The following is a brief talk about the moisture-proof treatment methods and purchase points of low-voltage power cables
The following is a brief talkLV power cableMoisture-proof treatment methods and purchase points
LV power cableMoisture-proof treatment method
If the thin part of the low-voltage power cable sheath does not meet the requirements, the cable sheath will be damaged before reaching the normal external destructive force. Because the magnesium oxide crystal powder used as an insulator in the low-voltage power cable is a kind of high moisture absorption rate Material, once the outer sheath is slightly damaged during cable transportation and laying, the magnesium oxide crystal powder will be affected by moisture and the resistance will be greatly reduced. In addition, when making the middle end joint of the cable, the cable should be cut off, which will also cause the magnesium oxide crystal powder to be damp.
There are usually two situations:
1. Cable damping end dehumidification method
InLV power cableAt the end, the range of moisture intrusion is generally 300-400mm, but if the end of the cable is not temporarily sealed and exposed to the air for a long time, moisture can invade about 1m. At this time, the wet end of the cable can be tilted upward, and the cable can be gently baked with a gasoline burner from about 1m away from the end of the cable, so that the moisture in the magnesium oxide of the cable is gradually discharged from the inside to the outside. If the insulation resistance measured after baking, continue to bake the other end of the cable in the same way until the insulation resistance is acceptable.
2. Discover and repairLV power cableDamaged copper sheath
When the copper sheath of the middle part of the cable is broken during construction, the repair method is:LV power cableAfter dehumidification by flat fire, the insulation resistance value of the insulation layer at both ends does not rise or changes little, which can be judged as the fault of the middle part. The full length of the cable can be baked by low fire, and the high resistance gear of the multimeter can be used to search. If the pointer reading changes greatly when baking a certain part, the fault point can be determined here, then the power supply system can be cut off, baked by low fire for dehumidification, check whether the insulation value is qualified, and connected, 200 the resistance change curve of wet cable insulation during baking, and some related issues that should be paid attention to in the selection and use of low-voltage power cables.
LV power cableIt is applied to important buildings, such as high-rise buildings, docks, stations and other key parts, such as fire control, fire pumps, smoke exhaust fans, automatic fire alarm devices and other electrical circuits, which is conducive to reducing the project cost and facilitating construction and maintenance. Secondly, the terminal end of low-voltage power cables is longer than ordinary cables and is not easy to bend. When laying cables, special tools should be used to cold work the dome to prevent damage the copper sleeve, keep the sealant and sealant to ensure that the insulation resistance meets the specification requirements.
You know the point of choosing cable
When choosing a cable, we only look at the price, regardless of where the cable comes from. Choosing a cable is a common mistake made by people, because there are now thousands of cable manufacturers in China. Their cable materials are different, models and specifications are different. Obviously, the price difference is even greater. If you only look at the price when choosing a cable, it is difficult to buy a high-quality cable.
As we all know, the safety of cables is related to the safety of people's lives and property. The country has strict quality control in this regard. Only cables produced by cable companies that meet national quality standards are qualified products that are worthy of people to buy. Through material selection, production technology, The safety factor and quality inspection have screened the cables, making the cables produced fully meet the national quality requirements.
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