Why do cables need to be armored and twisted?

1. Function of Cable armoring

Enhance the mechanical strength of the cable

The armor protective layer can be added to cables of any structure to enhance the mechanical strength of the cables and improve their anti-corrosion ability. It is a cable designed for areas that are prone to mechanical damage and highly susceptible to erosion. It can be laid in any way and is more suitable for direct burial in rocky areas.

2. Be on guard against being bitten by snakes, insects and rats

The purpose of adding an armor layer to cables is not only to enhance mechanical protection such as tensile strength and compressive strength and extend their service life; It has certain resistance to external forces and can also prevent snakes, insects and rats from tearing and biting, avoiding power transmission problems through the armor. The bending radius of the armor should be large, and the armor layer can be grounded to protect the cable.

3. Resistant to low-frequency interference

Commonly used armor materials include steel strips, steel wires, aluminum strips, aluminum tubes, etc. Among them, the armor layers of steel strips and steel wires have high magnetic permeability and excellent magnetic shielding effects. They can be used to resist low-frequency interference and enable the direct burial of armored cables without the need for pipe threading. They are cost-effective and widely used in practical applications. Stainless steel wire armored cables are used in vertical shaft chambers or steeply inclined roadways. Steel tape armored cables are used in horizontal or gently inclined roadways.

2. For cable stranding

1. Enhance flexibility

When copper wires of different specifications and numbers are twisted together in a certain arrangement sequence and twist pitch, they become conductors with larger diameters. The large-diameter twisted conductors are softer than single copper wires of the same diameter after twisting, and the wires made have good bending performance and are less likely to break during swing tests. For some wires that have requirements for flexibility (such as medical-grade wires), it is easier to meet the requirements.

2. Extend service life

In terms of electrical performance: When a conductor is electrified, it consumes electrical energy due to resistance and generates heat. As the temperature rises, it will affect the performance and lifespan of the insulating layer and protective layer materials. To ensure the efficient operation of the cable, the cross-sectional area of the conductor should be increased. However, large cross-sectional single conductors are not easy to bend and have poor flexibility, which is very unfavorable for production, transportation, installation and laying. In terms of mechanical properties, it is also required to have flexibility and reliability. By twisting multiple single wires together and twisting them together, the contradiction can be resolved.