Using Features
The rated voltage U0/U of the cable is 0.6/1KV. The rated voltage U0/U of the flame-retardant and fire-resistant control cable is 450/750V, and the rated voltage of the flame-retardant and fire-resistant wire and cable U0/U is 450. /750V and below.
The long-term allowable working temperature of PVC insulated cables does not exceed 70℃, and the long-term allowable working temperature of XLPE insulated cables does not exceed 90℃
The ambient temperature during installation should not be lower than 0°C.
The minimum bending radius when the cable is installed
The outer diameter (D) of the flame-retardant and fire-resistant wire is less than 25mm, the allowable bending radius of the cable should not be less than 4D, the outer diameter (D) is 25mm and above, and the allowable bending radius of the cable should not be less than 6D.
Flame-retardant and fire-resistant control cables: cables without armor layers should be no less than 6 times the outer diameter of the cables, cables with armored or copper tape shielding structures should be no less than 12 times the outer diameter of the cables.
The minimum bending radius of flame-retardant and fire-resistant power cables is shown in the table
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Project
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Single core cable
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Multi-core cable
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|
Unarmored
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Armored
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Unarmored
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Armored
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|
Minimum bending radius during installation
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20D
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15D
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15D
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12D
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D-Outer diameter of cable
Table 4 Nominal cross-section of neutral conductor of multi-core cable
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Nominal cross section of main insulated core conductor /min2
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Nominal cross section of neutral conductor /min2
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3+1, 3+2, 4+1 Cores
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4, 5 Cores
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|
4
|
2.5
|
4
|
|
6
|
4
|
6
|
|
10
|
6
|
10
|
|
16
|
10
|
16
|
|
25
|
16
|
25
|
|
35
|
16
|
35
|
|
50
|
25
|
50
|
|
70
|
35
|
70
|
|
95
|
50
|
95
|
|
120
|
70
|
120
|
|
150
|
70
|
150
|
|
185
|
95
|
185
|
|
240
|
120
|
240
|
|
300
|
150
|
300
|
|
400
|
185
|
400
|
Single-core cable conductive core is round, 16mm2 and above can be pressed tightly. For multi-core cables with a cross-section of 35mm2 and below, the core should be round, and those with a cross-section of 50mm2 and above should be fan-shaped, tile-shaped or semicircular. The fourth core (neutral core) in a four-core cable can be round or fan-shaped. The neutral wire of a five-core cable can be round or tile-shaped. Those with a diameter of 6mm2 and below are allowed to be composed of a single conductor, and those with a diameter of 10mm2 and above are composed of multiple single wires. The shaped conductor (sector, tile or semicircle) should be tightly pressed.
Table 5 Compact round core diameter
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Cross Section mm2
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Min.number of single wire
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Overalll diameter mm
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|
16
|
6
|
4.8
|
|
25
|
6
|
6
|
|
35
|
6
|
7
|
|
50
|
6
|
8.4
|
|
70
|
12
|
10
|
|
95
|
15
|
11.6
|
|
120
|
18
|
13
|
|
150
|
18
|
14.6
|
|
185
|
30
|
16.2
|
|
240
|
34
|
18.5
|
|
300
|
34
|
22.7
|
|
400
|
53
|
25.6
|
Power cable section range: see table 6
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Number of cores
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Section mm2
|
|
1
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1.5-800
|
|
2
|
1.5-185
|
|
3
|
1.5-300
|
|
4
|
1.5-300
|
|
3+1
|
2.5-300
|
|
5
|
1.5-240
|
|
3+2
|
2.5-240
|
|
4+1
|
2.5-240
|
Single-core steel ribbon cable is only suitable for DC system.
Insulated core identification: flame-retardant and fire-resistant power cables are separated according to the requirements of plastic insulated power cable insulation cores, and flame-retardant and fire-resistant control cables are separated according to the identification requirements of plastic insulated control cables. Fire-resistant wires and cables are color-separated according to the identification requirements of plastic insulated wires and cables.
Main performance
The fire resistance of the finished wire and cable is that it burns for 90 minutes under a flame of 750℃ and does not break down under the rated voltage. The test device for its fire resistance characteristics should comply with GB/T19216.11-2003 and IEC60331-11:1999, and the test procedures and requirements for fire resistance characteristics should comply with GB/T19216.21-2003 and IEC60331-21:1999
The flame-retardant properties of the finished flame-retardant and fire-resistant wire should be able to withstand 5 cycles of vertical burning test without transmitting flame. After the test, the continuous burning time of the sample should not exceed 1h. The finished cable should be subjected to a bundled cable burning test. After the test, the height of the scorched or affected part of the cable should not exceed 2.5m above the point of action of the flame.
Wire and cable should withstand -15℃ low temperature winding test or low temperature impact test. After the test, there should be no visible cracks on the surface of the sample.
70℃ finished wire insulation volume resistivity should be greater than 1*1010Ω•cm.
The finished flame-retardant and fire-resistant wire should be able to withstand the 2.5KV AC voltage test without breakdown in 5 minutes. The finished flame-retardant and fire-resistant control cable should be able to withstand the 3KV AC voltage test without breakdown in 5 minutes. The finished flame-retardant and fire-resistant power cable should be able to withstand the 3.5KV AC voltage test without breakdown within 5 minutes
Flame-retardant and fire-resistant wires and cables are made of highly flame-retardant polyvinyl chloride plastic, with an oxygen index greater than 30%
Except for the above characteristics, other performances are the same as those of the same kind of ordinary cables.
Key points for selecting fire-resistant cables
In the event of a fire, the wire core resistance increases due to the dramatic increase in ambient temperature. When the flame temperature is 800-1000℃, the conductor resistance increases by about 3-4 times. At this time, the system should still be guaranteed to work normally , Must check the voltage loss under this condition . Generally, it is enough to enlarge the selected wire and cable cross section under normal conditions (ie voltage deviation allowable value +5%~-5%) by one to two levels. Originally, when 50mm2 and below were selected, the first-level cross-section was enlarged, and when it was more than 70mm2, the second-level cross-section was enlarged.
The difference between high temperature resistant cables and fire resistant cables should be distinguished
Generally organic fire-resistant cables are not flame-retardant. If both fire-resistant and flame-retardant requirements are required, flame-retardant and fire-resistant cables or mineral insulated cables should be used.
Ordinary cables and fire-resistant cables are laid in the fire-resistant cable trough box, which may not meet the fire-resistant requirements.
