I. Management
If the capacity is above 50KW, the construction organization design of temporary electricity utilization shall be prepared, which includes:
1. Field exploration;
2. Determine the position and direction of power supply incoming lines, substations or power distribution rooms, power distribution devices and electrical equipment;
3. Calculate the load;
4. Select the transformer capacity;
5. Design the power distribution system:
1) Design distribution lines and select wires or cables;
2) Design power distribution device and choose electrical appliances;
3) design grounding device;
4) Draw the drawings of temporary power utilization project, mainly including the general plan of power utilization project, the layout of power distribution equipment, the wiring diagram of power distribution system and the design drawing of grounding device (plan and section).
6. Design lightning protection device;
7. Determine protective measures;
8. Formulate technical measures for safe electricity use and electrical fire prevention measures.
Second, the professional requirements
1. The installation, maintenance or dismantling of temporary electricity utilization projects must be completed by electricians, and the level should be suitable for the difficulty and technical complexity of the project.
2. All kinds of electricity users should do:
Master the basic knowledge of safe electricity use and the performance of the equipment used;
Before using the equipment, you must wear and equip the corresponding labor protection articles according to the regulations, and check whether the electrical devices and protective facilities are in good condition. It is forbidden to operate the equipment in spite of illness.
When you stop using the equipment, you must cut off the power supply and lock the switch box;
Responsible for protecting the load line, zero line and switch box of the equipment used, and report and solve the problems in time when found;
Handling or moving electrical equipment must be carried out after the electrician cuts off the power supply and properly handles it.
III. Safety technical documents
1. A safety technical file must be established for temporary electricity utilization on the construction site. Its contents are as follows:
All the information of temporary electricity construction organization design;
Modify the data of temporary power consumption group;
Technical disclosure materials;
Temporary electricity engineering inspection and acceptance form;
Test and inspection certificates and debugging records of electrical equipment;
Measure and record the grounding resistance, insulation resistance and leakage action parameters of the leakage protector;
Records of electrical installation, inspection, maintenance and removal;
Check the table regularly.
Safety technical files shall be established and managed by the electrical technicians in charge of the site. Among them, "Electrician's Installation, Inspection, Maintenance and Dismantling Work Records" can be entrusted to electricians, which will be reviewed and approved by the project manager every week, and will be filed uniformly after the temporary electricity utilization project is dismantled.
2. Temporary power consumption projects must be checked regularly, once a month on the construction site and once a quarter in the branch. When checking the branch, the grounding resistance and insulation resistance should be rechecked.
3. The inspection work should be carried out according to the partial project, and the unsafe factors must be handled in time, and the review and acceptance system should be implemented.
Four, the safe distance between the project under construction and the external power line.
The project under construction shall not be under high and low voltage lines, and no sheds, living facilities, components, shelves, materials and other sundries shall be erected.
See JGJ46-2005 for the minimum safe distance between buildings and overhead power lines.
The minimum safe distance between any part of the rotating boom or crane or the edge of the hoisted object and the roadside of the overhead line below 10KV shall be not less than 2m horizontally and 3m vertically.
The distance between the edge of non-heat pipe trench excavated on the construction site and the edge of buried cable trench shall not be less than 0.5m ..
If the minimum distance specified above cannot be reached, insulation and isolation protection measures must be taken and eye-catching warning signs should be hung.
When erecting protective facilities, it must be approved by the relevant departments, and the electrical engineering and technical personnel or full-time security officers are responsible for monitoring.
Five, zero
1. TN-S zero protection system must be adopted for power lines with neutral point directly grounded on the construction site.
2. The metal shell of electrical equipment must be connected with a special protective zero line, which is led from the zero line of working grounding distribution room or the zero line of the power supply side of the primary leakage protector.
3. Electrical equipment such as Yugoslav capital, civil air defense, tunnels, etc. on the construction site with damp or particularly harsh conditions must be well protected and connected to zero.
4. When the power supply system is used in the construction site and external power supply lines, the electrical equipment should be protected by zero connection or protective grounding according to local requirements, and some of them are not protected by zero connection and the other part is protected by grounding.
5. For lightning protection and grounding electrical equipment, repeated grounding must be done at the same time. The same grounding body can be used for repeated grounding and lightning protection grounding of the same equipment, and the grounding resistance should meet the requirements of repeated grounding resistance.
6. The electrical equipment and lightning protection device on the construction site can be grounded by natural grounding body, but the electrical connection should be ensured and the thermal stability of natural grounding body should be verified.
7. The protective zero line system on the construction site is strictly prohibited to be mixed with the working zero line.
8. Do not install a switch or fuse to protect the zero line.
9. The protective zero line shall be laid separately and shall not be used. Repeated grounding wire should be connected with protective zero line.
10. The cross section of the protection zero line shall not be less than that of the working zero line, and must meet the requirements of mechanical strength. The overhead laying distance of the protective zero line shall not be less than 12m, and the protective zero line shall be insulated copper wire or insulated aluminum wire not less than10m2.
1 1. The protective wire of hand-held electrical equipment shall be multi-stranded copper wire and rubber cable with good insulation, and its cross section shall not be less than 1.5 mM㎡. The protective zero line connected with electrical equipment shall be insulated multi-strand copper wire with a cross section of not less than 2.5M㎡.
12. The electrical equipment shall be protected by a special core wire connected to zero, and the core wire is prohibited from passing through the working current. The unified sign of protecting the zero line is the green/yellow double-color line. In any case, the green/yellow double-color line is not allowed to be used as a load line.
13. Under normal circumstances, the uncharged exposed conductive parts of the following electrical equipment should be protected and connected to zero:
Metal housings for motors, transformers, electrical appliances, lighting equipment and hand-held power tools.
Metal parts of transmission device of electrical equipment.
Metal frame of switchboard and control panel.
Metal frames of indoor and outdoor distribution devices and metal fences and doors near belts.
Metal protective pipes for power lines, steel cables for laying lines, crane tracks, metal operating platforms for sliding templates, etc.
Metal shell and bracket of electrical equipment such as switches and capacitors installed on power line poles.
Six, grounding and grounding resistance
1. The protective neutral line must be repeatedly grounded at the middle and end of the distribution line outside the distribution room or the main distribution box.
The grounding resistance value of repeated grounding devices at all parts of the protective zero line should not be greater than 10 ohm.
In the power system that allows the working grounding resistance to reach 10 ohm, the parallel equivalent resistance of repeated grounding is not greater than 10 ohm.
2. The grounding wire of each grounding device should be electrically connected with the grounding device at different points using more than two wires.
3. Aluminum wires shall not be used for connecting wires or underground grounding wires, angle steel or round steel shall not be used for vertical direct charged bodies, and rebar shall not be used.
4. The plugs of Class I handheld electrical equipment should be equipped with special protective neutral (grounding) contacts, and all plugs should be able to avoid using conductive contacts as grounding contacts by mistake.
5. In addition to protection and zero connection, all electrical equipment on the construction site must be equipped with leakage protection devices at the head end of the equipment load line.
Seven, lightning protection
1. In soil, the resistivity is less than 200 ohms. There is no need to set lightning protection grounding device for the poles in the table, and the iron feet of insulators should be connected with the grounding device in the distribution room at the incoming or outgoing lines.
2. Crane, tic-tac-toe frame, gantry and other mechanical equipment on the construction site shall be equipped with lightning protection devices if they are within the protection range of lightning protection devices of adjacent buildings and structures.
If the lightning rod on the highest mechanical equipment can protect other equipment according to the 60-degree protection range and eventually quit, other equipment may not be equipped with lightning protection devices.
3. The impact grounding resistance of all lightning protection devices on the construction site shall not be greater than 30 ohms.
4. The lightning protection downlead of each mechanical equipment can use the metal structure of the equipment, but the electrical connection should be ensured.
5. The length of lightning rod on mechanical equipment is 1-2m.
6. The power, control, lighting, signal and communication lines of the mechanical equipment with lightning rod shall be laid with steel pipes, which shall be electrically connected with the metal structure of the mechanical equipment.
Eight, distribution routes
wiring
1. The main wires should be laid underground or overhead, and it is forbidden to be laid along the ground, and mechanical damage and medium corrosion should be avoided.
2. The cable type should be selected according to the laying mode and environmental conditions, but a five-core cable must be used, and the conductor section should be determined according to the allowable current carrying capacity and allowable voltage loss.
3. The outdoor direct burial depth of the wire is not less than 0.7m, the upper and lower sides of the wire are evenly covered with fine sand with a thickness of not less than 5CM, and then covered with hard protective layers such as bricks.
4. When the cable passes through buildings, structures, roads and places vulnerable to mechanical damage, and is led from the ground to 0.2m underground, a protective sleeve shall be added, and the inner diameter of the protective sleeve shall not be less than 1.5 times of the outer diameter of the cable.
5. The parallel spacing between cable lines and nearby heating pipelines shall be no less than 2m, and the cross spacing shall be no less than1m..
6. The joint of directly buried cable shall be located in the ground junction box. The junction box should be waterproof, dustproof and resistant to mechanical damage, and far away from flammable, explosive and corrosive places.
7. When rubber cables are laid overhead, they should be laid along walls or poles and fixed with insulators. Bare metal wires are strictly prohibited as binding wires. The spacing between fixed points should ensure the load brought by the glue line with its own weight, and the maximum sag distance of the glue line should not be less than 2.5 meters.
8. Cable joints shall be firm and reliable, and shall be insulated and bandaged to maintain insulation strength, and shall not bear tensile force.
9. Temporary cable wiring in high-rise buildings under construction must be introduced by underground cables, and it is strictly prohibited to introduce through scaffolding. The vertical laying position of cables should make full use of the vertical holes in the shaft of the project under construction and be close to the load center. Each floor should have at least one fixed point. The horizontal laying of cables shall be rigidly fixed along the wall or door, and the maximum sag distance shall not be less than 2.0m..
indoor wiring
1. Indoor wiring must use insulated wires, porcelain bottles, porcelain clips, etc. , and the height from the ground shall not be less than 2.5 meters.
2. When the incoming line goes through the wall, it should be protected by wearing a pipe, and the distance from the ground is not less than 2.5 meters, and rainproof measures should be taken.
3. The outdoor end of incoming line shall be fixed with insulators.
4. The cross-section of wires used for indoor wiring should be determined according to the calculated load of electrical equipment, but the cross-section of aluminum wires should not be less than 2.5M㎡, and that of copper wires should not be less than1.5m2. 。
5. Non-cable wiring should be laid in damp places or underground, and the nozzle should be sealed. When laying with metal pipe, zero protection must be done well.
Nine, distribution box and switch box
Setting of distribution box and switch box
1. Power distribution box and lighting distribution box should be set separately. If placed in the same distribution box, the power and lighting circuits should be set separately.
2. The switch box shall be distributed by the final distribution box.
3. The main distribution box should be located near the power supply, and the distribution box should be located in the area where the load of electrical equipment is relatively concentrated. The distance between the distribution box and the switch box should not exceed 30m, and the horizontal distance between the switch box and the fixed electrical equipment it controls should not exceed 3m.
4. The distribution box and switch box shall be located in a dry, ventilated and normal temperature place, and shall not be installed in harmful media with serious damage such as gas, flue gas, steam, liquid, etc., and shall not be installed in places that are vulnerable to impact by foreign solid objects, strong vibration, liquid splashing and heat source baking, otherwise special protection treatment shall be made.
5. Around the distribution box and switch box, there should be enough space and passage for two people to work at the same time, and articles that hinder operation and maintenance should not be piled up, and there should be no shrubs or weeds.
6. The distribution box and switch box should be installed correctly and firmly, and the mobile distribution box and switch box should be installed on a solid bracket.
7. The vertical distance between the center of fixed distribution box and switch box and the ground should be greater than 1.4 and less than 1.6 meters, and the vertical distance between the center of mobile distribution box and switch box and the ground should be greater than 0.8 and less than 1.6 meters.
8. The electrical appliances in the distribution box should be installed on the metal or nonmetal wooden insulated electrical appliance installation board first, and then fixed in the distribution box as a whole. The metal plate shall be electrically connected with the iron distribution box.
9. The switchgear in the distribution box and switch box shall be fastened on the electrical installation board according to the specified position, and shall not be skewed or loose.
10. The working zero line in the distribution box and switch box shall be connected through the terminal board and separated from the protective zero line terminal.
1 1. The connecting wires in the distribution box and switch box shall be insulated wires, and the connectors shall not be loose, and there shall be no exposed live parts.
12. The metal box of the distribution box and switch box, the metal electrical installation plate and the uncharged metal base and shell of the electrical appliances in the box must be protected and connected through the terminal board.
13. The distribution box and switch box must be waterproof and dustproof.
electronic equipment
1. The electrical appliances in the distribution box and switch box must be reliable and in good condition. Damaged and unqualified electrical appliances are not allowed to be used and must meet the requirements of "three-level distribution and two-level protection".
2. The main distribution box should be equipped with main disconnector and shunt disconnector, main fuse and shunt fuse and leakage protector. The basic leakage protector has both overload and short-circuit protection functions, and there is no need to set shunt fuse or shunt automatic switch. The rating and action setting value of main switchgear should be compatible with that of parallel switchgear.
3. The main distribution box should be equipped with voltmeter, ammeter, watt-hour meter and other instruments.
4. The distribution box should be equipped with main disconnector and shunt disconnector, main fuse and shunt disconnector, main fuse and shunt fuse, and the rating and setting value of main switch should be compatible with that of shunt switch.
5. Each equipment should have a special switch box, and the system of "one machine, one brake, one leakage and one box" must be implemented. It is forbidden to use the same switch to directly control more than two electrical devices.
6. Switch box switchgear must be able to use electrical equipment under any circumstances and implement current isolation.
7. Leakage protector must be installed in the switch box, and the installation of leakage protector should meet the requirements. Electrical equipment under 36V and 36V can be exempted from installing leakage protector if the working environment is dry.
8. The leakage protector shall be installed on the load side of the power isolating switch of the distribution box and the load side of the power isolating switch of the switch box.
9. The selection of leakage protector shall meet the requirements of international leakage current action protector/residual current action protector GB6829- 1986. The rated leakage action current and rated leakage action time of the leakage protector in the switch box should be no more than 30MA and less than 0.1s.. The leakage protector used in damp and corrosive medium places should adopt splash-proof finished products, and its rated leakage current should not be greater than 65438.
10. The rated leakage action current and rated leakage action time of the two-stage leakage protectors in the main distribution box and switch box should be reasonably matched to make them have the function of step-by-step protection.
1 1. The power supply circuit with a capacity greater than 5.5KW should be controlled by automatic switching device or step-down starting device, and the brake should meet the requirements without damage.
12. The ratings of various switching appliances should be adapted to the ratings of the electrical equipment they control.
13. The inlet and outlet of distribution box and switch box should be located at the bottom of the box, and it is forbidden to be located at the top, side, back or door of the box.
Incoming and outgoing lines shall be bound with sheath and waterproof elbow. The wire harness shall not be in direct contact with the incoming and outgoing wires in the box, and the outgoing wires shall be arranged neatly. Incoming and outgoing lines of mobile distribution box and switch box must use rubber insulated cables.
14. It is forbidden to connect the power cord to the switch box with bolts.
15. Multi-channel power distribution in distribution box and switch box should be clearly marked.
16. Use and maintenance of distribution box and switch box:
All distribution boxes and switch boxes shall be marked with names and purposes, and marked with shunting signs;
All distribution boxes should be locked, and special persons should be responsible for the distribution boxes and switch boxes;
All distribution boxes and switch boxes shall be inspected and maintained once a month, and the inspection and maintenance personnel must be professional electricians. During inspection and maintenance, insulating shoes and gloves must be worn as required, and electrical insulating tools must be used;
When the distribution box and switch box are inspected and maintained, the corresponding power switch at the next higher level must be turned off, and power-off signs should be hung. It is forbidden to use electric belt to work.
17. All distribution boxes and switch boxes must be operated in the following order:
The sequence of power transmission operation is: main distribution box-distribution box-switch box.
The sequence of power outage operation is: switch box-distribution box-main distribution box.
18. When the shutdown time on the construction site exceeds 1H, the power switch box should be closed and locked.
19. Switch box operators must be familiar with the correct operation methods and corresponding technical requirements of switch electrical appliances. No sundries shall be placed in the distribution box and switch box, and they shall be kept clean and tidy.
20. The distribution box and switch box shall not be connected with other temporary electrical equipment.
2 1. When replacing the fuse melt, it is forbidden to use the melt that does not meet the original specifications for replacement.
22. The inlet and outlet lines of distribution box and switch box shall not bear external force, and it is forbidden to contact sharp metal fracture and strong corrosive medium.
Outdoor lighting
general clause
1. General lighting, local lighting or mixed lighting shall be provided in places with potholes, night construction or poor natural lighting, as well as workshops, yards, roads, warehouses, offices, canteens and dormitories. Only local lighting is installed in three workplaces.
After the power failure, the operators need to evacuate the special project on site in time, and emergency lighting with its own power supply must be installed.
2. Lighting sources with high luminous efficiency and long service life should be used for on-site lighting, and high-pressure mercury lamps, high-pressure sodium lamps or mixed tungsten halogen lamps should be used for places requiring large-area lighting.
3. The choice of illuminator shall be determined according to the following environmental conditions:
When the humidity is normal, choose an open illuminator;
In wet or especially wet places, choose closed waterproof illuminator or open or illuminator with waterproof lamp holder;
Places containing a lot of dust but without explosion and fire danger. Adopt dust-proof illuminator;
For places with explosion and fire danger, corresponding lamps must be selected according to the level of dangerous places;
In places with large vibration, choose anti-vibration illuminator;
For places with strong corrosion such as acid and alkali, use acid and alkali-resistant illuminators.
4. The quality of lighting appliances and equipment shall comply with the provisions of relevant standards and specifications, and aging or damaged insulating appliances and equipment shall not be used.
mains lighting supply
Lamps with rated voltage of 220V should be selected in general places.
1. safe voltage luminaries should be used in the following special places.
The lighting power supply voltage of tunnels, civil air defense projects, places with high temperature, conductive dust or lamps, and places below 2.5 meters from the ground shall not be greater than 36V.
The voltage of lighting power supply in damp and charged places should not be greater than 24 V.
The voltage of lighting power supply working in particularly humid places, ground with good conductivity, boilers or metal containers should not be greater than 12V.
2. The number of lamps and sockets in each single-phase circuit in the lighting system shall not exceed 25, and fuse protection with fuse current below 15A and 15A shall be installed.
3. The use of portable lamps shall meet the following requirements:
The power supply voltage shall not exceed 36V.
The lamp body and handle should be firm, well insulated, heat-resistant and moisture-proof.
The lamp holder is firmly combined with the lamp body, and the lamp holder has no switch.
There is a metal protective net outside the light bulb.
The metal mesh, reflector and hook are fixed on the insulating part of the lamp.
4. The lighting transformer must be of double winding type, and autotransformer is strictly prohibited.
5. The primary power cord of portable transformer should be rubber cable or plastic cord, and the protective zero line should be green/yellow double wire, with no connector in the middle, and the length should not exceed 3m. Power sockets should be sockets with grounding contacts.
6. The working zero line section shall be selected according to the following provisions:
In single-phase and two-phase lines, the cross section of neutral line is the same as that of phase line.
In a three-phase four-phase circuit, when the illuminator is an incandescent lamp, the cross section of the zero line is selected according to 50% of the current carrying capacity of the phase line, and when the illuminator is a gas discharge lamp, the cross section of the zero line is selected according to the maximum load current.
In a three-phase lighting circuit that is cut off phase by phase, the cross section of the zero line is equal to the cross section of the phase line. If the zero line is used in several lines, the cross section of the zero line is selected according to the current of the maximum load phase.
lighting equipment
1. The metal shell of lighting lamps must be connected to zero with protection, and the lighting switch box of single-phase circuit must be equipped with leakage protector.
2. Outdoor lamps and lanterns shall not be less than 3 meters from the ground, and indoor lamps and lanterns shall not be less than 2.5 meters.
3. Each lamp of the street lamp should be protected by a separate fuse, and the lamp holder should be waterproof.
4. Fluorescent tubes shall be fixed by pipe sockets or hanging chains, and hanging ballasts shall not be installed on flammable structures.
5. The installation height of sodium, thallium, indium and other metal halide lamps should be more than 3 meters, and the lamp wire should be fixed on the terminal and not close to the surface of the lamp.
6. The base of floodlight should be installed firmly, and the pivot should be tightened in the required optical axis direction.
7. Screw lamp holder and wiring shall meet the following requirements:
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.
8. The internal wiring of lamps and lanterns must be firm, and the external wiring of lamps and lanterns should be reliably insulated and bandaged.
9. Wiring switch shall be used for lighting of temporary works, and the installation position of the switch shall meet the following requirements:
The height of the cable switch is 2-3m from the ground, the horizontal distance between the entrance and exit is 0. 15-0.2m, and the cable exit should be downward.
The height of other switches from the ground is 1.3m, and the horizontal distance from the entrance and exit is 0.15-0.2m. It is forbidden to install the socket and handle switch aside and the switch on the bed.
10. The phase lines of electrical appliances and lamps and lanterns must be controlled by switches, and the phase lines shall not be directly introduced into lamps and lanterns.
1 1. For projects or mechanical equipment under construction that affect the passage of aircraft or vehicles at night, eye-catching and coordinated red signal lights must be installed, and the power supply should be located at the front side of the main switch on the construction site.
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