In China, where products are rapidly updated, many new things are slowly being accepted by people. Let's take the piercing clamp as an example. You can see the pictures. Maybe friends who have never used it can't understand it. In fact, it is very simple. , It is mainly composed of these things, the piercing blade, the shell, and the torque nut. It has two bayonet ports, and each of the bayonet ports has a zinc-plated copper alloy blade. The hardness is sufficient. One side is clamped on the main line, and the other side is clamped on For the branch line to be divided, the blade in the bayonet slowly penetrates the insulation layer of the cable under the action of the torque nut, and the asbestos layer can also penetrate. So when is the most appropriate time to use the nut force? The blade cannot be penetrated. Whether it touches the copper core inside, this is why the torque nut is used. The penetration force of the blade has finally determined the most suitable force in the continuous experimentation of the technicians. When you take the wrench to screw the torque nut After it is broken, the blade has reached the most reasonable level of contact. You can rest assured that the regular product guarantees that its contact surface is sufficient. The puncture clamp is a disposable product, and the reason why it cannot be reused is two The second use is very dangerous, so I deliberately chose a torque nut to break it directly. Some friends ask if the one-core cable can still be understood, but the five-core cable is not easy to understand. In fact, it is very simple. They are all the same. The total outer skin is removed, and there are 5 cables inside, and you can just put them on the cards one by one.
The piercing clamp is supported by two insulating shells which are separated up and down and connected by a screw threaded with a torque screw. There are two conductors made of special alloys that can be cross-contacted with wires hidden in the insulating support shell. The piercing clamp has a torque nut and a piercing structure. The torque nut is used to ensure constant contact pressure and good electrical contact. Together with the piercing structure, the installation is simple and reliable. You only need to visually check whether the torque nut is broken and the position of the wire during installation. Reliable quality can be guaranteed if it is appropriate. After testing, the contact resistance and line insulation resistance meet the requirements of the construction specification, and the temperature rise of the joints is lower than that of the same diameter cable when the load is energized. The use of the piercing clamp has little effect on the mechanical and electrical properties of the main line.
In the use of imported products, I feel that the reliability of metal torque nuts is higher than that of plastic torque nuts. For example, a few times when I saw the wire clip accidentally fall from the hands of workers at the installation site, the metal torque There is no problem with the nut, and the plastic torque nut of the plastic torque nut was tripped because of this. Another time, when they just took it from the outdoor into the room in the winter of the previous year, they installed it. As a result, the plastic torque nut was only pulled a few times and it was connected. The plastic retainer was cracked together, and it was no problem to replace it with a metal torque nut. Of course, since the price of plastic torque nuts is lower than that of metal torque nuts, Party A will still consider it.
Will the puncture process damage the cable and reduce the tensile strength of the contact?
The damage to the cable by the general puncture clamp is very small, but there is, basically it can be said that it rarely affects the electrical conductivity of the main line, and the tensile strength is basically not affected. However, the domestic product that can make this product is basically not Many, if you come across fake and inferior products, then you are not sure, some are not working, and some clamps are clipped, hehe, even imported ones are not necessarily good, so I generally recommend that before buying, put the wire The material (copper, aluminum) and wire diameter of the cable is best to tell us first, we can adjust the contact area of the piercing clamp in some aspects. There is no fixed formula to calculate, because the shape of the cable is different (mainly circular), The tooth shape of the clamp is generally dominated by arc-shaped tines.Generally, large cables are multi-core. The actual contact situation is often that the larger the stress point, the more the contact, and the smaller the contact. We believe that the conductivity of a metal is mainly determined by its mechanical properties. For example, a very thin copper wire, if you can cool it well, then its current-carrying capacity can be very large, such as 100A, a direct way to evaluate a cable clamp is the temperature rise. I personally think that if its temperature rise is smaller than that of the branch cable, it can basically be used, but its technical parameters are strictly required by the national standard. of.