In the construction of modern urban infrastructure, underground power pipelines are an important part of ensuring the stable operation of the power system. In order to ensure the safe and effective transmission of power lines, it is particularly important to choose the right pipe material and size. PVC pipes for underground electrical use have become one of the commonly used pipes in power engineering due to their excellent electrical insulation, corrosion resistance, lightness and low cost. This article will discuss in detail What size pvc pipe for underground electrical, related specifications and matters that need to be paid attention to during installation.
Basic specifications of PVC pipes for underground power
PVC pipes (polyvinyl chloride pipes) are one of the pipes widely used in laying underground power lines. They are mainly used to protect cables from external physical damage and prevent erosion by moisture and chemicals. The size of PVC pipes for underground power is generally divided according to the outer diameter, wall thickness and rated pressure of the pipe. Usually, the diameter of PVC pipes ranges from tens of millimeters to hundreds of millimeters, and the specific size will be determined according to the needs of the project.
1. Outer diameter (DN)
The outer diameter is one of the most important dimensions of the pipe and directly affects the laying of power cables. Common outer diameter sizes of PVC pipes for power are:
Small pipes: 25mm, 32mm, 40mm, 50mm
Medium pipes: 63mm, 75mm, 90mm, 110mm
Large pipes: 125mm, 160mm, 200mm, 250mm
2. Wall thickness (t)
Wall thickness refers to the thickness of the pipe, which directly affects the strength and pressure resistance of the pipe. For underground power pipelines, there are usually different levels of wall thickness standards, which are generally selected according to the load requirements and use environment of the pipeline. Common wall thickness specifications are:
Thick wall pipe: suitable for underground burial and high-strength environment
Standard wall pipe: suitable for general power pipeline laying
3. Length
PVC pipes are usually produced in sections of a certain length, with a common length of 4 meters or 6 meters, which is easy to transport and install.
Size selection criteria for underground power PVC pipes
When selecting underground power PVC pipes, we must first consider the purpose of the pipes, the specifications of the cables, and the actual conditions of the project. According to relevant standards such as the “Electric Power Engineering Design Code” and the “Electric Power Facility Safety Regulations”, the size selection of the pipes should follow the following principles:
1. Type and quantity of cables
Select pipes of corresponding sizes according to different voltage levels and the number of cables. For example, for the laying of low-voltage power cables, smaller pipes can generally be selected, while for high-voltage power cables or when multiple cables are laid in parallel, larger pipes need to be selected.
2. Pipeline carrying capacity
Underground pipes need to withstand external pressures such as soil and vehicles, so thicker PVC pipes need to be selected. If the soil conditions are poor or the pipes pass through densely trafficked areas, it is recommended to select high-strength thick-walled pipes.
3. Laying method
If it is laid vertically or over a short distance, a smaller diameter pipe may be selected. If it is laid horizontally over a long distance or needs to accommodate multiple cables, it is recommended to select a larger diameter pipe.
4. Future expansion
When selecting the pipe size, possible future cable expansion needs should be considered. Choosing the right size can reserve space for future maintenance or expansion, avoiding the need to re-lay the pipe in the future due to the pipe being too small.
5. Environmental protection and safety requirements
PVC pipes have excellent corrosion resistance and are suitable for long-term use in underground power facilities. In addition, PVC pipes have good fire resistance and also play an important role in safety protection in power engineering.
Installation precautions for underground power PVC pipes
After selecting the appropriate size of PVC pipe, the correct installation method is also crucial. Improper installation may cause pipe damage or cable failure, affecting the stable operation of power facilities. The following are several aspects that should be paid attention to when installing underground power PVC pipes:
1. Pipeline laying depth
PVC pipes should be buried at a certain depth below the ground, generally between 0.7 meters and 1.5 meters, to avoid external pressure. The specific depth is adjusted according to the soil conditions, traffic conditions and climate changes in different regions.
2. Pipeline connection method
PVC pipes are usually connected by hot melt connection or threaded connection. The connection parts should be constructed strictly in accordance with the specifications to ensure the sealing and pressure resistance of the interface.
3. Pipeline protective layer
Protective layers such as sand layers, concrete protective layers, etc. should be added around the pipeline to increase the pressure resistance of the pipeline and prevent soil corrosion.
4. Pipeline cleaning
Before installing the pipeline, ensure that the inside of the pipeline is clean and free of debris. Any debris may cause wear or damage to power facilities during cable installation.
5. Pipeline inspection
After the pipeline installation is completed, pressure test and compression test should be carried out to ensure that there is no water leakage, air leakage and other phenomena in the pipeline, and check whether the pipeline meets the design requirements.
The size selection of PVC pipes for underground power is a complex process, which needs to consider cable specifications, laying methods, soil conditions, future expansion and other factors. Common PVC pipe sizes range from 25mm to 250mm, and different power projects have different requirements for pipe sizes. Correct selection and installation of PVC pipes can ensure the safe and reliable operation of power facilities, and also facilitate later maintenance and expansion. When engineers select pipelines, they should consider various factors based on relevant national standards and industry specifications, and select the most appropriate PVC pipe specifications to ensure the efficiency and safety of power projects.
