Temporary Power Use 008: Recent insights gained from learning about distribution boxes, regarding their installation
Thread Content
The last edit to this post was made by Shutong on 2024-7-4 at 06:34. 1. Settings for distribution boxes: Distribution boxes and switch boxes should be constructed from cold-rolled steel plates or flame-retardant insulating materials. The thickness of the steel plates should be between 1.2 and 2.0 mm; the thickness of the steel plates used for switch boxes must not be less than 1.2 mm, while that used for distribution boxes must not be less than 1.5 mm. The surface of these boxes should also be treated to prevent corrosion. The external structure of distribution boxes and switch boxes should be capable of protecting against rain and dust. Distribution boxes and switch boxes should be numbered, with their names and purposes indicated; multiple power distribution circuits within a distribution box should also be marked. Power isolation switches should be installed in the main distribution box, sub-distribution boxes, and switch boxes. These isolation switches should be placed at the power inlet side, that is, at the first electrical device after the wires enter the box. Isolating switches should be isolating devices that provide a visible break point when disconnected, enabling the simultaneous disconnection of all poles of the power supply. Air switches or leakage protectors cannot be used as isolating switches, nor can slab switches. Wires should enter and exit the electrical box through its bottom surface, and the entry and exit points of the wires in the box should be protected with sleeves. The electrical mounting board inside the electrical box shall be a metal plate or a non-wooden, flame-retardant and insulating electrical mounting board. If a metal plate is used, it must be electrically connected to the box body. The installation of electrical boxes must meet the following requirements: Distribution boxes and switch boxes should be installed properly and firmly. The vertical distance from the center of fixed electrical boxes to the ground should be 1.4 to 1.6 meters, while for mobile electrical boxes, this distance should be between 0.8 and 1.6 meters. No materials that could hinder operation or maintenance should be piled up in front of distribution boxes and switch boxes; there should be sufficient space and passages around them for two people to work simultaneously. Electrical boxes should be installed in dry, well-ventilated areas at normal temperatures, away from vibrations and impacts.
This post was last edited by Shutong on 2024-7-4 06:44. 2. Wiring installation: The electrical wiring at the construction site should be installed either overhead or underground. Overhead lines must never be laid along scaffolding, trees, or other structures. Overhead lines should be laid along poles, supports, or walls and secured using insulators; binding wires must be insulated. The maximum sag of overhead wires outdoors must be at least 4 meters from the ground level at the construction site; it must also be at least 6 meters away from vehicle lanes, and at least 1 meter away from buildings (including external scaffolding). Indoor wiring should be installed at a height of no less than 2.5 meters above the ground. When cables are laid along walls, their maximum sag from the ground must be at least 2 meters. It is strictly prohibited for cable lines to pass through scaffolding to reach the construction site; cables must be laid underground to reach the site. When cables are installed vertically upward to upper floors, they must not be connected to the external scaffolding. The vertical shafts and holes in the construction site should be utilized to their full extent; the cables can also be laid along the exterior walls using sleeves, with at least one fixing point per floor. The burial depth for underground cable laying shall be no less than 0.7 m; protective sleeves shall be installed when cables pass through areas prone to damage, such as roads. Cable lines for the zero-grounding protection system must use five-core cables. Wires and cables should maintain intact outer covers and good insulation.
Study hard*, make progress every day. Thank you, Teacher Dong, for sharing this
Distribution boxes and switch boxes should be made of cold-rolled steel plates or flame-retardant insulating materials of standard thickness, and should be treated to prevent corrosion. The outer structure must be weather- and dust-proof; the internal structure should be clearly numbered and labeled with names and purposes. A power isolation switch must be provided, and the installation location must be dry, well-ventilated, and free of obstacles that could interfere with operation. Wires need to be protected by sleeves when entering and exiting to ensure safety. .
Go to bed early and get up early, study materials on seas and rivers, and learn from the teacher!*
Thank you, Mr. Dong, for sharing! Learn a little bit every day to make progress.
Thank you for sharing; let’s all learn about switch boxes together! Thanks to the Shutong Database for sharing; many urgently needed materials can be obtained from Shutong!
Thank you to the Book Boy Database, and thanks to Teacher Dong for his selfless sharing!
Study hard*, make progress every day. Thank you, Teacher Dong, for sharing this
Thank you for the link to the Shutong database, and thanks to Teacher Dong for sharing it! !
There is a house of gold in books; thank you, Teacher Dong, for sharing! ! !