What does electrician mean?

Electrician refers to the science and technology that studies the objective law and its application in electromagnetic field, as well as the two industrial production systems of electric power production and electrician manufacturing.

First, electrician common sense

1. Before decoration, there must be (strong current and weak current) construction drawings, and electrical engineering completion drawings shall be provided upon completion.

2, electrical installation construction personnel should hold relevant certificates.

3, wiring should be color separation, phase line (L) color should be unified, zero line (N) should be black, protection line (PE) must be yellow and green.

4, plastic wire protection tube and junction box appearance should not be damaged and deformed.

5. Generally, the pipes are 4 branches (DN 15) and 6 branches (DN20). The wall thickness of smooth pipes is 2 .0 0.3mm, and there are no more than 4 threads.

6. Ordinary appliances are equipped with 2.5mm2 copper wire. High-power electrical appliances such as air conditioners should be equipped with 4mm2 or 6mm2 copper conductors.

7, high voltage lines and weak current lines are prohibited to wear in the same casing.

8, the same indoor power supply, telephone, television and other sockets should be at the same level elevation, the height difference should be less than 5 mm. ..

9. When installing lamps and lanterns, all design and installation fixing points of lamps and lanterns must be fixed.

10. Installation of the junction box in the ceiling: the junction box shall be located at any position where leads and wiring are required. And shall not be fixed on the wooden keel, should be fixed at the top.

1 1, when the downlight needs to be opened, the position of the main keel should be verified to avoid cutting and damaging the keel.

12, lighting lamps and lanterns should be equipped with separate switches, and the lamps of each lighting circuit should not exceed 2KW (excluding lanterns), and the combined lamps can be controlled in groups.

13, when the ordinary chandelier uses the cord itself as the suspension. Only applicable to lamps with mass lower than 1kg. For lamps above 1kg, the hanging chain must be used, and the flexible cord is not stressed.

14. Determine the pipeline direction, elevation and switch according to the position of electrical equipment. Before slotting, mark the position of socket and locate it.

The depth of the wall (ground) groove shall ensure that the concealed pipeline is not exposed after repair and does not damage the stressed steel bar.

15. When the pipeline length exceeds 15 m or there are two right-angle bends, cable boxes should be added.

16, lines with different voltages, different circuits and different signals are strictly prohibited to be set in the same tube. Wires in the same circuit should be inserted into the same pipe.

17, grounding protection must be in place, and shall not be misplaced or omitted from the zero line.

18, the pipeline in the ceiling should be fixed at the top with a line card, and the junction box should be fixed with a wooden wedge and nails. Shall not be placed on the keel or fixed on the derrick without fixed measures.

19, the opening of the threading pipe and the junction box are fixed with lock nuts, and frontal approach is prohibited. The threading tube is not easy to fall off, the wire is easy to pull, and the insulation layer is not damaged.

20. Where water is used in kitchens, bathrooms, laundry rooms, etc., threading pipes and accessories are connected with special glue, which is tightly sealed, and no water can enter.

2 1, the wire connection can be soldered or tinned after crimping with crimping cap, which is not suitable for splicing. Temporary splicing must be wrapped with tape. If the crimping conditions are not met, the splicing place must be wrapped with high-pressure waterproof tape.

22. When using armored cord, the connection part should be brushed with tin.

23. Sockets and switch panels are strictly prohibited near the bathing area 1000㎜.

24. When Yuba is installed, the wooden keel of the fixed frame must be coated with fire retardant paint. Special accessories are used for lifting points.

25. Where is the circuit arranged to wear hoses and hard pipes? Except for the wall top structure that does not have the conditions to wear hard pipes, all circuit reconstruction parts need PVC flame-retardant hard pipes. Only in the part where the lamp position needs to be connected, it is allowed to wear PVC flame-retardant hose, and its length shall not be greater than1000 mm.

26, light steel keel gypsum board partition pipe, horizontal cloth pipe can pass through the keel, need to turn vertically, must knock down the hole on the keel or punch separately.

27. The junction box and threading tube must be made of the same material. The use of iron pipes and iron junction boxes must be bridged.

28. When installing spotlights, the guide rails and brackets must be attached tightly, and the lamp holder is seamless with the top surface.

29. When the light bulb power is below 100W, you can use a plastic lamp holder. The lamps above 100W and moisture-proof enclosed lamps should use porcelain lamp holders.

30. When the fluorescent lamp is hidden, the position of its accessories should be easy to maintain.

3 1, if the ground wiring is not carried out at the same time as the floor tile or floor tile laying, the wiring pipeline must be protected with cement to prevent the pipeline from being fractured.

32. When installing lighting appliances on brick-concrete structures, embedded hooks, expansion bolts, nylon expansion pipes or plastic expansion pipes should be used for fixing, and wooden wedges are strictly prohibited.

33, when the chandelier lamps and lanterns weight is greater than 3kg, embedded hook or bolt should be adopted. The bearing capacity of fixing parts should match the weight of electric lighting appliances, and the connection with the structural surface must be firm.

34, lamps and lanterns shall not be directly installed on combustible components.

35, wire, telephone, TV connector must use professional connector card.

36. When starting work, remove all switches and sockets, and protect all screws and nuts. The thread ends are wrapped with adhesive tape and then plugged back to facilitate coating construction.

37, strong and weak current can't mix tube or borrow box transition.

38, metope wiring need to slot, slot size uniform, consistent depth.

39, wire in the tube should not have joint and kink, joint should be located in the junction box.

40, the construction personnel shall not modify the TV recording system, should let the customer please related professionals to modify.

4 1. After other decoration is completed, the electrician construction personnel will install the electrical switch and panel. Prior to this, after the power test, the wire ends were wrapped with insulating tape, and then various installations were carried out after the completion.

42, all kinds of junction boxes, sockets, there should be no gaps around the panel, the cover plate should be correct, installed firmly, close to the wall, the panel is pollution-free, clean and tidy.

43, water pipes and metope must be fixed firmly, firmly. One fixed card every 60cm.

44, wire in the ceiling can't disorderly pull the place, after piping, its direction should be according to the Ming piping, be horizontal and vertical, in the junction box of piping or the corner on both sides should be set symmetrical hanging bracket fixed wire tube, or use a line card to fix the piping at the top, under the junction box can also be punched wedge, fixed with nails. Shall not be placed on the keel or fixed on the derrick without fixed measures.

45, wire in the junction box should have a certain margin, generally it is advisable to have a 200mm length margin.

Second, the electrical instrument

principle of operation

The basic working principle of the electric indicator is to convert the measured electric quantity or non-electric quantity into the deflection angular displacement of the movable part of the indicator. The measured can not be directly added to the measuring mechanism, and it is generally necessary to convert the measured into a transition quantity that can be measured by the measuring mechanism. This part which is converted into transition quantity by measurement is called measuring circuit. The mechanism that converts the transition quantity into deflection angle according to a certain relationship is called measuring mechanism. The measuring mechanism consists of a movable part and a fixed part, which is the core of the instrument. Electric indicating instrument is generally composed of measuring circuit and measuring mechanism.

The main function of the measuring mechanism is to generate the rotating torque that deflects the indicator of the instrument, as well as the reaction torque and damping torque that make the indicator keep balance and stability quickly.

When the measuring circuit converts the measured electric quantity or non-electric quantity into the electric quantity that can be directly measured by the measuring mechanism, the movable part of the measuring mechanism deflects under the action of the deflection torque. At the same time, the reaction moment generated by the part of the measuring mechanism that generates the reaction moment also acts on the movable part. When the rotational moment is equal to the reaction moment, the movable part stops. Because the movable part has inertia, it can't stop quickly when it reaches equilibrium, but swings back and forth near the equilibrium position. The damping torque generated by the damping device in the measuring mechanism makes the pointer quickly stop at the equilibrium position and point out the measured size, which is the basic working principle of the electrician indicating instrument.

classify

There are many kinds of electrical measuring and indicating instruments, and their classification methods are also varied. Understanding the classification of electrical depth indicators is helpful to understand their characteristics and the general situation of electrical gold measurement indicators.

The following introduces the classification methods of several commonly used electrical measuring and indicating instruments.

(1) is divided into magnetoelectric system, electromagnetic system, induction system, electrostatic system and so on according to the working principle.

(2) There are ammeters (ammeters, milliammeters and microamperes), voltmeters (voltmeter and millivoltmeter), power meters, watt-hour meters, power factor meters, frequency meters, megohmmeters and other multimeters, such as multimeters.

(3) According to the type of current to be measured, there are DC meters, AC meters and AC /DC meters.

(4) According to the mode of use, there are switch-type and portable instruments. Switchboard instruments are usually fixed to switchboards or equipment. 7. The general error is large and the price is low, which is suitable for general industrial measurement. Portable instrument has small error (high precision) and high price, which is suitable for laboratory application.

(5) According to the accuracy of the instrument, it is divided into seven grades: 0. 1, 0.2, 0.5, 1.0, 1.5, 2.5, 5.0 * *.

In addition, according to the defense ability of the instrument to electromagnetic field, it is divided into four grades: I, II, III and IV. According to the use conditions of the instrument, it is divided into three groups: A, B and C.

mistake

There is always a certain difference between the measured results of various electric measuring instruments and the measured actual values, which is called instrument error. The error value reflects the accuracy of the instrument itself.

(A) instrument error classification

1. Basic error

Under normal working conditions, the error caused by the imperfection of instrument structure and manufacturing process is called basic error, which is the inherent error of instrument.

2. Additional error

The additional error is caused by the change of working conditions (temperature, placement mode, frequency, external electric field, external magnetic field, etc.). ).

(2) Wrong representation

There are three forms of instrument error: absolute error, relative error and citation error.

1. Absolute error

The indicated value Ax of the instrument and the measured actual value 4. The difference between them is called absolute error.

2. Relative error

The percentage of the absolute error a to the measured actual value is called relative error.

3. Wrong reference

The relative error of each instrument at each point in the measuring range is different. In engineering, the citation error is used to reflect the accuracy of the instrument.

Third, the safety regulations

I. Equipment installation

(1) When installing high-pressure oil switch, automatic air switch and other switch devices with spring back, the switch should be placed in the off position.

Electrician installation

Electrician installation

(2) When handling the power distribution cabinet, there should be special personnel to command and keep synchronization. When installing multiple switchboards (boxes) in parallel, fingers shall not be placed at the joint of two switchboards (boxes), and connecting screw holes and screws shall not be touched.

(3) Electrical equipment used in the open air should have good rain-proof performance or reliable rain-proof facilities. The distribution box must be firm, complete and tight. It is forbidden to place sundries in the distribution box in use.

(4) When gouging and drilling, you must wear protective glasses, and the hammer handle shall not be loose. Chisels should not curl or crack. When hitting the wall and floor with eyes, no one is allowed to go near the back of the wall or under the floor.

Second, the internal installation

(1) When installing the lighting circuit, it is not allowed to walk or pile materials directly on the batten ceiling or sound insulation board; When walking due to homework, scaffolding must be laid on the big stare blankly wall; 36V low-voltage power supply should be used for lighting in the ceiling.

(2) When working on the scaffold, the scaffold must be paved, and there can be no gaps and probe plates. The materials used should be put into the tool bag and carried with you. Don't throw them around.

(3) When bending on the platform and floor with a human pipe bender, keep your back to the center of the building, and avoid the face when operating. When filling large-diameter pipes and simmering pipes with sand, the sand must be dried with fire before filling. When using mechanical percussion, no one is allowed to stand below, and manual percussion should be staggered up and down. No one can stay in front of the nozzle when the pipe is heated.

(4) When the pipeline passes through the belt line, it is not allowed to make a phone call or blow at the nozzle to prevent the belt line from popping up. When two people thread, they should cooperate and coordinate. Thread high, don't push too hard.

(5) When laying the steel wire rope hanging pipe, the steel wire rope head should be prevented from being punctured. Tighten the steel cable with moderate force to prevent the hanging basket bolt from breaking.

(6) When using casing machine, electric grinding wheel, bench drill and hand electric drill, ensure good insulation and reliable neutral grounding. The leakage protection device is sensitive and effective.

Third, the perimeter installation

(1) Before operation, check tools (milling, pickaxe, hammer, brazing, etc. ) solid and reliable. When digging a pit, slope should be placed according to soil quality and depth.

(2) Traffic arteries or places where people often pass through should be covered in time, and red lights should be set at night to warn them. When the chassis is transported down to into the pit, it is necessary to prevent hands and feet.

(3) When handling poles at the construction site, there should be special personnel to command them. When transporting cars, they must be tied firmly to prevent rolling. When people lift it, they should echo back and forth and coordinate, and the pole should not be too high from the ground to prevent one side from spraining.

(4) When climbing the pole manually, there should be someone to command it. Check whether the tools are firm and reliable before poling (e.g. the fork wood is free of scars, the chain is suitable, and the sliding rope, horizontal rope and steel rope are free of scars). The ground anchor drill should be firm and reliable, and the rope should be applied evenly in all directions. When operating, cooperate with each other, obey the command and balance the strength; No one is allowed to stand under the mechanical upright post and jib, and all live lines above (within the rotating radius of jib) must be cut off.

(5) When the pole moves in place, no one is allowed in the pit. After the pole is erected, the fork wood must be erected before the hook can be removed. Before the pole pit is filled, the fork wood, sliding rope or horizontal rope shall not be removed.

(6) The diameter of the pole tip shall not be less than 13cm, and the buried depth shall be110 plus 0.6m The wooden pole shall not be split or decayed, and the root shall be brushed with asphalt for anticorrosion. Cement rods shall not be exposed, cracked or twisted in the circumferential direction.

(7) When assembling the cross arm on the pole, the opening of the trap plate should be appropriate, and the force should not be too strong.

(8) When working on a pole, it is forbidden to throw materials up and down. Tools should be put in the tool bag, and the small rope for transferring tools up and down should be firm and reliable. After handing over the tools, stay 3 meters away from the pole.

(9) Tighten the rod horizontally and tighten the clamping bolt. When the bent conductor is tightened, the operator should work outdoors. Temporary pedal bracket installed in tight line mode shall be firm. If a bamboo ladder is used, the ladder must be tied with a rope. When adjusting the cable, no one is allowed on the pole.

(10) The lead (iron) wire or steel wire rope used to tighten the rope should be able to withstand all tensile forces and must be firmly connected with the steel wire. No one can be under the conductor when the conductor is tightened. When the terminal is tight, temporary stay wires should be set in the opposite direction.

(1 1) When stringing, a temporary grounding wire should be set up every 2-3 kilometers on the line, which must be removed before power transmission. Stop climbing poles in the days of heavy rain, heavy snow and gale above level 6.

Fourth, the cable installation

(1) The ground on which the cable shaft is installed must be level. The bracket must be a special bracket with a bottom plane, and it shall not be replaced by a jack. Cable laying must be carried out in accordance with the content of safety technical measures disclosure, and designated personnel command.

(2) When pulling the cable manually, the strength should be even and the speed should be steady, and it is not allowed to jerk and run. People who look at the shaft must not stand in front of the cable shaft. When laying cables, people at corners must stand outside the bending radius of cables. Personnel passing through the pipeline must ensure that their hands are not too close to the nozzle when sending cables; When encountering cables, eyes and body are strictly forbidden to directly face the nozzle.

(3) When laying cables vertically, there must be safety measures to prevent cables from slipping out of control. After the cable is put away, it should be fixed and fastened immediately.

(4) When winding the cable manually, the shaft pusher shall not stand in front of the cable, and their positions shall not exceed the center of the cable shaft. When the cable goes up and down the slope, the iron pipe should be inserted into the central hole of the cable shaft and the rope should be tied to the iron pipe to advance smoothly and slowly. When the cable stops, tighten the cable and brake in time. The gradient of human rolling cable duct shall not exceed 15.

(5) When transporting cables by car, the cables should be placed in front of the front of the car as far as possible (people who follow the car must stand behind the cables) and fixed with wire ropes.

(6) When laying cables in the trench of the electrified distribution room, the switch cabinet where the cables enter must be cut off. And measures such as insulating clapboard should be adopted. When operating beside the switchgear, the safety distance should not be less than1m (switchgear below10kV). If the cable remains for a long time after laying, it must be tied and fixed or measures must be taken. It is forbidden for cables to contact charged bodies.

(7) When digging cable trench, slope should be placed according to soil quality and depth. When constructing cable trenches near traffic lanes or busy areas, railings and signs should be set up, and red sign lights should be set up at night.

(8) When laying cables in tunnels, the temporary lighting voltage shall not be greater than 36V. Before construction, the ground should be cleaned to drain the accumulated water.

V. Electrical debugging

(1) The metal shell of the withstand voltage test device must be grounded. If the two ends of the debugged equipment or cable are not in the same place, the other end should be guarded or locked by special personnel, and warning signs should be hung. After the instrument and grounding are checked correctly, the booster can only be boosted after the personnel are evacuated.

(2) Non-impact test of electrical equipment or materials, step-up or step-down should be carried out slowly. If the test is suspended or ended for any reason, the power supply should be cut off first to ensure safe discharge. And short-circuit that high-voltage side of the boosting device to the ground.

(3) When debugging the electric drive system and various high and low voltage switches, remove or lock the relevant switch handles, hang signs, and do not switch on.

(4) Measure the insulation resistance with a shaking table. No one is allowed to touch the tested line or equipment. After measuring the material of capacitive or inductive equipment, it must be discharged. In case of lightning, stop shaking the line insulation.

(5) Open circuit of current transformer is prohibited, and short circuit boosting of voltage transformer is prohibited. When electrical materials or equipment need to be discharged, they should wear insulating protective articles and discharge safely with insulating rods.

Six, the construction site power distribution and maintenance

(1) It is forbidden for a single person to cross obstacles to engage in repair work for on-site high-voltage power distribution equipment, regardless of whether it is live or not.

(2) When there is partial power failure in the high-voltage live area, the human body must keep a safe distance from the live part and be supervised.

(3) In the distribution room, the external high-voltage components and lines should be operated in sequence. When power failure is checked, the grounding wire should be hung, and the operating handle should be locked or hung with signs.

(4) Insulating gloves must be worn when checking electricity, and the electroscope should be used according to the voltage level. Check the electricity of each phase on both sides of the equipment or each phase of the line respectively. After verifying that the equipment or line has no electricity, short-circuit the equipment or line to be repaired to ground.

(5) The installation of grounding wire shall be carried out by two people. Connect the grounding terminal first, then the conductor terminal, and disassemble it in the reverse order. Wear insulating protective articles when disassembling and connecting. After the equipment or line is overhauled, the grounding wire can only be removed after a comprehensive inspection is correct.

(6) Multi-stranded soft bare copper wire with a cross section of not less than 25mm2 and special wire clamps shall be used for grounding wire. It is forbidden to use winding method for grounding and short circuit.

(7) Insulating gloves should be worn when closing the high-voltage switch with insulating rods or traditional mechanisms. When working outdoors in rainy days, in addition to wearing insulating protective articles, the insulating rod should have a rain cover and be supervised by a special person. It is forbidden to close the switch with load.

(8) The metal shell of electrical equipment must be grounded or connected to zero. The same equipment can be grounded and connected to zero. The same power supply system does not allow some equipment to adopt zero connection and the other part to adopt grounding protection.

(9) The rated current of fuse (chip) used in electrical equipment should be suitable for its load. It is forbidden to replace the fuse (chip) with other metal wires.

Seven, the construction site lighting installation

(1) The light source with high luminous efficiency and long service life should be used for the construction site lighting. Workplaces should not only be equipped with local lighting. High-pressure mercury lamp, high-pressure sodium lamp or iodine tungsten lamp should be used in large-area lighting places, and the clear distance between the lamp holder and combustible materials should be not less than 0.3m When installing metal support in mobile iodine tungsten lamp, the support should be stable, and the lamps and lanterns must be separated from the metal support with an insulating material of not less than 0.2m

(2) When lighting lamps are installed in the open air, waterproof lamps should be used, and the height from the ground should not be less than 3m. The lighting lamps in the shed and the site can be controlled in different ways, and the number of connecting lamps on each lighting branch line shall not exceed 10. If it exceeds 10, each lamp shall be equipped with a fuse.

(3) The indoor lighting lamps and lanterns should not be less than 2.4m from the ground. The number of lamps and sockets on each lighting branch line shall not exceed 25, the rated current shall not be greater than 15A, and it shall be protected by fuses or automatic switches.

(4) Generally, the lighting lamps on the construction site should be lamps with rated voltage of 220V, and screw lamp holders should be selected, instead of lamp holders with switches. The phase line is connected to one end connected to the center contact, and the zero line is connected to one end connected to the threaded port. The insulating shell of the lamp holder shall not be damaged or leaked, and the metal shell of the lighting lamp must be protected and connected to zero. A leakage protection switch must be installed in the single-loop lighting switch box.

(5) The lighting power supply voltage shall not be greater than 36V for local lighting, indoor plastering, terrazzo floor and other wet working environments. The power supply voltage of the lighting lamp working in particularly wet ground, boiler or metal container with good conductivity should not be greater than 12V. Work lights should be protected by plastic handles and net covers.

(6) The 6)36V lighting transformer must be of double winding type, and the secondary coil, iron core and metal shell must have reliable protection and zero connection. Fuses should be installed on the primary side and the secondary side respectively, and the length of the primary line should not exceed 3m. Lighting transformers must be protected from rain and smashing.

(7) Lighting circuit shall not be tied to metal scaffolding or gantry, and it is forbidden to pull on the ground. When lamps and lanterns need to be installed on metal scaffolding and gantry, the lines and lamps and lanterns must be insulated from them, and the height from the working face is greater than 3 m. The control circuit breaker should be equipped with fuses and rainproof measures.

(8) Lighting fixtures on the construction site shall be controlled by groups or single lamps.