Speaking of wires and cables, we have to mention copper and aluminum in their main materials. The question is, what is the difference between copper core and aluminum core wires and cables? Which is better? Let’s get to know~
There are several ways to distinguish whether the wire core is copper core or aluminum core
First, from the model of the wire, the meaning of the letters in the model is as follows: B – fixed laying; X – rubber insulation; L – aluminum core (copper core is not represented by letters); W-chloroprene sheath; Y – polyethylene sheath. For example: bxw – copper core rubber insulated neoprene sheathed wire; Blxw – aluminum core rubber insulated neoprene sheathed wire.
Secondly, it is intuitively distinguished from the core material. The core of copper core wire is copper, and the core of aluminum core wire is aluminum. Because copper is golden yellow and aluminum is white. You can directly peel off a small section of wire core to see the color to distinguish whether it is copper core or aluminum core.
Warm tip: now many aluminum core wires will be coated with a layer of yellow material on the surface of the core, commonly known as copper-clad aluminum wire, which also looks yellow. The difference methods are as follows: first, scrape the surface layer, the copper core wire is still yellow, and the aluminum core wire is white; Second, burn with a lighter. The flame of copper core wire is blue and the flame of aluminum core wire is white. So we must polish our shining eyes and not be blinded by unscrupulous businesses~
Difference between aluminum wire and copper wire
1. The cut-off flow of copper wire and aluminum wire is different;
2. Aluminum wire is relatively cheap;
3. Aluminum wire is lighter;
4. The mechanical strength of aluminum wire is poor;
5. The aluminum wire is easily oxidized at the connecting wire end, and the temperature rise will occur after the connecting wire end is oxidized
6. The internal resistance of copper wire is small. Aluminum wire has greater internal resistance than copper wire, but it dissipates heat faster than copper wire. It is mainly due to different current carrying capacity and mechanical strength. The resistivity of copper is 0.017 and that of aluminum is 0.029. Therefore, the current carrying capacity of aluminum is about 80% of that of copper. Mechanical strength copper is much better.
Comparison of advantages and disadvantages between copper core wire (cable) and aluminum core wire (cable)
Low resistivity of copper core: the resistivity of aluminum core is about 1.68 times higher than that of copper core;
Good ductility of copper core;
High strength of copper core: the allowable stress at room temperature can reach 20 for copper and 15.6kgt/mm2 for aluminum;
Copper core fatigue resistance: aluminum is easy to break after repeated bending, while copper is not easy to crack;
Copper core has good stability and corrosion resistance: copper core has oxidation resistance and corrosion resistance, while aluminum core is easy to be oxidized and corroded.
Although the aluminum core is relatively cheap, in addition to being cheap, in many cases, the rest is chicken feathers, especially for some products, we should be cautious.
Selection of wire and cable models
(1) When selecting wires and cables, the purpose, laying conditions and safety shall be considered;
For example, according to different purposes, power cables, overhead insulated cables, control cables, etc. can be selected;
(2) According to different laying conditions, general plastic insulated cable, steel strip armored cable, steel wire armored cable, anti-corrosion cable, etc. can be selected;
(3) According to the safety requirements, non flame retardant cables, flame retardant cables, halogen-free flame retardant cables, fire-resistant cables, etc. can be selected.
Selection of wire and cable specifications
1) When determining the service specification (conductor section) of wires and cables, generally, the selection conditions such as heating, voltage loss, economic current density and mechanical strength shall be considered.
2) According to experience, because the load current of low-voltage power line is large, the section is generally selected according to the heating conditions, and then the voltage loss and
3) Mechanical strength; Low voltage lighting line has high requirements for voltage level, so the section can be selected according to the allowable voltage loss conditions, and then the heating conditions and mechanical strength can be checked;
4) Although aluminum core cables and are cheap, copper cables have outstanding advantages in cable power supply, especially in the field of underground cable power supply. The underground use of copper core cable for power supply has the characteristics of low accident rate, corrosion resistance, high reliability and convenient construction and maintenance.