YJV cable is one of the most commonly used power cables. In fact, when many people refer to "cables" today, they are generally referring to YJV cables. As the main cable in power transmission, YJV cable is like the arterial blood vessels in the human body or the trunk of a tree, indicating its important position in power transmission. YJV cables are generally found in urban underground passages (under manhole covers) or buried underground. There are often accidents where construction teams dig through power cables during construction, causing large-scale power outages, and these are usually YJV power cables. The following is a brief introduction to YJV power cables:
Copper-core (Aluminum-core) Cross-linked Polyethylene Insulated Polyvinyl Chloride Sheathed Power Cable
From the inside out, YJV cable consists of conductor, polyethylene insulator, filler (nylon, PVC composite material, etc.), and polyvinyl chloride outer sheath.
- The conductor is mostly copper-core. Currently, copper conductor is the most widely used conductor material in the market. Aluminum conductors are less used due to poor conductivity and lack of standards.
- The filler is mostly made of materials like nylon, which plays a role in protecting the cable core, equivalent to putting a "clothes" on the cable core.
- For armored power cables, a layer of steel tape armor is added between the filler and the sheath to provide pressure resistance when the cable is buried underground. The model of steel tape armored YJV cable is YJV22.
- The polyvinyl chloride sheath is the common PVC material we know.
GB/T12706.1-2008, IEC60502-1-1997 standards
Copper material and aluminum alloy material. The model code for aluminum-core cable is YJLV.
YJV cables are generally divided into four types: extra-high voltage, high voltage, medium voltage, and low voltage cables. The most commonly used in daily life are low-voltage power cables. High voltage and extra-high voltage cables are generally used for long-distance and ultra-long-distance power transmission, while medium and low-voltage power cables (35kV and below) are more common in general applications.
The maximum long-term allowable operating temperature of the cable conductor is 70°C. During a short circuit (with a maximum duration not exceeding 5 seconds), the maximum temperature of the cable conductor should not exceed 160°C. The ambient temperature during cable laying should not be lower than 0°C.
Power cables for distribution engineering, wire and cable for power transmission engineering, cables for mechanical and electrical installation projects, power transmission cables, cables for power supply installation systems and control systems, etc.
- The minimum bending radius during cable laying should not be less than 10 times the cable outer diameter.
- YJV/YJLV cables can be laid indoors, in trenches, and in pipes, and can also be buried in loose soil, but they cannot withstand external forces.
- YJV22/YJLV22 cables are laid underground and can withstand mechanical external forces but cannot bear large tensile forces.
- Special tools such as pay-off stands and guide rollers should be used for cable laying. Mechanical damage should be prevented during the laying process, and the cable should be kept away from heat sources.
- When laying cables through pipes, the inner diameter of the pipe should be at least 1.5 times the outer diameter of the cable. When multiple cables are laid through the same pipe, cable extrusion should be avoided, and the total area of the cables should not exceed 40% of the total inner area of the pipe.
Ordinary type, flame-retardant type, fire-resistant type, low smoke zero halogen type
YJV cables can consist of a single conductor or multiple conductors. The core numbers of YJV cables include 1-core, 2-core, 3-core, 4-core, 5-core, 3+1-core, 3+2-core, 4+1-core, etc. Among them, 3+1-core, 3+2-core, and 4+1-core are composed of two types of conductors with different functions: one is called phase wire, and the other is called ground wire, which is specially used for grounding.
Common specifications are 1mm², 1.5mm², 2.5mm², 4mm², 6mm², 10mm², 16mm², 25mm², 35mm², 50mm², 70mm², 95mm², 120mm², 150mm², 185mm², 240mm², 300mm², etc. For example, YJV3185+295 cable is composed of 3 phase wires of 185mm² and 2 ground wires of 95mm².
