Electrical technical disclosure
Summary of disclosure: installation of lighting distribution board
1. Operation process:
1.1 process flow:
Installation requirements of distribution box and panel - → snap line positioning - → surface installation of distribution box (panel) - → processing of distribution box (panel) - → fixing of distribution box (panel) (surface installation and concealed installation) - → insulation shake test
1.2 installation requirements of distribution box (panel)
1.2.1 the distribution box (panel) shall be installed in a safe, dry and easy to operate place. When the distribution box (panel) is installed, its bottom opening is generally 1.5m from the ground; The bottom opening is 1.2m away from the ground during surface installation; The distance between the bottom opening of surface mounted watt hour meter plate and the ground shall not be less than 1.8m. In the same building, the height of similar panels should be consistent, and the allowable deviation is 10 mm.
1.2.2 wood bricks and iron parts required for the installation of distribution box (panel) shall be embedded. Hanging distribution box (panel) shall be fixed with metal expansion bolts.
1.2.3 the iron distribution box (panel) shall be painted with one coat of antirust paint and then two coats of grey paint. All kinds of embedded iron parts shall be painted with antirust paint, and obvious and reliable grounding shall be made. When the wire is led out of the panel, the wire hole of the panel shall be smooth without burr, and the metal panel shall be equipped with insulation protection sleeve.
1.2.4 the iron panel with appliances, the door with appliances and the metal shell of electrical appliances of the distribution box (panel) shall be provided with obvious and reliable PE protective ground wire (PE wire is yellow and green two-color wire, braided soft bare copper wire can also be used), but PE protective ground wire is not allowed to be connected in series by box or box body.
1.2.5 the wiring of the distribution box (panel) shall be arranged in order, bound into bundles, and fixed at the moving parts. Proper redundancy shall be reserved for the lead out and lead in of the panel to facilitate maintenance.
1.2.6 the wire core shall not be damaged or the wire core shall be too long at the place where the wire is exploited. The wire head shall be firm and reliable. The multi strand wire shall not be crimped by coil, and the crimping terminal shall be installed (except for the wire with crimping hole). If it is necessary to punch and crimp with top wire, the multi strand wire shall be rinsed with tin before crimping, and the number of strands shall not be reduced.
1.2.7 all kinds of knife switches and automatic switches installed on the panel surface of the distribution box (panel) shall not be charged when they are in the open circuit state (except for special circumstances).
1.2.8 vertically installed switches and fuses are connected with power supply at the upper end and load at the lower end. The left side (facing the disk) of the horizontal loader is connected with the power supply, and the right side is connected with the load.
1.2.9 the power supply of the power indicator on the distribution box (panel) shall be connected to the outside of the main switch, and a separate fuse (power supply side) shall be installed. The position of the disc brake should correspond to the branch road, and a card frame should be installed under it to indicate the road type and capacity.
1.2.10the neutral line n of TN-C low-voltage distribution system shall be on the box or panel, and repeated grounding shall be done at the place where it is led into the grounding main line.
1.2.11 AC, DC or different voltage levels of power supply in lighting distribution box (panel), with obvious signs.
1.2.12 the lighting distribution box (panel) shall not be made of combustible materials, and the wooden distribution box (panel) used in dry and dust-free places shall be flame retardant.
1.2.13 in the lighting distribution box (panel), neutral line N and protective ground wire (PE line) bus bars shall be set respectively. The neutral line N and protective ground wire shall be connected on the bus bar and shall not be twisted and numbered.
1.2.14 the exposed screw hole in the base center of magnetic plug-in fuse shall be filled with insulation to prevent discharge to ground. The metal screw of magnetic plug should not be exposed, but should be filled with fire paint.
1.2.15 for the spiral fuse installed in the lighting distribution box (panel), the power line shall be connected to the terminal of the middle contact, and the load line shall be connected to the threaded terminal.
1.2.16 when the material of PE line is the same as that of phase line, the section shall be selected according to the requirements of thermal stability and shall not be less than that shown in Table 1.
Minimum section of PE line table 1
Phase line core section s (M m2) minimum section of PE line
(M2) core section of phase line s (M2) minimum section of PE line (M2)
S≤16 S S＞35 S/2
Note: if the non-standard surface is obtained by using this table, the conductor with the closest standard section shall be selected, but it shall not be less than: bare copper wire 4mm2, bare aluminum wire 6mm2, insulated copper cable 1.5mm2, insulated aluminum wire 2.5mm2.
1.2.17if PE protective ground wire is not a part of power supply cable or cable outer sheath, according to the mechanical strength requirements, the cross section shall not be less than the following values:
2.5 mm 2 with mechanical protection; 4 mm2 without mechanical protection.
1.2.18 the phase line of the bus on the distribution box (panel) shall be painted with color, and the phase a (L1) shall be painted with yellow; Phase B (L2) should be painted green; Phase C (L3) should be painted red; Neutral line n shall be painted light blue correspondingly; The protective earth wire (PE wire) shall be painted with yellow and green.
1.2.19 the electric appliances and instruments on the distribution box (panel) shall be firm, flat, clean, evenly spaced, the copper terminals shall not be loose, the opening and closing shall be flexible, and the parts and components shall be complete. The arrangement spacing shall meet the requirements of Table 2.
Requirements for arrangement spacing of electric appliances and instruments Table 2
Minimum dimension of spacing (mm)
Between the side of instrument or more than 60 between the side and panel edge
The distance between instrument top surface or outlet hole and panel edge is more than 50
Between the side faces of the brake or more than 30 between the side face and the disc edge
More than 40 between upper and lower outlet holes (separated by card frame)
Above 20 (not separated by card frame)
Top or bottom of plug-in fuse and outlet hole plug-in fuse specification (a) above 10 ~ 15 20
Over 60 50
Cross section between top or bottom surface of instrument, rubber cover gate and wire of outlet hole
(M2) 10 and below 80
1.2.20 the lighting distribution box (board) shall be installed firmly and level, and its vertical deviation shall not be greater than 3mm; During installation, there should be no gap around the lighting distribution box (board), the edge around the panel should be close to the wall, and the contact part between the box and buildings and structures should be coated with anti-corrosion paint.
1.2.21 galvanized round cap machine screws shall be used to fix the panel, and the spacing shall not be greater than 250mm, and shall be evenly symmetrical at the four corners.
1.2.22 when the panel of distribution box (panel) is large, it shall be reinforced with iron lining. When the width exceeds 500mm, the box door shall be double door.
1.2.23 the distance between the back of the vertical panel and the building shall not be less than 800mm; The foundation section steel should be straightened before installation and then embedded and fixed. The horizontal error should not be more than 1 mm per meter, and the total error of the whole length should not be more than 5 mm. The distance from the bottom of the panel to the ground shall not be less than 500mm. The distance between the iron frame surface mounting panel and the building shall be easy for maintenance.
1.2.24 the vertical panel shall be set in the special room or equipped with fence, and the iron fence shall be grounded.
1.3 snap line positioning:
According to the design requirements, find out the location of the distribution box (panel), and snap the line according to the overall dimensions of the box (panel); The purpose of snap line positioning is to find out the embedded parts more accurately when there are embedded wood bricks or iron parts, or to find out the position of metal expansion bolts.
1.4 surface mounted distribution box (panel)
Iron frame fixed distribution box (panel)
Straighten the angle steel, measure the size, draw the saw line, cut and bend, drill holes and weld. When bending, use square ruler to find the bottom, then use electric (gas) welding to weld the butt joint firmly, and make the buried end into swallow tail, then remove rust and brush anti rust paint. Then the swallow tail end of the iron frame shall be embedded firmly with cement mortar according to the elevation. When embedding, the straightness of the iron frame and the distance between holes shall be paid attention to, and the iron frame shall be stabilized after accurate measurement with plumb line and level ruler. After the cement mortar is solidified, the distribution box (panel) can be installed.
Fixed distribution box (panel) with metal expansion bolt
The metal expansion bolt can be used to fix the distribution box (panel) on the concrete wall or brick wall. The method is to find out the exact location of the fixed point according to the requirements of snapping line positioning, and use electric drill or percussion drill to drill holes at the fixed point. The hole diameter should be just enough to embed the expanded pipe part of the metal expansion bolt into the wall, and the hole should be straight and not skew.
1.5 processing of distribution box (panel)
The plate surface can be made of steel plate. Measure the steel plate with square ruler according to the size and cut after drawing the cutting line. After cutting, flat the edges and corners with a flat file. The assembly wiring of the panel is as follows:
1.5.1 physical arrangement: lay the panel flat, and then place all electrical appliances and instruments on it for physical arrangement. According to the design drawings and the specifications and quantity of electric appliances and instruments, the best position should be selected to meet the spacing requirements, and ensure convenient operation and maintenance and beautiful appearance.
1.5.2 processing: after the position is determined, the square ruler shall be used for alignment, the horizontal line shall be drawn, and the hole spacing shall be evenly divided. Then remove the electric appliance and instrument and drill the hole (the hole diameter should match the insulating nozzle). Derusting after drilling, brushing antirust paint and grey paint.
1.5.3 fixing electric appliances: after the paint is dry, install the insulating nozzle, and level and align all electric appliances and instruments, and fix them firmly with screws.
1.5.4 panel wiring: according to the specification, capacity and location of electric appliances and instruments, the section and length of the conductor shall be selected and cut for assembly. The wires after the coil shall be arranged in order and bound into bundles. When pressing the head, leave a proper margin for the wire, cut the wire core, and press firmly one by one. However, the crimping terminal is required for multi strand wires. For example, the vertical panel should be fixed first after opening, and then wiring.
1.6 fixing of distribution box (panel)
1.6.1 fixing of surface mounted distribution box (panel)
A. When the surface mounted distribution box (panel) is fixed on the concrete wall or brick wall, the concealed pipe, the concealed junction box and the exposed pipe are adopted. If there is a junction box, clean up the sundries in the box first, then straighten out the wires, distinguish the branch and phase sequence, and bind them into bundles according to the branch. After the box (panel) is located, lead the wire end to the box or panel, exploit the wire end one by one, and then crimp it on the appliance one by one. At the same time, press the PE protective ground wire in an obvious place, and fix the box (panel) after adjusting it. After the installation of the panel with more electric appliances and instruments, the instrument should be used to check whether there is any error. After the adjustment is correct, try to send the power. Fill in the position and number the card in the card box.
B. When the distribution box (panel) is fixed on the wall of wood structure or light steel keel, reinforcement measures shall be taken. If the piping is concealed in the panel wall and there is a concealed junction box, the box opening shall be flush with the wall, and the wooden panel wall shall be provided with fireproof treatment, which can be protected by applying fireproof paint or adding fireproof material lining. In addition to the above requirements, the fixation method is the same as above.
1.6.2 fixation of concealed distribution box:
According to the size of the reserved hole, first find the elevation and horizontal size of the box, and fix the box, then fill the periphery with cement mortar and level it, and then install the panel and face after the cement mortar solidifies. If the bottom of the box is flush with the external wall, the wall plastering shall be done after the metal mesh is fixed on the external wall. Plastering shall not be carried out on the bottom of the box. The installation panel surface shall be flat, the peripheral gap shall be even and symmetrical, the face (door) shall be flat and not skew, and the vertical force of screws shall be even.
1.7 insulation shake test:
After all the electrical appliances of the distribution box (panel) are installed, the 500V megohmmeter is used to measure the insulation of the line. Telemetry items include between phase lines, between phase lines and neutral lines, between phase lines and protective ground wires, and between neutral lines and protective ground wires. The two persons shall carry out the shake measurement and make records at the same time, which shall be filed as technical data.
2. Finished product protection:
2.1 after the distribution box (panel) is installed, the finished product protection measures shall be taken to avoid damaging and polluting the electric appliances and instruments.
2.2 when installing the box (panel) panel (or facing),