MindMap Gallery Building electrical engineering construction technology
The knowledge points related to the building electrical part in the construction technology of building electrical engineering are only for reference by examiners and engineering personnel.
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Building electrical engineering construction technology
Division and construction procedures of building electrical engineering
Division of building electrical engineering
Outdoor electrical
Power distribution room
Power supply trunk
Electric power
Electrical installation lighting
Backup and uninterruptible power supplies
Lightning protection and grounding installation
Building electrical engineering construction procedures
Construction procedures for power transformation and distribution projects
Installation sequence of switch cabinets and distribution cabinets
Unpacking inspection → Secondary transportation → Basic frame production and concealed installation → Cabinet fixation → Busbar connection → Secondary line connection → Test adjustment → Power supply operation acceptance
Dry-type transformer construction sequence
Unpacking inspection → secondary transportation of the transformer → installation of the transformer body → installation of accessories → transformer handover test → inspection before power transmission → acceptance of power transmission operation.
Construction procedures for power supply trunk lines and indoor wiring
Bus duct construction sequence
Unpacking inspection → Bracket installation → Single-section bus duct insulation test → Bus duct installation → Insulation test before power on → Power delivery acceptance
Indoor ladder frame cable construction sequence
Cable inspection → cable handling → cable laying → cable insulation test → hanging signs → quality acceptance
Trunk wiring construction sequence
Measurement and positioning → bracket production → bracket installation → wire trough installation → ground wire connection → distribution in the trough → line test
Metal conduit construction sequence
Measurement and positioning → Bracket production and installation (when laying open pipes) → Conduit prefabrication → Conduit connection → Ground wire jumper
Construction sequence of pipe threading
Select the conduit→Put the lead in the tube→Bind the wire and lead→Place the retainer (when laying the metal conduit)
Electrical power engineering construction procedures
Construction sequence of surface-mounted power distribution box
Basic frame production and installation → distribution box installation and fixation → wire connection → inspection before power transmission → power transmission operation
Power equipment construction sequence
Equipment unpacking and inspection→Equipment installation→Motor inspection and wiring→Motor drying (when damp)→Control equipment installation→Inspection before power supply→Power supply operation
Electrical lighting engineering construction procedures
Construction sequence of concealed lighting distribution box
Fixing the distribution box → piping → threading in the pipe → connecting wires → inspection before power transmission → power transmission operation
Lighting tool construction sequence
Unpacking and inspection of lamps→Lamp assembly→Concealed wiring of lamps→Inspection before power supply→Power supply operation
Lightning protection grounding device construction procedures
The construction procedure of the lightning protection grounding device: grounding body construction → grounding trunk line construction → down conductor laying → voltage equalizing ring construction → air-termination strip (air-termination pole, air-termination net) construction
Construction technical requirements for building electrical engineering
Technical requirements for construction of power supply trunk lines and indoor distribution lines
Technical requirements for busway construction
Bus duct unpacking and inspection
The bus duct is well sealed against moisture, the accessories are fully supplied and free from defects, the shell should have no obvious deformation, the overlapping surface of the bus duct bolts should be flat, and the plating coverage should be complete without peeling or pitting.
The static contacts on the plug-in bus duct should be free of defects, have a smooth surface and complete plating.
For bus ducts with protection level requirements, the protection level of the products and accessories should be checked, and their markings should be complete. Fireproof bus ducts should have fire protection ratings and combustion reports.
Bus duct bracket installation requirements
The bus duct brackets should be installed firmly without obvious distortion. When fixed with metal hangers, anti-sway brackets should be provided.
The diameter of the round steel hanging brackets of the indoor power distribution bus duct shall not be less than 8mm, and the diameter of the round steel hanging brackets of the indoor lighting bus duct shall not be less than 6mm.
The fixed points of bus ducts laid horizontally or vertically should be set at one point per section, and each layer should not be less than one bracket. The spacing should meet the requirements of the product technical documents. Brackets should be set 0.4m-0.6m away from the corner. The fixed point position should not be It should be set at the busway connection or tap unit.
Bus duct installation and connection requirements
The straight section of the bus duct should be installed straight. The horizontal and vertical deviation of the distribution bus duct should not be greater than 1.5‰; the maximum deviation of the total length should not be greater than 20mm; the horizontal deviation of the lighting bus duct should not be greater than 5mm, and the vertical deviation should not be greater than 10mm. The bus duct should be concentric with the shell, and the allowable deviation should be ±5mm.
When the bus duct crosses the deformation joint of the building, a deformation device should be installed; the linear laying length of the bus duct exceeds 80m, and expansion joints should be installed every 50m-60m.
The bus duct should not be installed directly under the water pipe.
The connection between bus duct sections should not be set up where it passes through the floor or wall. Special component supports fixed to the building (structure) should be set up at the place that passes vertically through the floor. The cavity should be surrounded by a height of 50mm and above. Waterproof platform and take fireproof sealing measures.
When connecting bus duct sections to sections, the bus ducts and shells of two adjacent sections should be aligned, and the phase sequence should be correct. The bus bars and shells should not be subject to additional stress after connection; the bus bar connection method should comply with the requirements of product technical documents; bus duct connection The protection level of the components used should be consistent with the protection level of the busway body.
A torque wrench should be used to fasten bus duct connections, and the tightening torque of lap bolts should comply with the requirements of product technical documents or specifications; the contact resistance of bus duct connections should be less than 0.1Ω.
The exposed conductive parts such as the metal casing of the bus duct should be reliably connected to the protective conductor, the metal casings of each section of the bus duct should be reliably connected, and the full length of the bus duct should be reliably connected to the protective conductor at no less than 2 places; the branch bus duct should be reliably connected to the protective conductor. The metal shell end should be reliably connected to the protective conductor; the material and cross-section of the connecting conductor should meet the design requirements.
Inspection before powering on bus duct
The bus duct should be alkaline inspected or tested before being powered on. The AC power frequency withstand voltage test of the high-voltage busbar should comply with the handover test regulations; the insulation resistance of the low-voltage busbar should not be less than 0.5MΩ.
When checking the connection of the tapping unit, the grounding contact should be in contact before the phase line contacts, and the contacts should be tightly connected. When withdrawing, the grounding contact should be disconnected after the phase line contacts.
Check that the wiring phase sequence of the bus duct, power distribution cabinet, and electrical equipment should be consistent.
Technical requirements for construction of ladder frames, pallets and trough boxes
On-site acceptance requirements for ladder frames, pallets and trough boxes
The equipment should be complete and the surface should be smooth and not deformed; the coating of the steel ladder frame, pallet and trough box should be complete and free of rust.
Plastic trough boxes should be undamaged and uniform in color. If there is any objection to the flame retardant performance, batch sampling should be sent to a qualified laboratory for inspection.
The coating of aluminum ladder frames, pallets and trough boxes should be complete and there should be no distortion, flattening or surface scratches.
Bracket installation requirements
Welding brackets are not allowed on building steel structural components, and hot processing of openings is not allowed.
The spacing between horizontally installed brackets should be: 1.5m-3 meters; the spacing between vertically installed brackets should not be greater than 2 meters.
When metal hangers are used for fixation, the diameter of the round steel shall not be less than 8mm, and there shall be anti-sway brackets. There shall be fixed brackets at the branch or end 0.3m-0.5m.
Installation requirements for metal ladder frames, pallets and trough boxes
Special connection accessories should be used at the turns and branches of metal ladders, trays and trough boxes for cables. The bending radius should not be less than the minimum allowable bending radius of cables in metal ladders, trays and trough bridges. The minimum allowable bending radius of cables should comply with relevant regulations. Regulation.
When the wiring trough box is laid up and down on the same side as the horizontal pipe, it should be installed above the water pipe; when it is laid parallel to the hot water pipe and steam pipe, it should be laid below the hot water pipe and steam pipe; the minimum distance between them should comply with Relevant acceptance specifications.
Ladder racks, pallets and trough boxes laid in electrical shafts where they pass through floor slabs and across different fire protection zones should have fire isolation measures.
For cable ladders or trays laid in electrical shafts, the fixed brackets should not be installed on the cross arms that fix the cables, and load-bearing brackets should be installed every 3-5 floors.
For ladder frames, pallets and trough boxes installed outdoors, rainproof measures should be taken when entering indoors or distribution boxes, and there should be drainage holes at the bottom of the trough boxes.
Ground bonding requirements for metal ladder frames, pallets and trough boxes
When the total length of metal ladder frames, pallets and trough boxes is not more than 30 meters, there should be no less than two reliable connections to the protective conductor.
When the total length is more than 30 meters, a grounding connection point should be added every 20m-30m, and both the starting and ending ends should be reliably grounded.
The two ends of the connection between non-galvanized metal ladder frames, pallets and trough boxes should be connected to protective connecting conductors, and the cross-section of the protective connecting conductors should comply with the design requirements.
When galvanized metal ladder frames, pallets and trough boxes are not protected by jumper connection conductors, there should be no less than 2 connection fixing bolts with lock nuts or lock washers at each end of the connection plate.
Conduit construction technical requirements
On-site acceptance requirements for metal galvanized conduits
Check product quality certificate
The galvanized layer should be completely covered and there should be no rust spots on the surface. The hardware accessories should be complete and free of blisters.
For hot-dip galvanized steel buried in the soil, the thickness of the galvanized layer should not be less than 63 μm.
If there is any objection to the quality of galvanizing, batch sampling should be sent to a qualified laboratory for testing.
Bracket installation requirements
Conduit brackets are not allowed to be welded on load-bearing steel structural components, and openings are not allowed to be heated.
When the conduit is fixed with a metal hanger, the diameter of the round steel shall not be less than 8mm, and an anti-sway bracket shall be installed.
Fixed brackets should be installed 0.3m-0.5m away from the box, branch or end.
Construction requirements for metal conduits
Steel conduits shall not be connected by butt welding; galvanized steel conduits or steel conduits with a wall thickness less than 2 mm shall not be connected by casing welding;
Galvanized steel conduits, bendable metal conduits and metal flexible conduits shall not be welded together;
The distance between the surface burial depth of concealed ducts and the surface of buildings and structures should not be less than 15mm. When plastic conduits are grooved and buried in the wall, cement mortar with a strength grade of not less than M10 should be used for protection.
When the conduit passes through a closed or protective closed partition wall, a pre-embedded casing should be installed. The production and installation of the pre-embedded casing should meet the design requirements. The distance between the two ends of the casing extending out of the wall should be 30mm-50mm. The conduit must pass through a sealed wall. Wiring boxes should be installed on both sides of the wall casing and sealed.
The bending radius of the conduit
The bending radius of exposed conduits should not be less than 6 times the outer diameter of the conduit. When there is only one bend between two junction boxes, the bending radius should not be less than 4 times the outer diameter of the conduit.
The bending radius of a conduit buried in concrete should not be less than 6 times the outer diameter of the conduit. When buried directly underground, the bending radius should not be less than 10 times the outer diameter of the conduit.
The bending radius of the cable guide should not be less than the minimum allowable bending radius of the cable, and the minimum allowable bending radius of the cable should comply with the specifications.
The exposed electrical conduits should be arranged neatly, the fixed points should be evenly spaced, and the installation should be firm; there should be fixed pipe clamps within the range of 150mm-500mm from the edge of the ignition cabinet, table, box, tray, etc. in the terminal and elbow, and fixed pipe clamps in the middle straight section The maximum spacing between pipes should comply with the regulations; the junction box or transition box (box) used for exposed piping should be an exposed box (box).
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Technical requirements for construction of electrical lighting devices
Technical requirements for building lightning protection and grounding construction