Please tell us the reasons for cable burning, and what are the major reasons for the damage of wires

The position is more than 30 meters from the compartment, and the plastic outer sheath is all scorched within 30 meters, and the armor is red. "1. In this place, if there is no joint, it should be affected by external forces, resulting in line problems. For example:

Heavy pressure, heavy hammer, most likely heavy vehicle over. 2. Is the environmental condition of the line the worst? If so, the first point is more likely to cause problems.

3. The switch trips because of the grounding fault or short circuit protection after the line has a problem. That's all I can think about.

In the event of a single-phase grounding fault in the cable, due to the large impedance and small arc current, the protection circuit breaker cannot be moved, but the arc current temperature is very high, which burns out the cable insulation, and finally leads to a metallic short circuit, and the protection circuit breaker trips.

There is a layer of insulating rubber skin on the outside of the cable, and there is also a layer on the outside of the copper wire, and there are generally four wires in the cable, three live wires, and one ground wire, and now they are all five, and there are five in three fires and one zero one. If it is crushed or knocked by a heavy object, the insulation between the wires inside is damaged, and there will be a short circuit between phases when the power is transmitted, and the current will be huge, which will burn the cable, or the insulation of the entire line will be damaged.

It may be that a single-phase grounding fault occurs at 30 meters of the cable, due to the large impedance and small arc current, the protection circuit breaker cannot be moved, but the arc current temperature is very high, and the cable insulation is burned out, and finally the metal short circuit is caused, and the protection circuit breaker trips.

Did the front-end switch trip? It may be that the switch refuses to jump, or the switch action is too slow and takes too long.

The following six are important causes of wire and cable obstruction:

Clause. 1. Environment and temperature. The external environment and heat source of the cable will also lead to excessive cable temperature, insulation breakdown, and even anger.

Clause. Second, the insulation is damp. This is also a common occurrence and usually occurs at the point where the cable is buried or in the pipe. For example, if the cable discussion is not made up properly and the discussion is made under the requirements of wet weather, the discussion will be flooded or mixed with water vapor.

Over time, water branches are formed under the action of the electric field, which gradually infringes on the absolute flange strength of the cable and causes obstacles.

Clause. 3. Damage by external forces. According to incomplete statistics, external damage can be described as the No. 1 "killer" of wires and cables.

Due to the acceleration of China's urbanization rate, almost every will be doing a larger range of reform projects, in the construction process of the city differential level damage to the cable, some will directly block the cable completely, and will leave the cable "sequelae, so that the protection of the cable is too low, and the rate of progress of the cable obstruction."

Clause. Fourth, perpetual overload and trouble. When people are overloaded, things will fall, and cables are no exception. Due to the thermal effect of the current, the flow of the load through the cable must cause the conductor to heat up.

At the same time, the skin effect of the electric charge.

As well as the eddy current consumption of steel armor and the consumption of insulating medium, additional heat will also be generated, so that the temperature of the cable will increase. During constant overload operation, excessive temperature will accelerate the aging of the insulation and even cause the insulation to break down. Especially in the scorching summer, the temperature rise of the cable often leads to the breakdown of the thin insulation of the cable, so in the summer, the cable is also very obstructed.

Clause. Fifth, the cable discussion obstruction. Cable discussion is the thinnest key point of the cable course, and it often occurs when the cable discussion is hindered by the direct failure of the staff (poor construction).

In the process of making the cable, if the construction staff discusses the original network such as insufficient crimping and insufficient heating, the insulation of the cable head will be very low, which will cause chaos.

Clause. 6. Chemical corruption. The cable is directly buried in the area with the effect of liquid rolling acid and alkali, which will cause the armor, lead skin or outer sheath of the wire and cable to be corrupted, and the cover layer will be subjected to chemical corrosion or electrolytic corrosion for a long time, resulting in the failure of the cover layer and low insulation, which will also lead to the obstruction of the cable - the cable corrosion environment of the unit is commensurate and severe.

Consequences after cable breakage:

1. Causing leakage and personal electric shock;

2. Short-circuit fever, causing disaster, causing huge property losses and possibly endangering life;

3. Cause power outages and maintenance, resulting in economic losses.

Broken skin and slight damage of the cable will not affect the electrical performance, but it will reduce the current carrying capacity of the cable due to water ingress corrosion.

If it is seriously damaged, the insulation resistance to the ground will come down, and the sock-shaped discharge to the ground will be overheated, and the long-term overheating will age, and finally the cable will break down. Use heat shrink cable patches to wrap the cable and restore the full level of insulation.

Is it easy to repair a burned cable? Good repair, the repair method is, generally in accordance with the strict requirements of the electrician layout of the line, are can be pumped out, if the wire can not be pulled out, it means that the line hand bucket road is not professional to connect, or there is no pipe at all, directly deal with the disturbance of the potato buried in the concrete, this kind of need to think of other ways. How do I replace the wire when it is pulled out?

First of all, we need to find the joints at both ends of the wire, then disassemble the joints, use scissors to reduce the bent part, and then wrap the wire around one end of the wire on the pliers, and slowly pull it out little by little. When wearing a new conduit, you can apply lubricating oil to the wire, and then tie the wire and the wire tightly, and use the method of pulling the wire with ease to thread it.

Caused by electricity leakage, personal electric shock** accident.

Short-circuit fever can lead to disasters that cause huge property damage and may be life-threatening.

Cause power outages, maintenance, and economic losses.