The terminal wire has many connection points on the electrical circuit, such as wires and wires, wires and switches, wiring pile heads of wires and electrical appliances, connection points of wires and shielding devices, etc. These connection points are different from other parts of the wire. At the joint, the insulation layer is peeled off. If the wrapping is poor and the two wires collide, it may form a short circuit, fever or electric spark.

1、 It is easy to cause wire collision

Generally, wires have insulation protection. As long as the insulation is not damaged, even if the two wires collide, it will not cause problems.

When laying wires, many electrical installation constructors often do not pay attention to the installation quality: do not install sleeves where insulating sleeves should be used; No junction box is installed at the place where the junction box should be used; It leads to continuous fever at the interface when the power is on, which makes the boards around gradually dry and carbonize, and then burns, causing fire alarm.

2、 It is easy to get fever due to excessive contact resistance

Difference measures shall be taken at the joint in real time, and it cannot be "seamless". If the contact area is less than the cross-sectional area of the conductor, the smaller the contact area of the connection point is, the greater the resistance is, the more likely the fever is. Therefore, the joint is always more prone to fever than other parts of the conductor. If the joint quality is good, the heat generated is not large, and the heat dissipation premise is good, the heat will be dissipated quickly, and the joint temperature will not rise too high to cause accidents; Otherwise, the possibility of causing accidents is very high.

3、 The connector of the wire should be reduced as much as possible

The wires that are often dragged and used should be the whole wire. There should be no joints in the middle. There should be no joints in the first place, such as the closed roof of the house.

4、 Poor placement quality

(1) If the connecting wire is not twisted as required, or even connected by hook method, the connection of the joint will not be firm and easy to be loose;

(2) The wires, switches and electrical appliances are connected through wire posts. Because of careless construction, the wire posts are not equipped with washers and the gongs are not tightened, which will also increase the contact resistance;

(3) The copper wire and aluminum wire are not connected according to the specified implementation method, which is often the same bed, and the contact resistance is also relatively high, causing hidden dangers;

(4) The cores of the multi-stranded wires are not twisted well, and some filaments (cores) are warped outward, forming a short circuit after mutual collision;

(5) During construction, the joints of each phase line are not staggered, which may cause accidents on the same section.

5、 The connector is loose after being opened for a long time

Some connectors are of good quality when they are placed, but because of thermal expansion and contraction, or long-term vibration, the connectors will become loose, such as the electrical lines in the bridgehead of a bridge, because the vehicles often produce violent vibration when they cross the bridge, which makes the connector of the conductor slowly loose, the contact resistance slowly increases, and the fever becomes more and more serious, leading to a fire alarm.

6、 Dust pollution

On the construction site, in the threshing plant and other open places, soil and dust often seep into the connection points of conductors, interfering with the contact between conductors, overheating the connection points and causing the burning of combustible objects around. Some electrical fire alarms generated in the threshing plant are the result of this.

7、 Oxidation occurs at conductor junction

In the environment of humid and corrosive air, it is easy to form an oxide layer on the conductor (copper oxide will appear on the copper conductor, and aluminum oxide is more likely to be generated on the aluminum conductor). The conductivity of the conductor of this oxide layer is very poor. For example, in the electroplating workshop of a factory, the conductor has been corroded by acid air for a long time, and the conductor forms an oxide layer on the surface, which leads to an increase in contact resistance, and high temperature is generated after electrification. In serious cases, the conductor even turns red. Fortunately, I feel real-time, Then it didn't become an accident.