Article 14. 1.2 stipulates that butt welding of metal conduits is strictly prohibited; Galvanized and steel conduits with wall thickness less than or equal to 2mm shall not be connected by sleeve fusion welding. Article 14. 1. 1.2 stipulates that when the galvanized conduit is connected by thread, special fixing clips should be used at both ends of the joint to cross the grounding wire.
According to the specification, it can be determined that:
1, galvanized steel pipe is best connected by thread when it is dark;
2. Galvanized conduit with a wall thickness greater than 2mm can be welded by casing when it is concealed electrically;
3. For galvanized conduits with wall thickness less than 2mm, casing welding should not be used for electrical concealed matching.
Extended data
Design content
Modern architectural styles tend to be diversified, with large height, large area and complex functions, and the contents of electrical design are becoming more and more complicated and there are many projects. The narrow sense of building electrical design only refers to the electrical design in civil buildings, and the broad sense should include outdoor projects such as industrial buildings, structures, roads and squares.
Traditional building electrical design only includes power supply and lighting, but today it is generally described as strong current and weak current. Power supply, lighting and lightning protection belong to strong electricity, and the rest, such as telephone, TV, fire protection and building automation, belong to weak electricity. This classification is based on the level of voltage, emphasizing that the contents of fire protection, telecommunications and automatic control added in electrical design are completely different from those in traditional electrical design and easy to understand, so it is quickly accepted by people.
However, this voltage classification method is not rigorous, such as: the secondary control loop of power equipment, its voltage may be very low; The linkage in the fire fighting circuit should not be completely separated from the distribution box.
Another example is the functional design of civil air defense design, lightning protection design and security design, whose content is not only the alarm of weak current signal, but also the interlocking reaction of power and lighting. Another example is lightning protection grounding, which requires both strong electricity and weak electricity, and has the trend of equipotential connection, which is actually difficult to separate. If the electrical design is only based on the voltage level, it will inevitably lead to too many strong and weak electronic jobs and unclear boundaries.
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