What problems are easy to occur at the terminal wire connector？
Terminal wire always has many connection points on the electrical circuit, such as wire and wire, wire and switch, wiring pile head of wire and electric appliance, connection point of wire and shielding device, etc. These joint parts 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 cause short circuit, fever or electric spark.
1、 It is easy to cause wire collision
Electric wires generally have insulation shelter. As long as the insulation is not damaged, even if the two wires collide, it will not cause problems. Accidents caused by non-standard electrical connectors, cable connectors, and terminal connectors are endless. The reason is that many electrical placement construction workers are not always careful about the placement quality when laying wires: do not install sleeves where the 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 during power-on, gradually drying and charring the surrounding wood, and then burning, causing fire alarm
2、 It is easy to get fever due to excessive contact resistance
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 based on the principle that the resistance is inversely proportional to the conductive area; The higher the resistance is, the more likely it is to have a fever. Therefore, the joint is always more likely to have a fever than other parts of the conductor. If the quality of the joint is good, the heat generated is not large, and the premise of heat dissipation is good, the heat will be quickly dissipated, and the temperature of the connection point will not rise too high to cause an accident. On the contrary, the possibility of causing an accident is great. The wire is hooked, and the contact area of the wire is up to 1/8 of the cross-sectional area of the wire, so the resistance of the connection part is 8 times of that of other parts, The fever is similar to 8 times, and this part is prone to accidents. The hook joint, under the external vibration phenomenon, will also show the condition of intermittent connection, which may show electric spark, which is easy to cause the burning of surrounding combustible materials. Because the contact resistance of the joint is too large, it may also produce high temperature, which can make the metal conductor discolor and even melt, cause the conductor insulation layer to fire and other materials to burn, and become a fire accident
3、 The connector of the wire should be reduced as much as possible
The wire that is often dragged and used should be the whole wire. There should be no joint in the middle. There should be no joint 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 connection method, the connection of the joint will not be firm, and it is easy to be loose. There is a cotton processing plant, and the wires in the closed roof (the empty pavilion in the roof interlayer) are also connected by hook connection method once. Because the mouse moves in the closed roof, it touches the wire joint, which causes the joint to be loose, causing electric sparks, causing flying flocs in the closed roof to catch fire, and the fire rapidly spreads along the wire, which has become a serious fire accident
(2) The wires, switches and electrical appliances are connected through wire posts. Due to careless construction, the wire posts are not equipped with washers and the gongs are not tightened, which will also increase the contact resistance. For example, in a restaurant, the distribution box is due to such reasons, which leads to the melting of the conductors, and the molten beads fall on the cardboard box below, causing a fire alarm
(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 wire core of the multi-strand wire is not twisted well, and part of the wool (wire core) is warped outward, which forms a short circuit after collision. For example, a department store did not twist the multi-strand copper wire well when installing the wire socket, and some copper wires are warped and exposed, and when it touches another phase wire, it will generate a short circuit after being electrified, causing a fire alarm
(5) During construction, the joints of each phase line are not staggered, and accidents may also occur on the uniform section. For example, when a mobile crane is stacked in a ginning plant and uses a wire truck with a joint to enter the warehouse for unloading in violation of regulations, the wire joint is pulled off and the interphase short circuit between the joints is generated, resulting in electric sparks, causing jute burning and causing a serious accident
5、 The connector is loose after being opened for a long time
Some connectors are of good quality when placed, but due to thermal expansion and contraction, or long-term vibration, the connectors will be loose, such as the electrical circuit in the bridgehead of a bridge, because the vehicle often produces violent vibration when crossing 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 spaces, there are often soil and dust seeping into the connection points of conductors, interfering with the contact between conductors, causing the connection points to overheat, causing the burning of combustible objects around the threshing plant, and some electrical fire alarms generated from this are
7、 Oxidation occurs at conductor junction
In a humid and corrosive atmosphere, 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 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, resulting in an increase in contact resistance. After being electrified, high temperature is generated. In serious cases, the conductor even turns red. Fortunately, I feel real-time, Then it didn't become an accident.
