12 major problems and solutions
First, lightning protection grounding does not meet the requirements
1. Phenomenon
(l) Defects such as slag inclusion, welding, weak welding, biting meat, and insufficient weld seams are found in the lower line, the equalizing ring, and the lightning protection belt.
(2) The welding slag does not knock off, and the welding place on the lightning protection belt does not brush the anti-rust paint.
(3) Rebar is used instead of round steel for reinforced steel.
(4) Directly use the main steel bar welded to the head for lightning protection.
2, the cause analysis
(1) The operator's sense of responsibility is not strong, and the welding technology is not skilled. Most of them are multi-faceted welders in the electrician's class, and the operation skills of the opposite welding are poor.
(2) The on-site construction manager has insufficient implementation of the relevant provisions of the national construction and acceptance specification GB501692 "Grounding device".
3. Preventive measures
(1) Strengthen the skills training for welders, and require that the welds in the lap weld be full and even, especially for the difficult welding such as vertical welding and overhead welding.
(2) Enhance the responsibility of management personnel and welders, timely repair welding unqualified welds, and timely knock out the welding slag and brush anti-rust paint.
(3) According to GB501692 "Code for Construction and Acceptance of Grounding Devices for Installation of Electrical Installations", the connection of the lightning protection down conductor is lap welding, and the lap length is 6 times the diameter of the round steel. Therefore, it is not allowed to replace with the rebar. Round steel is used as a lap joint. In addition, if the main reinforced concrete as the down conductor is welded to the head, the lap joint should be filled in the welded joint.
Second, the outdoor household management pre-treatment does not meet the requirements
1. Phenomenon
(1) Replace the thick-walled steel pipe with a thin-walled copper pipe.
(2) The pre-buried depth is not enough and the position deviation is large.
(3) The corner is welded by electric welding, and the upper wall pipe is connected with the horizontal inlet pipe network to form a 90° angle.
(4) The waterproof treatment of the entrance pipe and the underground outdoor wall is not good.
2, the cause analysis
(1) Material purchasers are not familiar with national norms and standards when purchasing, and some construction units deliberately confuse to reduce costs; construction administrators are not strict or do not dare to object to the contractor’s intentional violations, and do not resolutely implement norms and standards. The supervisor has a loophole in the management of the material entering the site.
(2) Insufficient coordination with civil engineering and other professional teams.
(3) There is no bender or no bender, and the responsibility is not strong. It is easy to use electric welding to bend.
(4) Workers who are buried in the household pipe do not understand the waterproof technology, and do not ask the waterproof professional to help.
3. Preventive measures
(l) The pre-embedded pipe of the household must use thick-walled copper pipe or PVC pipe that meets the requirements (general wall thickness PVCΦl14 is 4.5mm or more, and Φ56 is 3mmm).
(2) Strengthen coordination and cooperation with civil engineering and other related majors, clarify the outdoor ground elevation, and ensure that the buried buried depth is not less than 0.7 meters.
(3) Strengthen the education on the relevant regulations of contract team leaders and material purchasers. Supervisors must strictly implement the requirements for material entry inspection and block the loopholes.
(4) The elbow of the upper wall of the pre-buried steel pipe must be bent with a bender, and welding and welding are not allowed to bend. After the steel pipe is bent, there should be no cracks and significant dents. The bending procedure should not be greater than 10% of the outer diameter of the pipe. The bending radius should not be less than the minimum allowable bending radius of the cable to be penetrated.
(5) Do a waterproof treatment, please contact the waterproof professional on-site or waterproof professional team.
Third, the laying of electric wire tubes (steel pipes, PVC pipes) does not meet the requirements
1. Phenomenon
(1) The cable tubes overlap in multiple layers, and some places are higher than the gluten of the steel bars.
(2) Two or more wires and tubes are placed next to each other.
(3) The depth of the buried wall of the wire and tube is too shallow, even buried in the powder layer outside the wall. The tube showed dead bends, painful folds, and dents.
(4) The wire tube enters the distribution box , and the nozzle is not filled in the box.
The exposure is too long; the nozzle is not flat and the length is different; the nozzle does not need a protective ring; it is not locked and fixed.
(5) When the PVC wire and pipe is pre-buried, the pipe is not blocked by the plug, but the pipe is bent with a clamp.
2, the cause analysis
(1) The construction personnel are unfamiliar with the relevant regulations, and their work attitude is sloppy, and they are convenient and do not follow the regulations. Construction administrator management is not in place.
(2) The architectural design layout and electrical professional coordination are not enough, resulting in multiple conduits passing through the same narrow plane.
3. Preventive measures
(1) Strengthen the quality control of the construction process of on-site construction personnel, and carry out targeted training work for workers; management personnel should be familiar with relevant regulations and strictly manage.
In the common channel. When there are more than 6 sets of towers in each floor, it is recommended that the civil works should be decorated with ceilings in the public corridors, so that most of the entrance lines of the electric professional can enter the household directly through the trunks laid on the ceiling. It is also possible to use a thickened public walkway floor to allow a large number of conduits to be concealed. Electrical professional construction personnel should minimize the number of overlapping layers of the line at the same point.
(3) The wire layers cannot be closely attached to each other. If it is difficult to separate them clearly during construction, they can be separated by small cement blocks.
(4) The electric wire tube is buried in the brick wall, and the distance from the surface should not be 15mm, and the pipe laying should be "horizontal and vertical".
(5) The bending radius (dark burying) of the electric wire pipe should not be less than 10 times of the outer diameter of the pipe. The bending of the pipe should be smooth and smooth with the bending machine or the bristles, and there should be no flat folding or dent.
(6) The wire tube should be leveled into the distribution box, the exposed length is 3-5mm, and the pipe mouth should be sheathed and locked. Enter the wire tube of the floor-standing distribution box, the pipe mouth should be 50-80mm higher than the base surface of the distribution box.
(7) When pre-embedded PVC wire and tube, it is forbidden to use a pliers to flatten and bend the nozzle. Apply a PVC plug that meets the pipe diameter to cover the pipe mouth, and tie it tightly with tape.
Fourth, the wiring, connection quality and color code of the wire do not meet the requirements
1. Phenomenon
(1) The multi-strand wire does not use a copper joint, but is directly formed into a "sheep eye ring" shape, but does not expand tin.
(2) When connecting the terminals of the switch, socket and distribution box, connect several wires to one terminal.
(3) The wire ends are bare, the wires are not arranged neatly, and there is no bundled bandage.
(4) The three-phase, neutral (N-line) and ground-protected (PE line) color code of the wire are inconsistent or confusing.
2, the cause analysis
(1) The construction personnel are not proficient in the wiring process and technology of the wires.
(2) The material purchaser did not prepare the various conductor colors and quantities required for the construction as required, or the construction management personnel mixed them to save materials.
3. Preventive measures
(1) Strengthen the training of construction personnel on standardized learning and skills.
(2) The connection of multiple strands of wire, crimped with galvanized copper joints, try not to make a "sheep eye" shape, if it is done, it should be evenly tinned.
(3) Only one wire connection should be made on the terminal and the terminal block. If two wires are to be connected, a flat gasket should be added in the middle; no more than three connections are allowed.
(4) The wire layout should be horizontal and vertical. When the wire is stripped, the length of each wire should be kept the same. After the wire is inserted into the terminal, there should be no bare conductor; the copper joint and the wire should be wrapped with insulating tape of the same color as the wire.
(5) The material procurement personnel must match the wires of various colors according to the needs of the site.
(6) The construction personnel should clearly distinguish the relationship between the phase line, the neutral line (N line) and the grounding protection line (PE line) and the color mark, ie PA phase - yellow, B phase - green, C phase - red; single phase It is generally preferable to use red; the neutral (N-line) application is light blue or blue; the ground protection line (PC level) must use yellow-green two-color wire.
5. The installation and wiring of the distribution box do not meet the requirements.
1. Phenomenon
(1) There is a gap between the box and the wall, and the box is not straight.
(2) The mortar and debris in the box are not cleaned up.
(3) The opening of the casing does not meet the requirements, especially the use of electric welding or gas welding to open the hole, which seriously damages the paint protective layer of the box and destroys the appearance of the box.
(4) The grounding of the power box is not obvious (below the bottom of the box, it is not easy to find), and the cross section of the repeated grounding wire is not enough. The wire inside the box is bare, the wiring is not neat, and the wire does not leave a margin.
2, the cause analysis
(1) When the cabinet is installed, the coordination with the civil works is not enough, the civil construction joints are not full, and the cabinets are installed without the water level.
(2) Carefully clean the sand debris in the box.
(3) When the "knocking hole" opening of the box does not match the inlet pipe, it must be re-machined by mechanical opening or returned to the manufacturer, or strictly calibrated when ordering, and produced according to the size.
(4) Strengthen inspection and supervision and enhance the responsibility of construction workers.
(5) Thoroughly understand the relevant provisions of the acceptance department regarding grounding. According to the requirements of the power supply department and the municipal quality inspection station, the grounding of the power box and the wires must be clearly exposed, and they cannot be welded or wired under the box. The grounded conductor is in accordance with the specification. When the phase cross section of the device is S≤16mm2, the minimum cross section of the grounding wire is S; when 16<S≤35mm2, the minimum cross section of the grounding wire is 16mm2; when S>35mm2, the minimum cross section of the grounding wire It is S/2.
(6) The wire ends in the box should be unified, not exposed, the wiring should be neat and beautiful, the binding should be fixed, and the wire should have a certain margin. Generally, there should be a 10-5CM margin in the box.
Sixth, the installation and wiring of the switch and socket box and panel do not meet the requirements
1. Phenomenon
(1) The wire box is pre-buried too deep, and the elevation is different; there is a gap between the panel and the wall, and the panel is contaminated with paint and is not straight.
(2) The wire box is left with debris.
(3) The phase line, neutral line and PE protection line of the switch and socket have a series connection phenomenon.
(4) The wire ends of the switches and sockets are bare, the fixing bolts are loose, and the remaining wires in the box are insufficient.
2, the cause analysis
(1) When the pre-embedded wire box is not firmly fixed, the template is expanded and the coordinates are not accurate when installed.
(2) The construction personnel's sense of responsibility is not strong, and they have insufficient understanding of the safety of the use of electrical appliances.
(3) There is an unreasonable civil engineering professional to closely cooperate with the fixed wire box; when the embedded wire box is too deep, a wire box should be installed. When installing the panel, it should be horizontal and vertical, and the level should be adjusted by the level to ensure the uniformity of the installation height. In addition, after installing the panel, it is necessary to fill up the seams, no gaps are allowed, and the panel is cleaned and protected.
(2) Strengthen management supervision and ensure that the phase line, neutral line and PE protection line in the switch and socket cannot be connected in series, first clean the mortar in the box.
(3) Fixed size when stripping, ensure that the thread head is neat and uniform, and the wire head is not exposed after installation; at the same time, in order to firmly press the wire, the single core wire should be twisted into double strands when inserted into the wire hole, tightly tightened with screws.
(4) The wires in the switch and socket box should have a certain margin, generally 100-150mm is appropriate; it is necessary to resolutely put an end to unreasonable material saving.
Seven, the installation of lamps and ceiling fans does not meet the requirements
1. Phenomenon
(1) The lamp position is installed offset, not at the center point.
(2) The horizontality and straightness deviation of the rows of lamps are large.
(3) The chain of fluorescent chains of the chain is not parallel, and the wires that are led are not edited.
(4) The hook of the ceiling fan is processed by rebar, which is poorly formed; the bell jar does not absorb the ceiling, and the junction box is exposed.
(5) The iron plate of the balcony lamp chassis is large and rusty.
(6) The simple light opening of the ceiling of the ceiling is large and not neat.
2, the cause analysis
(1) When the lamp box is embedded, the position is wrong, there is a deviation, and no remedial measures are taken when installing the lamp.
(2) The construction man's curse is not strong, and is not familiar with the current construction and acceptance specifications and quality inspection and evaluation standards.
(3) When the purchaser purchases the lamp, he is willing to make a declaration and ignore the quality;
(4) When the opening of the downlight is not fixed, the size of the nationality and the diameter of the round hole are not uniform.
3. Preventive measures
(1) Before installing the luminaire, you should carefully find the center point and correct the deviation in time.
(2) According to the specification, the deviation of the installation of rows of lamps should not exceed 5mm. Therefore, the positioning of the wires is required during construction, so that the lamps are in the longitudinal, lateral, oblique and main and low levels.
(3) The slings of fluorescent lamps shall be straight to each other, and shall not appear in a splayed shape. The conductors shall be spliced ​​together with the slings.
(4) When the ceiling fan hook is pre-embedded, the galvanized round steel not less than Ф8 is fixed with the steel bar in the plate, and the rebar is not allowed. The hook should be processed and formed uniformly, and the anti-rust paint should be brushed. The bell of the ceiling fan can ceiling and cover the hook and junction box. The rows of ceiling fans should be in a straight line with a deviation of ≤5mm.
(5) The thickness of the bottom box iron plate of the balcony lamp is ≥0.5mm, and the paint surface is even and smooth, which can play a good role in rust prevention; the glass cover should not be too thin to avoid cracking during installation.
(6) The opening of the downlight of the ceiling should be fixed first. In addition to the requirement of straight, neat and equal, the size of the opening should meet the specifications of the downlight, not too large, to ensure that the outer ring is firmly installed when the downlight is installed. Close to the ceiling without gaps.
(7) Construction personnel and procurement personnel must conscientiously implement relevant national and local regulations.
Eight, cable, busbar installation does not meet the requirements
1. Phenomenon
(1) After the cable is installed, there is no unified listing, and the cable is laid in the cable trench and the bridge.
(2) In the shaft, the cable hole is not tightly sealed; the bracket for the vertical fixed cable is too small, too soft, and inclined downward.
(3) The cable is not tightly sealed after passing through the household pipe.
(4) The terminal (the wire ear) is too large or too small, the wall is too thin, and the connector is broken.
(5) The busbar's plug-in box is not installed straight, and the busbars of each section are too long to be transported and installed.
2, the cause analysis
(1) The cable construction units are not well coordinated, and only the cables laid by themselves can be passed.
(2) There is no coordination with the civil construction unit when blocking the strong electric shaft, and the construction personnel do not master the technology of sealing.
(3) The material fails, and the purchaser does not purchase the cable fixing bracket and the terminal (wire ear) according to the standard.
(4) The area reserved for the electrical profession to make strong electric shafts is too small, which makes it difficult to arrange strong electric shafts.
3. Preventive measures
(1) The cable construction team should coordinate well, and arrange the size cables in the direction and position. After installation, use the moisture-proof and anti-corrosion cards to hang out, and indicate the line number, model, specification and starting point of each type of sample cable. . The listing positions are: cable terminal head, corner philosophy, sandwich, both ends of the shaft, and manhole holes in the cable trench.
(2) Use the mixture of hemp and asphalt to block the hole through which the shaft cable passes. When there is an outdoor entrance pipe to the basement, the nozzle should be waterproofed. These work need to be closely coordinated with the civil engineering profession. Clean up the site after blocking.
(3) When purchasing materials such as cable round brackets and terminal blocks (wire ears), purchase them in accordance with the specifications. When crimping the joint, the corresponding hydraulic clamp and corresponding kit are selected accurately.
(4) When ordering busbars, it must be ensured that each busbar should not be larger than each floor; generally not more than 3m, to facilitate the handling and installation in the building.
(5) When the busbars and accessories come into play, it must be strictly in accordance with GBJ149-90 "Code for Construction and Acceptance of Busbar Installations for Electrical Installations" and contract inspection.
(6) When installing the plug-in box, it should be horizontal and vertical, and the contact with the bus bar is reliable and firm.
9. Indoor and outdoor cable trench structures and cable ducts are not in compliance with requirements.
1. Phenomenon
(1) The cable trench and the truss bracket are not straight and easy to break.
(2) Cable trenches and cable ducts are not well drained.
(3) The cable crossing pipe is buried deep enough, and the bell mouth is broken and irregular.
(4) The anti-corrosion and anti-corrosion paint of the steel pipe is uneven, and the sealing property is not enough, especially the anti-rust and anti-corrosion in the pipe are not done.
(5) The grounding pole is not straight and loose in the cable trench, and the grid connection with the bypass pipe is not comprehensive, and some pipes are leak welded.
2, the cause analysis
(1) The civil construction unit is not serious during construction; the truss prefabricated parts are aged or have no steel bars, so that the bearing capacity is insufficient.
(2) There is no certain slope at the bottom of the cable trench, and the water collecting pit is not made according to the specifications; the objective conditions on the site do not meet the drainage requirements.
(3) The construction workers are not responsible for the installation. There are other professional pipes or wells that affect the laying of the cable pipes.
(4) When the tanks are not arranged as required, the poles are welded one by one. When all the pipes are buried and welded, the conditions are not allowed to be welded one by one, and the number of welds is required at the bell mouth.
3. Preventive measures
(1) When installing the truss bracket, the civil engineering unit should draw the line to find the vertical and find the vertical; the distance from the uppermost bracket to the top of the trench is 150mm-200mm, and the distance from the lowest bracket to the bottom of the trench is 50mm-100mm. Qualified ç ¼ brackets should be purchased from qualified manufacturers to ensure sufficient supporting force; steel brackets should be protected against rust and corrosion.
(2) According to the relevant provisions of GB50054-95 "Design Specification for Low-Voltage Power Distribution", the slope of the drainage ditch at the bottom of the cable trench should not be less than 0.5%, and a water collecting pit should be set up, and the accumulated water should be directly discharged into the sewer; For the relevant specifications, you can also refer to Lu Guang's "Atlas of Building Electrical Installation Engineering", Volume 2, Volume 1, 5:35 "General Practice for Cable Manholes". When the puddles are far away from rainwater wells or rainwater wells. When the elevation is higher than the bottom of the cable trench, the corresponding drainage system should be adjusted accordingly. Therefore, the relevant elevation of each major should be carefully compared when the outdoor integrated pipe network diagram is reviewed.
(3) The bell mouth is required to be even and tidy without cracks. When the cable tube is pre-buried, the depth should be less than 0.7m. If the objective conditions are not met, the pipe should be covered with cement mortar to ensure that the pipe is not crushed.
(4) Thick-walled copper pipes should be used for cable pipes. Both internal and external should be coated with anti-corrosion anti-rust paint or asphalt. The paint surface should be even; especially at the welded joints, it needs to be treated with anti-rust. When the two cable tubes are butted, the inner nozzles should be aligned, and then the short sleeves (length not less than 2.2 times the outer diameter of the cable tubes) should be added and welded firmly and sealingly.
(5) The grounding shoulder steel in the cable trench should be installed firmly. Generally, a fixed terminal is installed every 0.5-1.5m, and the height of the high groove bottom is 250mm-300mm. When passing through the pipe, it must be overlapped with each steel pipe, and the lap joint should be treated with anti-corrosion and anti-rust treatment. In order to ensure that each steel pipe can be reliably connected with the grounding pole, it is welded one by one when the pipe is buried, and it is not allowed to be welded after the pipe is buried.
10. Installation of street lamps, lawn lamps, garden lamps and floor lamps does not meet the requirements.
1. Phenomenon
(1) The lamp post is painted, rusted, and loose.
(2) The grounding installation does not meet the requirements, even without a grounding wire.
(3) The lampshade is too thin and is easy to break or fall off.
(4) The number of wattages of the lawn lamp and the floor lamp is too large. When the lampshade is used, the temperature of the lampshade is too high, which is easy to burn people; or the corner of the lampshade is sharp and easy to cut.
2, the cause analysis
(1) There is no strict requirement when purchasing the lamp; the anti-rust layer is not well prepared; the glass or plastic of the lamp cover is not strong enough; the bolts of the fixed lamp holder do not match and are difficult to fix.
(2) The design only considers the illuminance, and negligence may cause harm to pedestrians, especially children.
(3) The construction personnel do not conscientiously implement the specifications and have insufficient understanding of the importance of grounding to personal safety.
3. Preventive measures
(1) Select qualified lamps, especially for the coastal wet weather in our city, we must use better anti-rust lamp poles; the lampshade should have strong anti-typhoon strength whether it is plastic or glass.
(2) Lawn lights and ground lights generally pursue the effect of embellishment, and the influence of the temperature generated by high-power incandescent should be considered in the design and selection. The relevant data shows that the surface temperature of the 40W lamp can reach 563 °C, 60W can reach 137-180 °C, and 100w can reach 170-216 °C. Therefore, install 60W in low ground and protective cover narrow lamp and lawn lamp. The above bulbs can easily cause the temperature of the protective cover to be too high and burn people. In addition, some lawn lights have been selected several times in order to select chic, the corners are too sharp, and it is easy to hurt children who like to touch.
(3) Grounding is a matter of life. Street lamps, lawn lamps, garden lamps and floor lamps must have good grounding; the grounding pole of the pole must be welded firmly, the joint is tinned, and the PE protection line of the street lamp power supply is connected with the pole grounding report. The spring washer must be used to crimp the top and then the nut.
XI. Telephone and TV system wiring and panel wiring do not meet the requirements
1. Phenomenon
(1) A number of telephone lines are bundled and fixed in the weak electric shaft of the high-rise building, which is messy.
(2) The number of the wire box of the DP box is not obvious, and the numbered cards are resurgence, and the font is difficult to distinguish.
(3) The telephone socket wiring is loose, and the telephone sound quality is distorted.
(4) The TV antenna damages the shielding layer and the TV audio and video is distorted.
(5) The dirty wall surface during the construction, the cleaning site was not cleaned after the completion of the construction.
2, the cause analysis
The entry time is relatively late. As a professional team, from the possession of the site conditions to the prevention of the wiring being stolen, the TV and TV teams usually enter the game late. At this time, the wall of the civil construction often completes the painting process, so they are easy to construct during construction. Soil the wall.
3. Preventive measures
(1) Strengthen the management of construction personnel, closely cooperate with the civil engineering profession, clean the site after construction and installation, and keep the floor and wall clean.
(2) When multiple telephone lines are laid in the weak electric shaft, bundle them into bundles, and require that the trunking cover be fixed in the trunk line every 1.5 meters.
(3) The telephone line connector should be connected with moisture-proof wiring connector and clamped with wire clamp; the telephone socket should be carefully tightened with screws, and the wire should be tightened and the wiring should not be broken (the telephone core is small).
(4) The telephone lines in the DP box should be neatly arranged. The line head of each telephone line is marked with a moisture-proof line card to indicate the circuit and the room number, so as to facilitate future telephone installation.
(5) The shielding layer of the TV antenna is easy to be scratched by the hard object when the tube is worn. Therefore, the tube should be cleaned before threading, and the tube should be smoothed and carefully pulled when threading, so as not to damage the shielding layer and ensure the TV image. The sound quality is clear.
12. The installation of the probe for fire protection and intelligent systems does not meet the requirements.
1. Phenomenon
(1) The probe is loosely installed, and there is a gap between the wall, the board and the ceiling.
(2) The probe and the lamp are too close together, and the heat of the lamp affects the sensitivity of the probe.
2, the cause analysis
(1) The construction personnel did not carefully level and fix the probe base.
(2) The installation plane is narrow, and the distance between the probe and the lamp is not leveled when the tube box is pre-embedded.
3. Preventive measures
(1) Enhance the responsibility of the construction personnel. When installing the base, be sure to level with the pole and wall. Pay attention to tightening when installing the probe.
(2) Under normal circumstances, the smallpox area of ​​the bathroom is small, which tends to make the lamp and the smart probe too close. At this time, the center point of the lamp and the distance of the probe from the window should be properly adjusted to ensure that the distance between the two is about 50CM. The fire-fighting probe on the top of the public walkway ceiling should be kept at a distance of 50 cm from the luminaire when the cable box is embedded (the luminaire is guaranteed to be at the center position).
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