A. Construction preparation
1 material requirements:
1. 1 iron distribution box: the box body should have certain mechanical strength, the surrounding area should be smooth and undamaged, the paint should not fall off, and the thickness of the second floor should not be less than 1.5mm, but flame-retardant plastic plates should not be used as the second floor. All kinds of electrical appliances in the box should be installed firmly, the wires should be arranged neatly and pressed firmly. It should be the products of two designated factories with product certificates.
1.2 galvanized materials include angle steel, flat iron, iron sheet, machine screws, bolts, washers, round nails, etc.
1.3 insulated conductor: the model and specification of conductor must meet the design requirements, and have product certificate.
1.4 other materials: electrical instrument, fuse (or fuse), terminal board, insulating nozzle, aluminum sleeve, card frame, flexible plastic pipe, wooden brick nail, plastic tape, black tape, antirust paint, grey paint, solder, flux, covered electrode (or calcium carbide, oxygen), cement and sand.
3. Operating conditions:
3. 1 The installation position of dark distribution box shall be reserved with the civil structure.
3.2 When the iron frame or bolt is embedded, the wall structure should pop up the construction horizontal line.
3.3 When installing the distribution box panel, plastering, shotcreting and painting should be completed.
B. Operating process
1, distribution box installation requirements:
1. 1 The distribution box should be installed in a safe, dry and easy-to-operate place. When the distribution box is installed, its bottom mouth is generally1.5m; Stay away from the ground; When exposed, the bottom opening is1.2m; Stay away from the ground; In the same building, the distance between the bottom opening of the surface-mounted watt-hour meter board and the ground should not be less than 1.8m, and the heights of similar boards should be consistent, with the allowable deviation of 10 mm.
1.2 elastic line positioning:
Find out the location of the distribution box according to the design requirements, and locate the box (panel) according to its external dimensions. The purpose of elastic line positioning is to find out the position of embedded parts or metal expansion bolts more accurately under the condition of embedding wood bricks or iron pieces.
1.3 surface-mounted distribution box (box):
Fix the distribution box on the iron frame, straighten the angle steel, measure the size, draw the cut line, saw, bend, drill and weld. When bending, align it with a square ruler, then weld the butt joint firmly with electric (gas) welding, and make the embedded end dovetail, and then remove rust and brush anti-rust paint. According to the elevation, use cement mortar to bury the swallow tail end of the iron frame. When burying, attention should be paid to the straightness of the iron frame and the distance between holes. Only after accurately measuring the line drop and level can the iron frame be stably injected. The distribution box can only be installed after the cement mortar is solidified.
Metal expansion bolt fixed distribution box
Metal expansion bolts can be used to fix the distribution box on a concrete wall or brick wall. The method is to find out the exact position of the fixed point and drill a hole in the fixed point with an electric drill or an impact drill. The hole diameter should just bury the expanded part of the metal expansion bolt into the wall, and the hole should be straight and not skewed.
1.4 processing of distribution box;
The disk surface can be made of thick plastic plate, metal composite plate or steel plate. Take the steel plate as an example, measure the steel plate with a square according to its size, draw a cutting line and cut it. File the edges and corners with a flat file after cutting.
The disk surface can be made of thick plastic plate, metal composite plate or steel plate. Take the steel plate as an example, measure the steel plate with a square according to the size, draw the cutting line and cut it. File the edges and corners with a flat file after cutting.
The assembly wiring of the disk surface is as follows:
1.5 physical arrangement: put the panel flat, and then put all electrical appliances and instruments on it for physical arrangement. According to the design drawings, specifications and quantity of electrical appliances and instruments, the best position is selected to meet the spacing requirements and ensure convenient operation and maintenance and beautiful appearance.
1.6 machining: after the position is determined, align it with a square ruler, draw a horizontal line and divide the hole spacing equally. Then remove the electrical appliances and instruments, and drill holes (the hole diameter should be consistent with the insulating nozzle). After drilling, derust, brush antirust paint and gray paint.
1.7 fixing electrical appliances: after the paint is completely dried, install insulating nozzles, straighten and align all electrical appliances and instruments, and fix them firmly with screws.
1.8 wiring of distribution board: according to the specifications, capacity and location of electrical appliances and instruments, select the section and length of conductor, and cut and assemble. After winding, the wires should be arranged neatly and tied into bundles. When pressing the head, leave an appropriate margin for the wires, cut off the cores and press them firmly one by one. But multi-strand wires need wire pressing terminals. If it is a vertical tray, the tray panel should be fixed before opening, and then wiring.
2. Fixation of distribution box:
2. 1 When the surface-mounted distribution box is fixed on a concrete wall or brick wall, there are two ways: concealed piping, concealed junction box and exposed piping. 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 tie them into bundles according to the branch. After the box (disc) is positioned, lead the thread ends into the box or disc, exploit the thread ends one by one, and then press them on the appliance one by one. At the same time, the PE protective ground wire is pressed on the obvious place, and the box (disk) is fixed after straightening. After the panel with more electrical appliances and meters is installed, first check whether there are any errors in the meters, and then try sending again after adjustment. The cards in the card box will be filled and numbered.
2.2 when the distribution box is fixed on the wooden structure or light steel keel retaining wall, reinforcement measures should be taken. When the pipeline is laid in the enclosure wall and there is a concealed junction box, it is required that the mouth of the box is flush with the wall surface, and the wooden enclosure wall is fireproof, which can be protected by brushing fireproof paint or lining fireproof materials. In addition to the above requirements, the relevant fixing methods are as above.
2.3 Fixation of dark distribution box:
According to the reserved hole size, first find out the elevation and horizontal size of the box body, and fix the box body, then fill and smooth the periphery with cement mortar, and then install the disk surface and stick the face after the cement mortar solidifies. If the bottom of the box is flush with the external wall, fix the metal mesh on the external wall before plastering the wall. Plastering is not allowed on the bottom plate of the box. The installation disk surface should be flat, the peripheral clearance should be even and symmetrical, the surface (door) should be straight and not skewed, and the screws should be uniformly stressed vertically.
2.4 insulation shaking test:
After all electrical appliances in the distribution box are installed, measure the line insulation with a 500V megohmmeter. The shaking test items include between phase lines, between phase lines and neutral lines, between phase lines and protective grounding lines, and between neutral lines and protective grounding lines. Two people shake the test and make records at the same time, which will be kept as technical data.
C. Quality standards
1, main items:
Grounding protection measures and other safety requirements of low-voltage distribution equipment must meet the construction acceptance specifications.
2. General items:
The distribution box shall be installed in the correct position, with complete components and proper opening (welding and gas cutting are strictly prohibited). Open holes, but hydraulic openers should be used, one hole per tube), and the incision should be neat. The box cover of concealed distribution box clings to the wall; The neutral wire is connected by bus (N-wire terminal) without splicing; The paint is complete, the inside and outside of the tray are clean, the box cover and switch are flexible, the loop number is complete, the wiring is neat, the PE protective ground wire is not installed in series and is obviously firm, and the line section and color conform to the specifications.
D. finished product protection
1. After the distribution box is installed, finished product protection measures should be taken to avoid damaging and soiling electrical appliances and instruments.
2. When installing the box (board) panel (or sticking the face), attention should be paid to protecting the wall clean and tidy.
E. Quality records
1, factory certificate of distribution box and insulated wire products.
2, distribution box installation project preview, self-inspection, mutual inspection records.
3. Design change negotiation records and as-built drawings.
4, electrical insulation resistance test records.
5, electrical lighting appliances and distribution box installation subdivisional work quality inspection and evaluation records.
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