How to distinguish the difference between low-voltage cables and medium high voltage cables?

There are many types of cables, but the most basic ones can be divided into low-voltage cables and high-voltage cables. But how should these two be distinguished? Some people say it's 250V, while others say it's 1000V. So how do we distinguish between high voltage and low voltage? Below are some materials compiled by the editor from the Cable Treasure website for your reference!

According to the industry standard electrical safety regulations in China, electrical equipment is divided into two types: high voltage and low voltage: high voltage: equipment with a ground voltage above 250V. Low voltage: Equipment with a ground voltage of 250V or below. According to the 2009 Power Line Safety Regulations, electrical work is divided into two types: high voltage and low voltage:

High voltage electrical equipment: voltage level of 1000V and above; Low voltage electrical equipment: voltage level below 1000V;

Usually, high-voltage lines refer to 3-10 kV lines; Low voltage lines refer to 220/380V lines.

The method to distinguish the voltage of high-voltage wires with the naked eye is as follows:

Understanding voltage levels

In China's power industry, common voltage levels include 220 volts, 380 volts, 1000 volts, 10000 volts, 35000 volts, 110000 volts, 220000 volts, 500000 volts, etc. Generally speaking, 220V and 380V are considered as low voltage, mainly used for household electricity; Above 35000 volts are high voltage, mainly used for power transmission. Between the two is medium pressure. It must be pointed out that touching high-voltage wires or conducting live work below the line poses great risks.

Identify low-voltage lines

Outdoor low-voltage lines have several obvious characteristics:

1) Basically, cement poles are used for support, and the cement poles are relatively short, generally not exceeding 5 meters.

2) The thickness of the wires is the same, and the number of wires is a multiple of 4, because low-voltage wires generally use a three-phase four wire system. If these characteristics are present, it can be determined that the line voltage of the wire is 380 volts and the phase voltage is 220 volts. (Phase voltage is the voltage of the line to ground, and line voltage is the voltage between two lines)

Identify medium and high voltage lines

Medium and high voltage transmission lines also have obvious characteristics:

1) If the thickness of the wires is the same, the number of wires is a multiple of 3. This is because transmission lines generally use three-phase transmission, and if these characteristics are present, it can be basically determined that the wire is 10000 volts.

2) If the thickness of the wires is different, the number of thick wires is a multiple of 3, and there are only 2 thin wires, assuming they are at the highest point. This is because thin wires are not used for power transmission, but for lightning protection, also known as lightning rods. If these characteristics are present, it can be determined that the wire is a high-voltage line.

Further identification of high-voltage lines

In order to improve the transmission capacity, high-voltage wires generally use split wires, which are commonly referred to as one phase per wire. Now, several wire harnesses are used together to replace the original one wire. Knowing this makes it easy to determine the voltage level of the wire.

1) One phase, one wire is 110000 volts;

2) One phase with two wires is 220000 volts;

3) One phase with four wires is 500000 volts.

There are not many opportunities for us to come into contact with high-voltage lines in our daily lives, but we still need to be careful when dealing with medium and low-voltage lines. Countless people die from electric shock every year, so no matter which type of cable is used, it is necessary to use national standard cables with quality assurance.