The hottest test site for laws and regulations of

2019 junior Certified Safety Engineer "laws and regulations" examination site: safe electricity use and electrical fire prevention measures in construction engineering

[Abstract] universal school has sorted out the 2019 junior Certified Safety Engineer "laws and regulations" examination site: safe electricity use and electrical fire prevention measures in Construction Engineering, which is summarized as follows for your reference! For more review information, 1 is circular arc synchronous gear belt material. Please pay attention to the junior registered safety engineer channel of universal school. I wish you a happy study

safe electricity use and electrical fire prevention measures for construction projects:

1. Safe electricity use measures

(1) grounding and neutral connection

TN-S neutral connection protection system (i.e. three-phase five wire system) must be adopted in the low-voltage power lines directly grounded at the neutral point dedicated to the construction site

a. the protective zero line shall be led out by the working grounding wire or the zero line in the distribution room or the zero line on the power side of the first level leakage protector

b. The protective zero line shall be laid separately from the working zero line and shall not be used for other purposes. The protective zero line PE must adopt green/yellow double color line

c. The protective zero line must be repeatedly grounded at least three places in the middle and end of the distribution line in the distribution room (or general distribution box), and the repeated grounding wire should be connected with the protective zero line

d. the cross section of the protective zero line shall not be less than that of the working zero line, and must meet the requirements of mechanical strength. When the overhead laying spacing is not more than 12 meters, the cross section of the insulated copper wire shall not be less than 10mm2, and the cross section of the insulated aluminum wire shall not be less than 16mm2; The protective zero line connected to the electrical equipment is insulated stranded copper wire with a section of not less than 2.5mm2

e. under normal conditions, metal shells, frames, components, pipelines, tracks, metal operation platforms of electrical equipment that are not electrified, as well as metal fences and metal doors close to electrified parts, shall be connected to neutral with protection

f. the direct working grounding resistance of the neutral point of the power supply transformer shall not be less than 4 ohms, and the repeated grounding resistance of the protective zero line shall not be less than 10 ohms. It is not allowed to make protective neutral connection for some equipment and protective grounding for others

(2) configure leakage protectors

a. the distribution box (distribution room) and switch box at the construction site shall be equipped with at least two-level leakage protectors

b. The leakage protector should be current operated. In general, the rated leakage action current of the leakage protector should not be greater than 30mA, and the rated leakage action time should not be greater than 0.1s; The limit value of the product of the rated leakage action current and the rated leakage action time of the leakage protector in wet and corrosive places is (greater than) 30ma s;

c. The selection of leakage protector in the switch box should be compatible with the actual situation such as the capacity and number of phases of the power equipment. For example, three-phase three wire leakage protector with matching parameters should be selected for three-phase motor; The power for lighting must be separated from that for power, and the single-phase two-wire leakage protector should be selected for lighting

(3) the switch box is set according to three levels, that is, the switch box of the main distribution box and the distribution box. The switch box cannot be more than three meters away from the machine. The switch box implements one machine, one switch and one leakage protection

(4) external power protection

a. the minimum safe operating distance between the outer edge of the project under construction (including scaffolding) and the sideline of the external power overhead line: 4 meters below 1kV; The voltage of 1kv-10k is 6 meters

b. The minimum vertical distance when the motorway on the construction site crosses the external power overhead line: 6 meters for voltages below 1kV and 7 meters for voltages between 1kv-10kv

(5) distribution system

a. all wires must be erected using poles, insulators, cross arms, etc. according to the specification requirements

b. The switchgear and electrical devices must be intact

c. switching appliances and electrical devices must be installed correctly and firmly, and shall not be placed on the ground

d. The joints between the wires with wires must be insulated and wrapped, and the live wires must be well insulated

e. It is strictly forbidden to erect, hang or press the live wire on the scaffold or other objects

f. the distribution box and switch box shall be marked with name, purpose and shunt; The distribution box and switch box shall be equipped with locks and be in the charge of a specially assigned person

g. The interior of the electric box and its surrounding area have brought confidence to the extruder enterprise. The area should be free of debris, shrubs and weeds

h. It is strictly forbidden to use fancy wires for outdoor electricity, copper wires or other metal wires instead of fuses, and it is strictly forbidden to pull wires, sockets, electric stoves and rice cookers in the workers' dormitory

i. electrical devices should be repaired regularly. During the maintenance, it must be done:

①. Power failure

② hang the power-off sign and connect the necessary grounding

③. Maintenance by professional electrician of corresponding level

④ maintenance personnel should wear insulating shoes and gloves and use electrical insulating tools

⑤ organized and specially assigned personnel shall be responsible for unified command

(6), lighting

a, general lighting, local lighting or mixed lighting of equipment such as places where construction is carried out at night or natural lighting, material and tool stacking yards, roads, warehouses, offices, canteens, dormitories, etc

b. Choose the corresponding illuminator according to the environmental conditions of the place of use

c, the voltage of the portable lamp shall not exceed 36V, and the lighting voltage in places where the height of the lamp from the ground is less than 2.4 meters shall not be greater than 36V. The lighting voltage in wet and accessible places with electrified bodies shall not be greater than 24V

d. set up guards, red signal lighting and accident lighting as required, and its power supply should be set in the front of the main power switch on the construction site, and equipped with power supply

(7) carry out training on basic knowledge of safe electricity use for all kinds of electricity users

2. Organizational measures for safe use of electricity

(1) establish the preparation and approval system of temporary power construction organization design and technical measures for safe use of electricity, and establish corresponding technical files

(2) establish a technical disclosure system

introduce the general intention, technical content and precautions of the construction organization design of temporary power utilization and technical measures for safe power utilization to professional electricians and all kinds of power users, and perform the signing procedures of the discloser and the Discloser on the written data of technical disclosure, indicating the date of disclosure

(3) establish a safety inspection system. From the completion of the temporary power use project, the temporary power use project shall be tested regularly, mainly including the grounding resistance value, the insulation resistance value of electrical equipment, the action parameters of leakage protector, etc., to monitor whether the temporary power use project is safe and reliable, and make testing records

(4) establish electrical maintenance system. Strengthen daily and regular maintenance work, find and eliminate hidden dangers in time, and establish maintenance work records, recording maintenance time, location, content, technical measures, treatment results, maintenance personnel, acceptance personnel, etc

(5) after the completion of the construction project, the demolition of temporary power projects should be organized and directed in a unified way, and it must be stipulated that the V-0 flame retardant characteristics (thickness of 0.4 mm (3.0 mm)) room, personnel, procedures, methods, precautions and protective measures should be maintained during the demolition

(6) establish a safety inspection and evaluation system. Construction management departments and enterprises should regularly inspect and evaluate the safety of on-site electricity use in accordance with the "scoring standard for building safety inspection" in which the clamping force of jgj5 decreases

(7) establish a safe electricity system, and implement the operation, supervision and maintenance of each part of the temporary electricity project in sections, blocks and units to each person, supplemented by necessary rewards and punishments

(8) establish safety education and training system. Professional electricians and all kinds of electricity users shall be regularly educated and trained on electricity safety, and those who pass the examination shall work with certificates. It is forbidden to leave the post without certificate or at will

(9) strengthen the leadership system of safe electricity use and improve the quality of electricity technology team

3. Technical measures for electrical fire prevention

(1) reasonably configure, set and replace various protective appliances to reliably protect the overload and short-circuit faults of appliances and equipment

(2) do not stack flammable, explosive and strong corrosive media around electrical devices and lines, and do not use fire sources

(3) in places where electrical devices are relatively concentrated, such as substations, distribution rooms, generator rooms, etc., insulating fire extinguishers are equipped, and fireworks are prohibited

(4) strengthen the insulation between phases and phase to ground of electrical equipment to prevent flicker

(5) reasonably set lightning protection devices

4. Electrical fire prevention organization measures

(1) establish a management system for inflammables, explosives and strong corrosive media

(2) establish an electrical fire prevention system, strengthen the control of fireworks in key places of electrical fire prevention, and set up no fireworks signs

(3) establish an electrical fire prevention education system, often carry out electrical fire prevention knowledge education and publicity, and improve the electrical fire prevention consciousness of all kinds of power users

(4) establish an electrical fire prevention inspection system and deal with problems in a timely manner

(5) strengthen the leadership system of electrical fire prevention and establish an electrical fire prevention team

the content of this article is the examination site of laws and regulations for junior certified safety engineers in 2019: safe electricity use and electrical fire prevention measures in construction projects, for your reference and study! To view more review materials for junior registered safety engineers, click "click free download>;>;>; safety engineer test questions/test site essence" at the bottom of the article, and more free contents are included