1kV and below the selection conditions for 1-5 core cables

1. Single core cable

When the circuit is long and the working current is large or when the circuit is laid underwater, in order to avoid or reduce the intermediate joint, or when the single-core cable has better comprehensive technology and economy than the multi-core cable, the single-core cable can be selected; the low-voltage DC power supply circuit, the single core cable can be used when required.

2 core 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 loop, when the protection wire and the neutral wire share the same conductor, should use a 2-core cable; for the DC power supply circuit, a 2-core cable should be used.

3 core cable

When the neutral point of the power supply of 1kV and below is directly grounded, the number of cable cores of the single-phase loop is: when the protection wire and the neutral wire are independent, a 3-core cable should be used.

4 core cable

For 4-core cables (3+1 cables) of 1kV and below, the 4th core is not only used as protective grounding but also transmits unbalanced current and short-circuit current in the power system. Its size is determined by the unbalanced current and short-circuit current, but generally not less than 1/2 of the phase line.

For a three-phase four-wire low-voltage power distribution system of 1kV and below, when the protection wire and the neutral wire share the same conductor, a 4-core cable should be used instead of a combination of a 3-core cable and a single-core cable to form a circuit or direct The method of using the metal sheath or armor layer of the 3-core cable as the neutral wire. Otherwise, when the 3-phase current is unbalanced, it is equivalent to the running state of the single-core cable, which is easy to cause power frequency interference.

5 core cable

The three-phase four-wire low-voltage power distribution system of 1kV and below, some electrical equipment distribution lines with high-reliability requirements, and some communication and automation equipment that not only ensure electrical damage but also anti-interference grounding, should be The TN-C low-voltage power distribution system with 5 cores is adopted so that the protection wire (PE wire) and the neutral wire (PN wire) are independent of each other.

Through the above introduction, do you have a deeper understanding of the relationship between the rated voltage of the cable and the number of cable cores? If you are interested in our wire and cable products, you can consult.