Home improvement with copper wire single or good

Multi-core wire is easy to thread, but the connector is more troublesome and needs to be tinned or it is very easy to oxidize. And tin plating is best not to use very rubbish solder paste. Hard lines do not have this problem, but threading is more troublesome, especially large square. The general decoration single core wire is enough.

Multi-strand wire is a relatively large joint problem, and the current carrying capacity is better than that of a single core. The cable of the electric power is known. The cable is multi-core screwed together, but the cable joint is also not well treated, and the current city is equipped with The biggest problem with the power grid is the cable connector failure, as is the case with the 380V low voltage.

At home, the cable will be used in the decoration, often encounter soft wire, hard wire which is a good choice, BV wire is hard core, BVR is a multi-strand soft core. Two kinds of cables are the most common ones, but it seems to be a difficult choice in some unfamiliar lines. So is the copper wire good or single?

In fact, it is a pros and cons. Let's talk about the benefits of multi-strand: the multi-strand soft wire has a larger contact area than the single-strand copper wire, which is faster and more durable. For single-unit, everyone should have learned that physics should be known. The current is flowing on the surface of the wire. The contact area of ​​the single-stranded current is small. When the load is large, it is easy to generate heat. The same load, the cord can withstand the single-strand. It is easy to get hot. However, in the price of convenient multi-strand line is still more expensive than the single-strand, and in the wiring head should be carefully connected, otherwise it will cause the fire to easily (but the average electrician will know) so the overall view is still multi-share The cord is good.

The difference between single-strand copper wire and multi-strand copper wire is mainly in its structure. Since the multi-strand copper wire is soft and it is not easy to break the wire core, it is suitable for the occasion where the wire should follow the movement (such as the general distribution box and cabinet). On the door), where multiple wires are laid together (for wire laying and wire harness forming). Multi-stranded conductors are mostly used to control the line relative to single-stranded conductors. However, due to the structural reasons of the single-stranded wire, the corresponding multi-strand wire has a higher hardness, which is generally used for fixed laying (such as pipe-passing lines, etc.), and for single-strand copper wire, in the case of multiple strands of copper wire, it is in the line joint, It is convenient to connect the equipment. Multi-strand copper wire generally needs to be crimped or welded to the wire nose. However, the price of multi-strand copper wire is higher than that of single-strand copper wire; there is no hard and fast rule as the wire selection for laying on the line. In China, there is a stipulation that the maximum cross-sectional area of ​​a single-strand copper core wire is 6 mm 2 . However, in the case of mobile, multiple strands of soft copper wire are required to avoid accidents.

Does the current flow through the conductor as it normally flows through the surface?

In the case of direct current, there is current inside the conductor, no matter how large the cross section of the conductor is, the current density on the surface is equal.

AC, due to the skin effect, most of the current flows through the surface of the conductor, and there is basically no current flowing through the center of the conductor. At this time, the current density of the inside and the surface of the conductor will vary greatly, basically the skin depth. This formula can be used to approximate d=6.61/(f^0.5)

When choosing the cable and cable square, it is better to have a larger square (the difference is 100-200 yuan per disk), thinking that 70% of the current market is fake and inferior products. In this case, it is not the hard wire. Solved, the soft wire can only play a small role, it is important to see whether the cross section of the wire and cable can reach the square of the mark.