The biggest difference between mineral insulated cables and refractory cables is that the cable structure is completely different, which determines the maximum temperature and time of fire prevention.
Introduction to mineral insulated cables
Mineral insulated cables are non-combustible, smokeless, non-toxic and fire-resistant. They are usually made of copper conductor, magnesia insulation material, copper or copper alloy sheath, and their performance conforms to the GB/T13033 related provisions of the national standard "mineral insulated cables and terminals with rated voltage up to and including 750V".Mineral insulated cables can be coated with organic materials as outer sheath, which should meet the requirements of halogen-free, low smoke and flame retardant.
Ii. Introduction to fire-resistant cables
Fireproof cable in the specified test conditions, the wire and cable is burned in the flame and in a certain period of time can still maintain the normal operation of the characteristics, that is, with the ability to maintain the integrity of the wire and cable, this and fire retardant cable is also different.Flame retardant cable in the specified test conditions, the wire and cable is burned, after the fire source is removed, the flame spread on the wire and cable only within a limited range and self-extinguishing characteristics, that is, with the ability to prevent or delay the occurrence or spread of flame wire and cable.There is another kind of cable is the combination of the two called halogen-free low-smoke flame-retardant and fire-resistant cable: material does not contain halogen, the corrosion of combustion products is low, combustion smoke and dust produced less and higher transmittance and has the ability to maintain the integrity of the line of fire-resistant wire and cable.
Iii. Differences in fireproof performance between mineral insulated cables and fire-resistant cables
1, mineral insulation cable fire performance requirements
Fireproof performance of mineral insulated cable
2, fire-resistant cable fire performance requirements
Fire resistance of cable
Obviously, mineral insulated cable temperature to 950 ℃, the highest keep 3 hours normal electricity;Fire-resistant cable is the highest temperature 750 ℃, maintain the normal electricity 90 minutes.
The mineral insulated cable is different from the refractory cable and can be laid together with the bridge
Iii. Laying of electric wires and cables
Provisions on the laying of electric wires and cables in the code for fire prevention design of civil buildings:
1. Flame-retardant cables and flame-retardant cables can be laid in the same cable bridge.
2. When laying the two power lines leading to the fire fighting equipment in the same metal groove box, separate measures shall be taken.
3. When the non-metallic material capacity of cables laid in the same cable bridge is greater than 14L/m, isolation measures shall be taken.
4. When laying fire fighting equipment lines in cable shafts, cable trenches and cable tunnels, cable supports can be used for laying, and metal conduits or metal groove boxes shall be used for protection when surface coating is applied on the ceiling or overhead floor;Wear metallic conduit or metallic chamfered box to should take besmear brushs fire prevention coating to wait for fire prevention protection measure.
5, fire equipment line dark application, should be used in the metal pipe or refractory hard plastic laying, and should be laid in the non-burning structure, and the protective layer thickness should not be less than 30mm.
6, mineral insulated cable (BTTZ, YTTW) can be used cable bracket, ladder frame or wall coating;
7. Isolated fire resistant cable ng-a (BTLY) shall be installed in A cable channel box.
8. Fire power distribution line shall be laid separately from other distribution lines;When laying in the same well trench, it is advisable to lay on both sides of the well trench.