Common cable failures and safety requirements for embedded cables
Wire and cable -- common faults of cable lines include mechanical damage, insulation damage, insulation dampness, aging and deterioration of insulation, overvoltage, cable overheating, etc.When the above mentioned fault occurs in the line, the power supply of the fault cable should be cut off, the fault point should be found, the fault should be checked and analyzed, and then the fault should be repaired and tested. The power supply can be restored only after the fault is eliminated；
1. Conductor diameter: when purchasing conductor, the user should pay attention to whether the conductor diameter is in conformity with the specification on the qualification certificate.If the cross section of the conductor is too small, it is easy to make the conductor hot and cause short circuit.It is recommended to use square lighting of 1.5 mm or more for home lighting lines.High-power household appliances such as air conditioners and microwave ovens should use wires of 2.5 square millimeters or above.
2. Standard use: wiring shall be standardized.For fixed lines, BV single - core wires are the best way to connect pipes.Pay attention not to damage the wire when wiring, pay attention not to damage the wire when decorating the room.Do not connect halfway through the route;Do not touch the wire when it is connected with the electrical box (box).In addition, household appliances that consume large amounts of electricity, such as air conditioners, should be powered by a separate power line;It is best to keep a distance between the weak and the strong wires.
3. Wire surface marking: according to the national standard, the wire surface shall be marked with manufacturer's name, product model and rated voltage continuously.This is conducive to the use of wire in the process of timely discovery of the problem, find the manufacturer, consumers must pay attention to this point when buying wire.At the same time, consumers should pay attention to the manufacturer's name, product model and rated voltage on the certificate, as well as the printed mark on the wire surface, to prevent counterfeit products.
4. Appearance of wire: consumers should pay attention to the appearance of wire, the insulation and sheath layer shall not be damaged, the logo shall be printed clearly, and the wire of hand mold shall not feel greasy.From the cross section of the conductor, the insulation or sheath thickness of the entire circumference of the conductor should be uniform, should not bias the iron core, insulation or sheath should be a certain thickness。
Electric wires and cables -- safety requirements for buried cables
1. When the cables are crossed, the high-voltage cables should be under the low-voltage cables.If one of the cables is running through pipe protection or separated by a partition within 1m before and after the intersection, the minimum distance allowed is 0.15m.
2. When the cable is close to or crossed with the heat pipe, the minimum distance of parallel and crossing shall be 0.5m and 0.15m respectively if the insulation measures are taken.
3. When the cable intersects with the railway or road, the tube shall be inserted for protection, and the protection tube shall extend beyond 2m from the track or road surface.
4. The distance between the cable and the building foundation shall ensure that the cable is buried far away from the building;Cables entering the building should be protected through pipes, which should also be in the water outside the building.
5. The grounding distance between the underground directly buried cable and the general grounding device is 0.15-0.5m;The cable buried directly underground is generally no less than 0.7m deep and is buried under the permafrost.