulation tape armored PVC sheathed (B) A kind of fire-resistant power cable

Suitable for refractory is buried when asked, not suitable for the pipe laying.

WDNA - YJY/WDNB - YJY

Cross-linked polyethylene insulation polyolefin sheath (B) A low smoke zero halogen fire-resistant power cable

Can be equipped on the low smoke and fire have requirements for laying indoors, in tunnel and pipeline.

WDNA - YJY23 / WDNB - YJY23

Cross-linked polyethylene insulating sheath steel tape armoured polyolefin (B) A kind of low smoke zero halogen fire-resistant power cable

Suitable for low smoke zero halogen and refractory is buried when asked, not suitable for the pipe laying.

Voltage grade - V series: 600/1000 V, K series: 450/750 V, B series: 450/750 V