On-site power safety knowledge Chapter 1 Generator
First, the generator room must be strictly rain-proof, leak-proof, to prevent sand blowing in. The ground should be kept dry, and wooden boards or insulating mats should be laid around the engine and switchboard.
2. Flammable and explosive articles shall not be stored in the generator room.
Third, the exhaust pipe of the generator must extend out of the house and stay away from flammable materials.
Four, the wire from the generator to the switchboard must be insulated wire, the joint should be strong and installed in the online slot.
Five, the power supply of the generator set should be interlocked with the external circuit power supply, and parallel operation is strictly prohibited.
Six, the rotating part of the generator must be equipped with protective cover and other protective equipment.
Article 2 Distribution room
First, the transformer room should be close to the power supply, well ventilated, rainproof and leakproof, and no sundries should be piled up.
Two, two switchboard ends should be repeated grounding wire, electrical connection.
Three, the front of the switchboard should have enough operation channels, and there should be enough maintenance channels behind the side.
Four, the transformer room door should be locked and hung? There is a danger of electric shock. No admittance for idle people? Warning signal.
Five, the transformer room should be equipped with sand box and insulation fire extinguisher.
Six, the switchboard should be installed short circuit, overload protection device and leakage protector. Each distribution line shall be numbered and marked with the use mark.
Seven, switchboard or distribution line maintenance should hang signs, stop, power transmission must be the responsibility of the specialist.
Article 3 Transmission lines
A, overhead lines must use insulated copper wire or insulated aluminum wire, must be set up in accordance with the electricity design.
Second, the overhead line must be located on the special pole, it is forbidden to set up on scaffolding, concrete pole can not have cracks.
Third, the implementation of overhead lines? Three-phase four-wire system? Power and lighting lines should be separated, and overhead lines should be distinguished. The distance between poles should not be more than 35 meters, and the height from the ground should not be less than 4 meters.
Four, cable trunk should be buried or overhead laying, it is forbidden to lay along the ground, and to avoid mechanical damage and medium corrosion, the joint should be located in the ground junction box.
Five, rubber cable overhead laying, should be set along the wall or pole, and fixed with insulating objects, it is forbidden to use bare metal wire to tie the line.
Six, indoor wiring must use insulated wires, using porcelain, porcelain (plastic) clip laying, the height from the ground shall not be less than 2.5 meters.
Seven, into the door line through the wall should wear pipe protection, and take rainproof measures, should not be less than 2.5 meters from the ground, outdoor end should be fixed with insulators.
Article 4 the distribution box and switch box
First, the distribution box and switch box should be installed in a dry and ventilated place, and should not be located in a place that is vulnerable to external solid impact and strong vibration. It must be rainproof and dustproof.
Second, the distribution box and switch box should be made of iron plate or high-quality insulating material. Distribution box and switch box should be installed correctly and firmly, and mobile distribution box and switch box should be installed on a solid bracket. The bottom should keep a certain vertical distance from the ground, generally 0.6~ 1.5 meters.
Three, distribution box, switch box connecting wire should be insulated wire, joint shall not be loose, can not have exposed live parts, mobile distribution box, switch box in and out of the line must use rubber insulated cable.
Four, distribution box, switch box electrical appliances must be in good condition, are not allowed to use damaged and unqualified electrical appliances. When installing, it shall be fastened on the electrical installation board according to the specified position, and shall not be skewed or loose.
Five, distribution box, switch box wire inlet and outlet should be located in the lower end of the box, it is strictly prohibited to be located in the top, side, back or door of the box, switch box center must be installed with leakage protector.
Six, all distribution boxes and switch boxes should be checked regularly by professional electricians. During inspection, the corresponding power switch at the next higher level must be turned off, and a power-off sign should be hung. Live working is strictly prohibited.
Seven, all distribution box, switch box in the process of use must be carried out in the following order:
(1) The power transmission operation sequence is: main distribution box? Distribution box? switch box
(2) The sequence of power outage operation is: switch box? Distribution box? General distribution box (except electrical emergency)
Article 5 electrical equipment:
First, each electrical equipment has its own dedicated switch box, which must be implemented? One machine, one brake and one insurance? System, it is strictly prohibited to have more than one brake.
Second, all the connecting piles of electrical equipment should be fastened and checked frequently, and all electrical equipment should be well grounded.
Three, all kinds of mechanical and electrical equipment, must be equipped with grounding and zero protection device, grounding resistance shall not be greater than 10? .
Four, electrical equipment should be stored in a dry place, all kinds of electrical equipment should have rain and moisture-proof facilities.
Five, electrical equipment must have a full-time electrician for maintenance, before maintenance must cut off the power supply and hang up? Leave the door open? Send, beware of wrong power transmission, in case of power failure during work, turn on the power switch immediately.
Article 6 Lighting equipment
1. General lighting, local lighting or mixed lighting shall be provided for night construction, material storage yard, construction sidewalk, office, canteen and dormitory.
Second, lamps with rated voltage of 220V are used in general places.
On-site electricity safety measures (1) Complete sets of power distribution equipment should meet the requirements of harsh on-site use conditions. Due to the harsh environment in the construction site, higher requirements are put forward for complete sets of distribution equipment. Therefore, IEC standards and some developed countries have specially formulated product standards for complete sets of equipment used in the construction site, and their special requirements are as follows:
(1) can adapt to a variety of unfavorable conditions on the construction site, such as impact, vibration, water splash, sun exposure, dust, etc. As far as impact is concerned, IEC 439-4 standard has specific provisions on the field impact strength and test method of complete sets of distribution equipment, which can be referred to IEC standard when selecting.
(2) The complete sets of power distribution equipment used in the construction site should be reused in various construction sites under different conditions and should have this adaptability.
(3) Complete sets of power distribution equipment used in the construction site should meet the needs of different personnel. Non-electrical personnel often use the power plug to connect to the power supply. The socket shall be installed in a socket box without exposed live wires, or on the outer wall of a distribution box with weatherproof sockets. Distribution boxes of switchgear and protective appliances with bare live conductors can only be operated by electrical personnel.
(4) There are many kinds of electrical equipment used in construction and installation on the construction site, which varies from place to place. Therefore, the capacity of switches and protective appliances should be relaxed, and the types and series should be reduced as much as possible to meet all kinds of electricity demand, facilitate replacement and reduce the number of spare parts.
(2) Line laying. As the lines on the construction site are outdoor temporary lines, which are vulnerable to various stresses and mechanical damage and accidents, the following measures should be taken:
① Use sheathed cable with protective performance.
(2) Avoid the stress on the line terminal connector.
(3) Avoid being hit or crushed when laying lines. When overhead lines cross roads, the height of overhead lines should meet the national standards, and underground cables should be protected by steel pipes, so as not to touch ordinary lines as much as possible.
(3) Daily inspection. The installation and use of electrical equipment in the construction site often change. In addition to the inspection before use, the inspection should be carried out every day during use to eliminate hidden dangers in time before accidents occur. Inspection items are:
① Whether the leakage protector is effective.
(2) Whether the melt rating and circuit breaker setting value are correct.
(3) Grounding leads, electrical equipment and PE wires are well connected and reliable.
(4) Whether the equipment and lines are in good condition, and whether the exposed live conductors are out of people's reach.
(4) Correct selection of grounding system. When the site is powered by a special transformer, TT or TN-S system should be adopted. When these two systems work normally, the PE line does not pass current and there is no voltage drop on it, so it will not generate voltage to ground on the equipment shell, which will cause danger. When TT system is adopted, leakage protector must be installed, while when TN-S system is adopted, grounding fault can often be cut off with fuses and circuit breakers, which is relatively simple. In addition, because the construction site is outside the protection range of equipotential bonding and the environmental conditions are harsh, the maximum disconnection time for portable and mobile equipment is 0.2s instead of 0.4s in TN system. For safety reasons, it is still necessary to install leakage protectors with working current not greater than 30mA on the sockets supplying power to these devices in TN system.
(5) Set the grounding electrode correctly. At the beginning of site construction, the site grounding electrode should be set at the main distribution box of power supply incoming line, and its resistance value depends on the protection requirements of grounding system. The foundation reinforcement of new buildings is often used as the grounding electrode of building electrical equipment, and some flat steel is buried in the foundation trench as the grounding electrode. These permanent grounding electrodes can also be welded with the above-mentioned field grounding electrodes in the construction stage to improve the grounding effect.
(6) Switch and protector shall be installed in the distribution box. Due to the harsh electrical conditions in the construction site, it is necessary to pay attention to whether the switches and protectors (except general ones) installed in the distribution box can meet the following requirements:
① Emergency switch. Because there are often cranes, winches, conveyor belts and other equipment on the construction site, these equipment often have some dangerous situations and stop urgently. Therefore, it is necessary to set an emergency switch to cut off the circuit in time and quickly.
② Electrical isolation. For some reason, the neutral line in low-voltage lines often has a certain potential, so it is often necessary to move equipment and repair electrical lines at the construction site. For ordinary three-pole appliances, the neutral wire cannot be disconnected. At this time, people are more likely to get an electric shock when they touch the zero line, so be sure to disconnect all phase lines and zero lines at the same time. In this way, the three-phase four-wire circuit should use four-pole electrical appliances, and the single-phase circuit should use two-pole electrical appliances.
③ Leakage protection. Because the insulation of electrical lines and equipment in the construction site is easy to be damaged, it may not only cause electric shock accidents in which human bodies directly contact live conductors, but also indirectly contact electric shock accidents due to the diffusion of voltage and fault voltage on the equipment shell. Therefore, the leakage protector must be installed correctly to prevent electric shock casualties.
In addition, whether it is TT system or TN system, the electrical lines and equipment on site should be protected by leakage protector, which can be set to level 2 or level 3. The socket circuit of portable and mobile equipment shall be equipped with I30MA leakage protector, other circuits and fixing devices.
1 and other construction organization design work have potential safety hazards in site electricity consumption, and technical electricity consumption safety measures are not in place.
The construction site is not only a special place for electrical safety technology, but also a place with special electrical hazards. To this end, the Ministry of Construction has specially formulated the Technical Specification for Temporary Electricity Safety in Construction Sites (J6J46? In 2005), it is stipulated that construction enterprises must strictly prepare the construction organization design of temporary electricity consumption before construction, and formulate technical measures for safe electricity consumption and electrical fire prevention measures. However, many construction enterprises do not follow the requirements of this specification, or always feel that the problem of construction electricity consumption is not very important. As long as the installation procedures are completed in the power supply department and the power cord is in place, you only need to take care of other things yourself? An electrician? Do it. Therefore, many construction enterprises have not carried out the construction organization design work such as technical measures, safety measures and management measures seriously, which is a common problem in construction enterprises at present.
2、? An electrician? The certified training is not standardized and inertia is illegal.
Perhaps it is because the construction enterprises are highly mobile and scattered, with scattered personnel and difficult management; Maybe it's because it's difficult to get the qualification for the training exam now. Direct operation on the construction site? An electrician? There are not many qualified workers, and they have neither obtained the electrician's network operation certificate nor the electrician's certificate of special industry issued by the relevant safety supervision department. Most electricians have not received strict training in basic electrician knowledge and power safety knowledge. Although construction enterprises are qualified to bid for construction projects, few electricians are certified after professional training. In this way, in actual operation, people are lucky, careless, self-righteous, eager for quick success and instant benefit, sometimes desperate and playing personal heroism, which will inevitably lead to safety accidents such as electric shock casualties and damage to electrical equipment. Due to the lack of electricity technology and safety management, the operators' awareness of self-prevention in electricity safety is relatively weak. In my opinion, accidents do happen by accident, but without professional basic knowledge and safety basic knowledge,