1 analysis and prevention of common quality problems in electrical engineering
1. 1 The installation wiring of switch, socket box and panel does not meet the requirements.
Phenomenon: the box is embedded too deeply, the elevation is different, there is a gap between the panel and the wall, and the panel is polluted by glue paint and is not straight; There are mortar sundries in the box; Phase line, zero line and PE protection line of switch and socket are connected in series; The wire ends of switches and sockets are exposed, the fixing bolts are loose, and the wire allowance in the box is insufficient.
Cause analysis: the wire box is not fixed firmly when embedded, the template expands, and the coordinates are not accurate when installed; Construction personnel have a weak sense of responsibility, lack of understanding of the importance of using electrical appliances, and covet convenience; There is an unreasonable idea of saving materials.
1.2 outdoor water inlet pipe pretreatment does not meet the requirements.
Phenomenon: thin-walled copper pipes are used instead of thick-walled steel pipes; The buried depth is not enough, and the position deviation is large; The elbow is bent by electric welding, and the upper wall pipe is connected with the horizontal household pipe network at 90 degrees by electric welding; The entrance pipeline and basement exterior wall are not well waterproof.
Cause analysis: material buyers are not familiar with national norms and standards when purchasing, and some construction units deliberately confuse them to reduce costs; The construction manager is not strict with the control or dare not raise objections to the contractor's intentional violation of regulations, and does not resolutely implement the norms and standards; There are loopholes in the management of material input by the supervisor; Insufficient coordination with civil engineering and other professional teams; There is no pipe bender or can't use a pipe bender, so the sense of responsibility is not strong, and it is convenient to use electric welding to hot bend; Workers embedded in household pipes don't know waterproof technology and don't ask waterproof professionals for help.
Precautions: Thick-walled copper pipes or qualified PVC pipes must be used for embedded pipes in the house (generally, the wall thickness of PVC φ 1 14 is greater than 4.5mm, and φ 56 is 3 mm); Strengthen coordination with civil engineering and other related majors, make clear the elevation of outdoor floor, and ensure that the buried depth of embedded pipes is not less than 0.7m；; Strengthen the education of relevant laws and regulations for contract team leaders and material buyers, and the supervisors should strictly implement the regulations that materials need to be inspected when entering the site to plug the loopholes; The elbow of the upper wall of the embedded steel pipe must be bent by a pipe bender, and welding and welding bending are not allowed; Do a good job in waterproof treatment, and ask waterproof professionals to give on-site guidance or waterproof professional teams to do waterproof treatment.
1.3 The wiring, connection quality and color code of the conductor do not meet the requirements.
Phenomenon: Multi-strand wires are made into a "sheep's eye" shape without copper joints, but Wuxi swells; When connecting the terminals of switches, sockets and distribution boxes, several wires are connected to one terminal; The thread ends are exposed, the wires are irregularly arranged, and there is no binding and dressing; The color codes of three-phase conductor, neutral line (N line) and grounding protection line (PE line) are inconsistent or confused.
Cause analysis: the construction personnel did not master the wiring technology and technology of wires skillfully; The material buyer did not prepare all kinds of conductor colors and quantities required for construction as required, or the construction management personnel mixed them to save materials.
Preventive measures: strengthen the standard study and skill training of construction personnel; For the connection of multi-strand wires, galvanized copper joints should be used for crimping, and the "sheep eye" shape should be avoided as far as possible. If it is done, it should be evenly tinned; Only 1 wires should be connected to the posts and terminals. If two wires need to be connected, a flat pad should be added in the middle. No more than 3 connections are allowed; The conductor layout should be horizontal and vertical, and the length of each conductor should be the same when stripping the conductor, and there should be no bare core after the conductor is inserted into the terminal; The joint between the copper joint and the conductor shall be wrapped with insulating tape with the same color as the conductor; Material procurement personnel must be equipped with wires of various colors according to the needs of the site; Construction personnel should clearly distinguish the functions of phase line, zero line (N line) and grounding protection line (PE line) from the color code, that is, PA phase-yellow, B phase-green and C phase-red; Generally, red should be used for single phase; The zero line (N line) should be light blue or blue; Grounding protection wire (PC level) must use yellow-green double-color conductor.
1.4 The installation and wiring of switch, socket box and panel do not meet the requirements.
Phenomenon: the box is embedded too deeply and the elevation is different; There is a gap between the panel and the wall, and the panel is polluted by glue paint and is not straight; There are mortar sundries in the box; Phase line, zero line and PE protection line of switch and socket are connected in series; The wire ends of switches and sockets are exposed, the fixing bolts are loose, and the wire allowance in the box is insufficient.
Cause analysis: the wire box is not fixed firmly when embedded, the template expands, and the coordinates are not accurate when installed; Construction personnel have a weak sense of responsibility, lack of understanding of the importance of the use of electrical appliances, and covet convenience.
Preventive measures: work closely with civil engineering specialty to fix the box accurately and firmly; When the embedded box is too deep, it should be boxed; After the panel is installed, it should be fully patched and no gaps are allowed, so the panel should be cleaned and protected. Strengthen management and supervision to ensure that the phase line, zero line and PE protection line in the switch and socket cannot be connected in series, and clean the mortar in the box first; When demoulding, the size is fixed to ensure that the thread end is neat and consistent, and the thread end is not exposed after installation; At the same time, in order to firmly compress the wire, the single-core wire should be twisted into two strands when inserted into the wire hole, and tightened with screws. The wires in the switch and socket box should have a certain margin, generally 100 ~ 150 mm is appropriate.
1.5 the installation of lamps and ceiling fans does not meet the requirements.
Phenomenon: the lamp position is installed eccentrically, not at the center point; The deviation between levelness and straightness of lamps in rows is large; The chains of chained fluorescent lamps are not parallel; The ceiling fan hook is made of rebar, which is not well formed; The lampshade does not absorb the ceiling, and the junction box is exposed; The balcony lamp chassis is large and rusty; The opening of the simple lamp on the ceiling is too large and irregular.
Cause analysis: the position of light box was wrong when embedded, and there was deviation, and no remedial measures were taken when installing lamps; Construction personnel have a weak sense of responsibility and are not familiar with the current construction and acceptance specifications and quality inspection and evaluation standards; Buyers buy lamps regardless of quality; The size of the downlight is not fixed when it is turned on, and the diameter of the round hole is uneven.
Precautions: Before installing lamps, carefully determine the center point and correct the deviation in time; According to the specification requirements, the installation deviation of rows of lamps and lanterns should not be greater than 5 mm; When the ceiling fan hook is embedded, galvanized round steel not less than Ф 8 shall be fixed with the steel bars in the plate, and rebar shall not be used; Rows of ceiling fans should be in a straight line with a deviation of 5 mm or less; The thickness of iron plate at the bottom box of balcony lamps is ≥ 0.5 mm; The glass cover should not be too thin to avoid cracking during installation; First set the coordinates of the opening of the ceiling downlight, and the outer ring should be firmly attached to the ceiling when installing, so as not to expose cracks; Construction personnel and procurement personnel should conscientiously implement the relevant national and local norms.
2. The influence of common electrical quality problems on the main civil engineering
2. 1 affecting civil structures
Common electrical quality problems directly affect the stress distribution of load-bearing walls, stair beams and ring beams, and even destroy the main structure. For example, in order to fix a chandelier on the ceiling, a wooden brick needs to be placed from top to bottom at the joint of the floor. However, due to the improper construction sequence or the size of wooden bricks, two hollow slabs with wooden bricks were smashed and exposed, which destroyed the main reinforcement structure of hollow slabs and caused great harm to the whole main structure. Another example is that the distribution box is reserved on the load-bearing wall under the stair beam, and the local bearing capacity of the load-bearing wall is not enough to bear the weight of the stairs above, which forms a serious hidden danger.
2.2 affect the appearance and function of the wall.
Buried pipes with grooves destroy the flatness of the wall and affect the appearance of the wall. Improper pre-embedded junction box, uneven socket and improper switch installation position have seriously affected the use function, causing inconvenience to residents, which is far from the original intention of designers.
2.3 Not easy to maintain and repair
In electrical construction, there are some common quality problems, such as unqualified wires, not using figure-eight connection, and blocked junction boxes, which affect the normal electricity consumption of residents and bring a lot of trouble to maintenance and overhaul. For example, after the indoor decoration is completed and used for a period of time, the conductor breaks in the wall and the junction box cannot be found, which is a difficult line obstacle to deal with. To restore power supply, it is bound to destroy the decorated walls or indoor lighting, and bring unnecessary trouble to residents.
3 electrical quality common fault causes
3. 1 The technical quality of personnel engaged in electrical installation is poor.
Some don't have the certificate of electrician special type of work, and some hire temporary workers to participate in electrical installation. They don't understand the design drawings deeply, or even understand them, and they simply don't have the technical ability to undertake electrical installation projects. Among other contractors, the management of personnel engaged in electrical installation engineering is not enough, so it is managed by civil construction personnel. As a result, it often becomes a substitute and cannot meet the quality requirements of electrical installation engineering.
3.2 Electrical materials market chaos, lax control.
Many projects are privately contracted. Driven by interests, a large number of unqualified materials are used in the project, which seriously affects the quality of the project.
3.3 Construction enterprises pay insufficient attention to the quality of electrical installation.
The internal quality assurance system of enterprises often "pays more attention to the main body than the installation" and ignores the installation link. The construction site is not equipped with full-time electrical quality inspectors, the management is out of control, the construction personnel lack professional and technical training, even take up their posts without a license, are unfamiliar with norms and standards, blindly construct, and do not conduct self-inspection or self-inspection is a mere formality.
3.4 civil engineering, electrical two professional cooperation is not enough
Civil construction workers do not cooperate with electricians to complete the reserved process according to the design requirements, which leads to many distribution boxes being squeezed up and down and twisted, the switch is too far away from the door, and the socket in a room is not in a horizontal line, which is not beautiful and can not achieve the use function, which brings many difficulties to installation and use.
4 Measures and suggestions
4. 1 First of all, we should raise our awareness ideologically.
The electrical installation project should be paid enough attention by the owners, contractors and contractors, and regarded as an indispensable sub-project in residential construction, so as to improve the technical and professional quality of electrical management and installation personnel and enhance their sense of post responsibility.
4.2 Improve the design level of residential electrical installation
Designers should pay more attention to aesthetics, decorative effect and use function on the premise of satisfying the conventional power supply and ensuring the safe use of electricity, so as to meet the needs of residents' modern life with aesthetics, convenience, comfort and safety, and raise the electrical installation project to a new level.
4.3 Strengthen management and improve the quality assurance system
Whether the qualifications of the design, construction and supervision parties of the project construction are suitable for the projects undertaken by them is the premise to ensure the quality of the project, and it is also the basic requirement of the Building Law and other relevant laws and regulations. Therefore, the quality supervisor should review the qualification grade of relevant units before the project starts, and also review the production license qualification of relevant materials and equipment manufacturers.
4.4 raw materials enter the site and control the quality of materials.
First of all, we must strictly control the purchase channels, and all electrical materials, electrical appliances and equipment should be purchased from formal commercial channels; Secondly, it is necessary to strictly implement the acceptance system and check the factory inspection reports and product certificates of all kinds of materials and equipment that enter the site. Electrical products subject to compulsory license management by the state must obtain safety certification and conduct necessary sampling inspection to ensure that the models, specifications and quality and performance indicators of all kinds of materials and equipment that enter the site meet the requirements of design and relevant national product quality standards.
4.5 Strictly check the acceptance of electrical installation works.
The acceptance contents include: threading and wiring of electrical appliances, pipelines and fixed materials, wire connection and terminal connection, grounding wire connection, grounding electrode embedding, lightning protection network embedding, down lead connection, strict insulation and grounding test, etc. These divisions, subdivisional works and materials used must be inspected one by one in strict accordance with the design requirements, and those that do not meet the design requirements and specifications will be resolutely rejected.
5 concluding remarks
With the improvement of people's living standards, the requirements for electrical installation engineering are getting higher and higher. It should not only meet the needs of lighting, household appliances and safe electricity use, but also pay attention to its beautiful, applicable and convenient use effect. The quality of building electrical installation engineering is an important factor that directly affects the quality of residential engineering. These problems cannot be ignored. Before construction, we must find out the causes of quality problems, formulate practical preventive measures, and nip quality problems in the bud. This puts forward higher requirements for the designers and constructors of electrical installation project, and puts electrical installation project in the same important position as civil engineering, pays special attention to the quality management of electrical installation project, and makes the electrical installation project develop in the direction of applicability, reliability, economy, beauty and convenience.
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