③ When using the hand simmer, the movement should be moderate and the force should not be too strong.
Key points of bridging process between electric well bridge and grounding trunk line: ① process flow: positioning → prefabricating support → installing support → laying grounding trunk line → bridging → identification.
Construction process of strong and weak current shaft 1 Detailed drawing of distribution box trunking connection process key points of conduit outlet box process: ① process flow: reservation and embedding → distribution box installation → piping → box device installation → wiring → grounding.
② When the cable tray is bent, if the maximum cable diameter is less than 70mm, the bending angle of the cable tray is not more than 30 degrees.
4、 Metal trunking and cable tray grounding construction process bridge bridging detail drawing spray plastic bridge bridging galvanized bridge connection process points: ① process flow: installation of trunking → grounding connection → identification.
② Special straight sleeve and curved sleeve shall be used for straight pipe connection and curved connection.
⑧ It is convenient for inspection, and the laying position does not hinder the disassembly and maintenance of the equipment.
Detailed drawing of construction process of grounding trunk line of electric well.
JDG connection construction process 6.
II.
③ In order to ensure that large section cables can meet the requirements of cable bending radius when laid in small bridge frames, l should meet L ≥ 10d-w/2.
⑤ The grounding main line must be set up along the vertical strong and weak current bridge, and the bridge must be effectively bridged with the grounding main line, and the bridging fasteners should use anti loose fittings.
Set a support 0.5m between the high and low joints according to the two ends of junction boxes, boxes, cabinets, corners, turns, deformation joints and the three ends of T-joints.
⑤ For 32mm pipe diameter and above, there should be no less than 2 set screws at both ends of the connecting sleeve.
When there is no design requirement, the minimum clear distance from the pipeline should meet the requirements.
When connecting straight pipes, the two nozzles shall be in the center of the conduit.
⑤ The length of steel cable rack in straight section is more than 30m, and the length of aluminum alloy or glass fiber reinforced plastic cable tray is more than 15m, with expansion joints; Compensation devices shall be set at the deformation joints where the cable tray crosses the building.
② The installation position of the distribution box is correct, the components are complete, and the installation elevation of the row box ensures the bottom is flat; There is a lock nut when the conduit enters the box; The cover of the concealed distribution box is close to the wall.
What are the difficulties of power construction? Bridge and pipeline construction is a major difficulty.
First, hot galvanized materials shall be used for grounding trunk lines and metal fittings; Second, the minimum allowable section of the line should meet the requirements: ③ when laying horizontally along the building wall, the height from the ground should be 250-300mm; The gap with the building wall is 10-15mm.
⑨ During cable wiring, the bending radius of cable tray, trunking and pipe shall not be less than the minimum bending radius of cable.
They have comprehensively expounded the key points of the process from the following aspects, which is very useful for guiding the construction: 1.
④ The switch in the panel (box) acts flexibly and reliably, with the circuit of leakage protection.
Keep the spacing uniform.
⑥ The connection is reliable.
④ The surface of the grounding wire is 15-100mm along the length direction, and is painted with yellow and green stripes respectively.
⑥ When there are no requirements in the design, the installation spacing of horizontal supports is 1.5-3m, and the spacing of vertically installed supports is not more than 2m.
Cable bridge grounding construction process 5.
When the maximum cable diameter is less than or equal to 50, the bending angle is not more than 45 degrees.
Indoor JDG pipe open laying construction process 1.
Construction process of strong and weak current shaft 2.
5、 Detailed drawing of JDG connection construction process key points of process: ① process flow: snapping line and positioning → prefabrication processing (pipe cutting and bending) → pipeline connection.
During welding, the weld joint should be full without omission, the corrosion prevention of the welding part should be complete, and the lap length and welding method requirements should meet the following table: ⑦ the grounding down lead should be marked.
3、 Detailed drawing of connection construction process at the direction change of cable tray; key points of cable tray expansion joint and cable tray connection process: ① finished accessories should be used.
If the supplier does not specify the size of accessories or the size data is insufficient, this standard specification shall be followed.
⑦ The bolts between the bridge and the support and the bolts of the bridge connecting plate are fastened without omission, and the nuts are located outside the bridge; When the aluminum alloy bridge is fixed with the steel support, there are anti electrochemical corrosion measures for mutual insulation.
④ Set screws shall be operated with special tools.
② Materials shall be selected according to the design requirements.
The bending radius of the pipe shall not be less than 10 times of the pipe diameter.
② The two ends of the connecting plate between non galvanized cable trays are connected with copper core grounding wire, and the minimum allowable cross-sectional area of the grounding wire is not less than 4mm2; The two ends of the connecting plate between galvanized cable trays are not connected with grounding wires, but the two ends of the connecting plate are not less than 2 connecting and fixing bolts with locking nuts or locking washers.
③ The connection is reliable, and the fasteners are provided with anti loosening measures during crimping; Claw pads shall be added to the span connection of spray tank frame.
⑤ Lighting box, support and conduit shall be reliably grounded.
⑧ The cable tray is laid under the flammable and explosive gas pipeline and thermal pipeline.
Metal trunking process 4.
⑥ The conduit body should be grounded, the connection does not need to be grounded, and the pipeline should not be used as the equipment grounding wire..
Connection construction process of cable bridge diversion 3.
④ When the metal cable tray is laid horizontally, the height from the ground should generally not be less than 2.5m, and when it is laid vertically, it should be protected by a metal cover plate (except for the special places of distribution room, electric shaft and technical floor).
④ When the total length of the cable tray is not more than 30m, it should be connected to the grounding main line at least 2 places; When the total length is more than 30m, the connection point with the grounding main line should be increased every 20m ~ 30m.
③ The wiring in the panel (box) is neat, the cross-sectional area of the wire pressed on both sides of the screw under the washer is the same, the wire connection on the same terminal is not more than 2, and the anti loose washer and other parts are complete; In the lighting panel (box), busbars of zero line (n) and protective ground line (PE line) are set respectively, and the zero line and protective ground line are distributed through the busbars.
Most weak current people have many questions about this.
The action current of the leakage protection device is not more than 30mA, and the action time is not more than 0.1s.
