Everything in the world has its own attributes and levels. What's more, cable products are widely used and have a wide range of types. Even if you are in the industry, you don’t know everything. This article compiled by today’s editor is about the rated voltage and the number of cable cores. A simple analysis of the relationship between, hope to help you better understand.

Selection conditions for 1-5 core cables of 1kV and below

1. Single core cable

To avoid or reduce the intermediate joints when the circuit is longer, the working current is larger or the circuit is laid underwater, or the single-core cable has better comprehensive technology and economy than the multi-core cable, the single-core cable can be selected; low-voltage DC power supply circuit , Single-core cable can be used when needed.

2-core cable

When the neutral point of the power supply of 1kV and below is directly grounded, the number of cores of the single-phase circuit cable. When the protection line and the neutral line share the same conductor, a 2-core cable should be used; for the DC power supply loop, 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 cores of the single-phase circuit is: when the protection line and the neutral line 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 in addition to being used as a protective ground, also transports unbalanced current and short-circuit current in the power system. Its size is determined by unbalanced current and short-circuit current, but generally it should not be less than 1/2 of the phase line.

For three-phase four-wire low-voltage power distribution systems of 1kV and below, when the protection line and the neutral line share the same conductor, a 4-core cable should be used instead of a 3-core cable plus a single-core cable to form a loop, or directly Use 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 operating state of a single-core cable, which is likely to cause power frequency interference.

5-core cable

Three-phase four-wire low-voltage power distribution systems of 1kV and below, some electrical equipment power distribution lines with high reliability requirements, and some communication and automation equipment that must not only ensure that the electrical is not damaged, but also must be anti-interference grounding. The 5-core TN-C low-voltage power distribution system makes the protection line (PE line) and the neutral line (PN line) independent. The cross-sectional area of the cable core is generally 3 large 2 small or 4 large 1 small or 5 large.