Characteristics and uses of 1-core, 2-core, 3-core, 4-core and 5-core

1-core cable: In order to avoid or reduce intermediate joints when laying circuits with long lines and large operating currents or underwater laying, or when single-core cables have better overall technical and economic benefits than multi-core cables, single-core cables can be selected. Suitable for low-voltage DC power supply circuit, single-core cable can be used when necessary.

2-core cable（2 core 2.5mm pvc flexible cable、2 core 4mm flexible cable、2 core 2.5mm dc cable）: When the neutral point of the power supply of 1kV and below is directly grounded, the number of cable cores in the single-phase circuit. When the protective line and the neutral line share the same conductor, a 2-core cable should be used. Suitable for DC power supply circuit, 2-core cable should be used.

3-core cable（3core 4mm flexible cable、flexible three core cable、2.5mm 3core flexible cable）: When the neutral point of the power supply of 1kV and below is directly grounded, the number of cable cores in the single-phase circuit is: When the protection line and neutral line are independent, a 3-core cable should be used.

4-core cable（4x2.5sqmm flexible cable、cable flexible 4 core、4 core 8mm flexible cable）: 4-core cable (3+1 cable) of 1kV and below. In addition to being a protective ground, the 4th core also transports unbalanced current and short-circuit current in the power system. Its size is determined by the unbalanced current and short-circuit current, but generally it should not be less than 1/2 of the phase line.

5-core cable（5 core flexible cable、5 core 4mm flexible cable）: three-phase four-wire low-voltage power distribution system of 1kV and below, some electrical device distribution lines with higher safety requirements, and some communication centers and automation that must ensure both electrical safety and anti-interference grounding Equipment should use a 5-core TN-C low-voltage power distribution system to make the protective line (PE line) and neutral line (PN line) independent. The cross-sectional area of ​​the cable core is generally 3 large and 2 small or 4 large and 1 small. 5 big.