Distribution box (disc) installation project
This chapter applies to the installation of electrical distribution boxes (discs) in buildings.
First, the material requirements
1 Metal Distribution Box (Plate): The box should have a certain mechanical strength, the surrounding smooth without damage, the paint surface without falling off, the thickness of the second floor is not less than 1.5mm, and the flame retardant plastic plate shall not be used as the second floor. All kinds of appliances should be installed firmly, neatly arranged wires, crimped firmly, and product certification.
2 flame-retardant plastic distribution box (disc): The box should have a certain degree of mechanical strength, the surrounding smooth without damage, the thickness of the insulation floor should not be less than 8mm, and a product certification.
3 galvanized materials: angle steel, flat iron, iron sheet, machine screws, wood screws, bolts, washers, round nails, etc.
4 insulated wire: wire specifications must meet the design requirements, and a product certification or "CCC" certification.
5 other materials: electrical instrumentation, fuse (or fuse), terminal board, insulation nozzle, card frame, soft plastic pipe, plastic tape, black tape, anti-rust paint, solder, flux, welding rod, cement, sand.
Second, the main equipment
1 pencil, tape measure, square ruler, level ruler, steel ruler, thread drop, bucket, brush, gray shovel, high stool and so on.
2 hammers, tweezers, hacksaws, saw blades, rasps, flat drop, round burrs, wire strippers, needle nose pliers, crimp pliers, movable wrenches, socket wrenches, hexagonal wrenches, tin pans, tin spoons, etc. .
3 Bench drills, hand drills, drills, wood drills, vise, cases, electric stoves, electrical welding tools, insulated gloves, iron scissors, point punches, megohmmeters, tool bags, tool boxes, bar stools, etc.
Third, the operating conditions
1 Reserve the installation position of the dark assembly box with the civil structure.
2When assembling the surface of the electric box, plastering, spraying, and painting should all be completed.
Fourth, the operating process
(a) process flow:
(II) Installation requirements for distribution box (disc):
1 The distribution box (disc) should be installed in a safe, dry and easy-to-operate place. The bottom end of the distribution box is generally 1.5m away from the ground. In the same building, the height of the same type of disc should be the same, and the allowable deviation is 10mm. .
2 The wooden bricks and iron pieces required for installing the distribution box (pan) should be embedded. All kinds of pre-embedded iron parts should be brushed with antirust paint, and should be clearly and reliably grounded. Hanging distribution box (plate) should be fixed with metal expansion bolts.
3 The metal distribution box (pan) with the appliance door should have obviously reliable bare copper wire grounding.
4 The wiring on the distribution box (disc) must be arranged neatly, bundled into bundles, and clips should be fixed at both ends of the active part. Leads drawn from the surface of the board and the introduced conductors should be left with appropriate margins for ease of maintenance.
5 The conductor shall not damage the wire core or the wire core is too long. The wire pressure head shall be solid and reliable. The multi-strand wire shall not be crimped by the coil. The pressure wire terminal shall be installed with the top wire crimped. The multi-strand wire shall be brushed. After the tin is crimped, the number of wire strands must not be reduced.
6 The various manual controls, control appliances, etc. installed on the panel of the distribution box (disc) shall not be energized (except for special circumstances) when the motor is in the open circuit condition.
7 Electric appliances installed vertically should generally be connected to the power supply at the upper end and connected to the load at the lower end: the loader should be on the left side of the transverse loader (facing the disk surface) and the load on the right side.
8 The power supply indicating lamp on the distribution box (disc) should be connected to the outside of the main switch and should be separately equipped with a fuse (power supply side). The disc brakes shall correspond to the branch roads. Card frames shall be installed below the disc brakes to indicate the type of road and the capacity.
The zero line in the 9TN-C should be grounded repeatedly at the incoming pi box line.
10 Set the neutral (N) and protective earth (PE) busbars on the distribution box (disc) respectively. The neutral conductor and protective earth conductor are distributed through the busbars. Use hexagon socket screws for the crimping points.
11 Magnetically plugged fuses The center exposed screw holes should be filled with insulation to prevent discharge to ground. Magnetic plug insurance shall not expose bare metal screws and should be filled with wax paint or silicone rubber.
12 When the design is not required, when the material used for the PE wire is the same as the phase wire, the cross-section should be selected not less than the values ​​listed in the following table according to the thermal stability requirements.
13 The busbars on the distribution box (disc) should be painted with yellow A-phase (L1), green B-phase (L2), red C-phase (L3), light blue (N-null) and other colors, and the yellow and green bicolor lines are PE line.
14The power distribution box (disc) and the instrument should be firm, flat, clean, evenly spaced, with no loose terminals, flexible opening and closing, and complete components.
15 The distribution box (disc) installation should be firm and flat with an allowable vertical deviation of 1.5 inches.
16 Vertical cabinets shall be installed in special rooms or with fences. The iron fences shall be grounded; the distance from the back wall to walls shall not be less than 800mm (special circumstances according to design); the foundation steel shall be straightened and fixed after being installed, and its horizontal error shall be The meter should be no more than 1mm, and the total length error should not exceed 5mm. The bottom of the floor should not be less than 500mm from the ground.
(III) Positioning of the bullet line: Find the position of the distribution box (disc) according to the design requirements, and locate the line according to the external dimensions of the box (disc); the purpose of the positioning of the bullet line is for the embedded brick or iron piece. You can find the embedded part more accurately, or you can find the position of the metal expansion pipe bolt.
(d) Assembly of electrical boxes (plates):
1 Iron frame fixed distribution box (plate): Straighten the angle steel, measure the size well, draw the sawing line, saw the bending, drill bit, and weld. When it is bent, it is to be squared, and then electric (gas) welding is used to weld the seam tightly, and the buried end is made into a dovetail shape. The rust is removed and the antirust paint is brushed. The iron frame is marked with the high grade cement mortar according to the elevation. The dovetail end is grouted firmly. When burying it, pay attention to the straightness of the iron frame and the distance between the holes. Use the wire drop and level ruler to measure accurately and then stabilize the iron frame. After the cement mortar is solidified, the distribution box can be used. installation.
2 Metal Expansion Bolt Fixing Distribution Box (Plate): Metal expansion bolts can be used to secure the distribution box (pan) on concrete walls or brick walls. The method is to locate the exact fixed point according to the positioning of the bullet line in Article 9.4.3. Use an electric drill or impact drill to drill at the fixed point. The hole diameter should be just buried in the wall of the metal expansion bolt. The hole should be straight and must not be skewed.
(five) The fixing of the distribution box (disc):
1 When the electric box (pan) is mounted on a concrete wall or a brick wall, the dark piping and the dark distribution box and the bright piping are used. If there is a junction box, clean the debris in the box first, then straighten the wires, distinguish the branches and phase sequence, and bundle them into bundles according to the branches. After the box (disc) is positioned, the end of the wire is led to the box, the end of the wire is peeled off, and then the connectors are crimped one by one.
In the meantime, the protective grounding wire and the neutral wire are pressed on the PE busbar and the N busbar, and the box (disc) is adjusted straight and fixed. After installing the panel with more electric tools and meters, you should check whether there are any mistakes with the instrument or not, correct the error, test the power transmission, and fill in the card in the card frame.
2 Reinforce measures shall be taken when fixing the distribution box (pan) on the wooden structure or light steel keel plate wall. If the piping is concealed within the wall of the guard plate and there is a dark junction box, it is required that the box mouth should be flush with the wall surface, and fire prevention treatment should be done at the wooden guard wall. The fire protection paint can be used for protection. In addition to the above requirements, the method of fixation is the same as described above.
3 dark assembly of the fixed box. According to the reserved hole size, firstly find the height and horizontal dimension of the box, fix the box, and then fill the surrounding with cement mortar and smooth it. After the cement mortar is solidified, install the disk and face. If the bottom of the box is flush with the outer wall, plaster the wall after fixing the metal mesh on the outer wall. Do not plaster the tank floor. The installation of the disk surface requires smoothness, the surrounding clearance is even and symmetrical, the face (door) is flat, not skewed, and the screw is subjected to uniform vertical force.
(6) Insulation shaking test:
After the distribution box (disc) is installed, use 1kv megohmmeter to insulate and shake the line. The measurement items include the phase line and the phase line, between the phase line and the neutral line, between the phase line and the ground line, and between the zero line and the ground line. The two were shaken, recorded and included in the technical data file.
V. Quality standards
(a) Master project:
Grounding (zeroing) protective measures and other safety requirements of an appliance must comply with the national construction regulations.2 The cross-sectional area of ​​the conductors on both sides of the pressure contact point in the box is the same; the number of conductors on the same terminal is less than 2, and the parts such as the lock washers are complete.
3 The leakage switch is flexible and reliable, the operating current is not more than 30 mA, and the operating time is not more than 0.1S.
4 Set N line, PE line bus bar, neutral line and protection line are allocated through bus bar. Use hexagon socket screw for pressure line point.
Inspection method: Observe and check the installation record.
(b) General items:
1 The position is correct, the components are complete, the opening of the box is appropriate, the incisions are neat, and the concealed distribution box sticks to the wall (cover) against the wall, the paint is complete, and the interior and exterior are clean.
In the 2 boxes (pans), the wiring is neat, the loop number is complete, the marking is correct, and the PE wire is installed firmly.
There are no flammable materials inside or outside the 3 boxes (pans).Inspection method: observation and inspection.
(3) Permissible deviation items: The allowable deviation of the distribution box (disc) installation verticality is 1.5‰.
Inspection method: hanging wire, check the size.
Sixth, finished product protection
1 After the distribution box (disc) is installed, protective measures shall be taken to prevent damage, dirty electrical equipment and instruments.
2 When installing the box (pan) panel (or face), keep the wall clean.
Seven issues that should be noted
1 The elevation or verticality of the distribution box (disc) exceeds the allowable deviation: due to inaccurate positioning of the measurement or unevenness of the ground, it should be corrected in time.
2 Iron frame not method: Before installing the iron frame, it is not straightened and aligned, or it is caused by the position deviation of the fixed point during installation, and the fixed line is used to re-align and then fixed.
3 The electrical equipment on the plate, the instrument is not firm, flat or uneven, the indenter is not strong, the indenter injure the core, the multi-strand wire indenter is not equipped with the pressure wire terminal, and the card frame is not installed under the brake tool: the screw is not tight Should be tightened, spacing should be adjusted according to the requirements of uniform, find the whole; break the core of the part should be cut off and reconnect, multi-strand wire should be installed on the pressure line terminals, card box should be replenished.
4 The cross-section of the protective earth is not enough, and the protective earth serial connection: it should be corrected according to the specification.
5 wiring arrangement is not neat: should support
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