A power cord is a wire that transmits electric current. Usually the method of current transmission is point-to-point transmission. Power cords can be divided into AC AC power cords and DC DC power cords according to their use. Generally, AC power cords are wires that pass high-voltage AC power. Because of their high voltage, these wires require uniform standards to obtain safety certification before they can be officially produced. The DC line basically passes the direct current with a lower voltage, so the safety requirements are not as strict as the AC line, but for safety reasons, countries still require unified safety certification.

For home appliances, although the power cord is only an accessory, it plays a vital role in the use of the home appliance. If the power cord is broken, the entire appliance cannot be used. Household power cords should adopt BVV2×2.5 and BVV2×1.5 type wires. BVV is the national standard code and is a copper sheathed wire. 2×2.5 and 2×1.5 represent 2-core 2.5 square millimeters and 2-core 1.5 square millimeters, respectively. In general, 2×2.5 is used as the main line and trunk line, and 2×1.5 is used as a single electrical branch line and switch line. Single-phase air-conditioning dedicated line uses BVV2 × 4, and a dedicated ground wire is also provided.

1. Power cord copper and aluminum monofilament drawing

Commonly used copper and aluminum rods for power cords, at room temperature, use a wire drawing machine to pass through one or several stretch die holes to reduce the cross-section, increase the length, and increase the strength. Wire drawing is the first process of various wire and cable companies, and the primary process parameter of wire drawing is mold matching technology.

2. Single wire annealing for power cord

When the copper and aluminum monofilaments are heated to a certain temperature, the method of recrystallization is used to improve the toughness of the monofilament and reduce the strength of the monofilament to meet the requirements of the wire and cable for the conductive core. The key to the annealing process is to eliminate the oxidation of the copper wire.

3. Stranding of power cord conductors

In order to improve the flexibility of the power cord and facilitate the installation of the device, the conductive core is formed by twisting multiple monofilaments. From the stranding method of the conductive core, it can be divided into regular stranding and irregular stranding. Irregular stranding is divided into bundle stranding, concentric stranding, extraordinary stranding and so on. In order to reduce the occupied area of the wire and reduce the geometric size of the power cord, the compaction method is also used in the twisted conductor, so that the popular circle is mutated into a semicircle, a sector shape, a tile shape and a compact circle. This kind of conductor is mainly used on the power cord.

4. Power cord insulation extrusion

The plastic power cord mainly adopts extruded solid insulation layer. The main technical requirements of plastic insulation extrusion are:

4.1. Degree of bias: The bias value of the extruded insulation thickness is the main indicator of the degree of squeezing to work. Most of the product structure size and its bias value have clear rules in the specification.

4.2. Lubricity: The surface of the extruded insulation layer must be lubricated, and it must not show poor quality problems such as rough appearance, scorching, and impurities

4.3. Density: The cross-section of the extruded insulating layer should be dense and strong, free of pinholes visible to the naked eye, and free of air bubbles.

5. The power cord is wired

Regarding the multi-core power cord, in order to ensure the molding degree and reduce the shape of the power cord, it is generally required to twist it into a round shape. The mechanism of stranding is similar to that of conductor stranding, because the stranding pitch diameter is larger, and most of the twist-free methods are used. The technical requirements of the cable formation: First, the root of the special-shaped insulated core turns over and cause the cable to twist; the second is to avoid the insulation layer from being scratched.