October 30, 2023
Electricians aren't paid well and aren't valued by people, but risk factor is very high. If you don't pay attention, a broken appliance is a minor matter and can damage your body or even threaten your life. To be an electrician, you must be careful and you must not forget every step of work process, and order must not be wrong. Today we will look at some key points of safe electrician work, and please keep every electrician friend in mind!
1. General provisions
1. Electricians are classified as special operations personnel. After passing unified examination at local safety supervision bureau, they must issue a national unified "special operations personnel work certificate" before they are allowed to work on job, and they will be regularly reviewed every three years, years and can be applied for first time in six years.
2. Two people need to do electrical work at same time, one person works and other one controls.
3. When working on electrical lines (equipment), completely or partially de-energized, equipment (line) must be disconnected from power source, and measures must also be taken to prevent sudden discharges of electricity to parts and equipment. (lines) that can be powered. If necessary, protection against short circuits must be provided.
4. When overhauling electrical equipment (lines), it is necessary first of all to turn off power supply, (remove knife switch, remove insurance), lock junction box, hang a warning sign “No one should”. works, does not turn on. Or send someone to take care of you.
5.All insulation testing instruments must be stored properly and no other use is strictly prohibited.They must be stored in a dry and clean tool cabinet and must be regularly checked and calibrated according to rules of use.
6. When working near working equipment, it is strictly forbidden to use steel (roll) rulers to measure corresponding dimensions.
7. When using a hammer to connect electrode, hand holding hammer cannot wear gloves. The person holding ground electrode should be at side. Use tools to clamp and stabilize ground electrode. goggles when drilling concrete holes or drilling holes on back.
8. When using induction method to dry an electrical box or transformer, case must be grounded.
9. When using hand-held power tools, case must be well grounded. It is strictly forbidden to screw case ground wire and working neutral wire together into socket. It is necessary to use second wire with ground and third socket with ground.
10. When laying wires, you must choose a suitable wire stripping sponge, and core of wire must not be damaged. When cutting end of wire, edge of knife must be directed outward, and force must be uniform.
11.The rated current of fuse used in electrical equipment must be compatible with its load capacity. It is forbidden to replace fuse with a large one or replace fuse with its metal wire.
12. Before work it is necessary to carry out full preparation. Person responsible forwork, must organize safety measures and precautions for all personnel in accordance with requirements and clearly divide the work. Inexperienced workers and emotional staff cannot be assigned to important technical work and climbing operations.
13. Operators are prohibited from drinking alcohol before work, during work they must be neatly dressed, concentrated, and will not be allowed to leave their posts without permission.
Second, installation
1. The power supply at construction site should use a three-phase five-wire (HN-S) system. The metal shell and wire pipe of all electrical equipment should be securely connected to a special protective neutral line. have at least two connection points, and protective zero line must not be equipped with switches or fuses.
2. The protective neutral line must be laid separately and should not be used for other purposes. In addition to grounding in switchboard or junction box, it must be re-grounded at middle and end of line, and must be connected to protective neutral line, and its grounding resistance does not exceed 10 ohms.
3.The cross section of protective neutral wire must be no smaller than cross section of working neutral wire.At same time, it must meet requirements of mechanical strength.When distance between air laying of protective neutral wire is more than 12m, protective neutral wire should choose insulation less than 10m㎡ Copper wire or insulated aluminum wire less than 16m㎡.
4. The cross section of protective neutral wire connected to electrical equipment must be at least 2.5 m² of insulated stranded copper wire. The uniform marking of protective neutral wire is a green-yellow double color line. .
5. The cross section of neutral line of a single-phase line is same as that of phase line, and cross section of working zero line and zero protection line of three-phase line is at least 50% of cross section of phase line.
6. The span of overhead line should be no more than 35 m, and distance between lines should be at least 0.3 m. The phase sequence of overhead line is arranged: facing load on left, these are L1, N, L2, L3, PE (Note: L1 , L2 and L3 - phase wires, N - working neutral wire, PE - neutral wire of protection).
7. Within span of overhead line, number of joints of each tier of overhead line should not exceed 50% of number of cores of tier, and only one joint is allowed for wire. railways, highways, rivers. There should be no joints within spans of power lines.
8. For overhead lines, concrete or wooden poles should be used. Concrete poles should not have bare veins, circumferential cracks and bends. Wooden poles should not be rotten. Tip diameter should be at least 130mm.1/10 plus 0.6 m , but in soft ground, increase embedment depth accordingly or use reinforcement such as cartridges.
9. When laying a rubber cable overhead, it should be located high along a wall or pole and fixed with insulators. The use of uninsulated metal wires as a strapping is strictly prohibited. The maximum distance of arc sag of cable should be at least 2.5 m.
10. The junction box and junction box should be installed in a dry, ventilatedplace with normal temperature. The box must be protected from rain, dust and locked. Specify purpose, height from ground to bottom of fixed box should be more than 1.3m and less than 1.5m, and height of bottom of mobile box should be more than 0.6m and less than 1.5m. Electrical appliances and wiring in box should be carefully installed, checked and repaired. once a month. The metal back seat and body must be connected to zero for protection, and all sorts of things cannot be put into box.
11. The rated operating leakage current and rated running time of two-stage leakage protection in main junction box and junction box must be reasonably matched so that they perform hierarchical protection function. Each electrical equipment must have its own "one car, one gate" system must be implemented in a special junction box, and leakage protection devices must be installed.
12. The input and output of wires in junction box and junction box must be at bottom of box. It is strictly forbidden to install on top, side, rear or outside of door of box. waterproof bend, wiring harness should not be in direct contact with box inlet and outlet, and rubber insulated cables should be used for inlet and outlet of mobile junction box and junction box.
13. In junction box of each electrical construction machine or hand-held power tool, a disconnect switch and overload, short-circuit and leakage protection devices should be installed, and load line should be stranded copper without connections. according to its capacity. Rubber-sheathed flexible cable or plastic-sheathed flexible wire, conductor connections must be strong and reliable, and insulation must be good.
14.The lighting transformer must be of two-winding type. Self-connecting transformers are strictly prohibited. The light switch must control live wire. When using running lights, supply voltage must not exceed 36 volts.
15. When installing power cord of equipment, one end of electrical equipment must be installed first, and then power end must be installed, and when it is removed, reverse must be done.
Third, maintenance of electrical equipment
1. Tools and maintenance tools should be checked frequently to keep insulation in good condition, and unqualified tools and maintenance tools should not be used.
2.After dismantling and overhaul of engine and electrical appliances, ends of wires should be wrapped with insulating cloth in time.After dismantling high-voltage motor and high-voltage electrical appliances, ends of wires must be short-circuited. closed and grounded.
3. When working on high and low voltage electrical lines, power must be turned off, and work under voltage is generally not allowed.
4.After a power failure, equipment and lines must be equipped with a qualified electroscope in front of ground wire.The operation can only be performed after electrical check confirms absence of electricity in accordance with regulations.The portable wire must be soft bare copper wire with a section of 25 m², there should be no broken cores and kinks.
5. Connecting and disconnecting ground wire should be done by two people, one person watching and one working, and insulated gloves should be worn.
6. Before using leg buckle and pedal harness, make sure they are strong and secure. The leg buckle should be selected according to size of electric pole. The pitch must be appropriate when pedal is on pole. ., Fasten it firmly, and place knot on left and right sides of front side.
7. Before climbing poles, it is necessary to check if roots of wooden poles are not rotten, not hollow (pine poles no more than 1/4, and spruce poles no more than 1/3), original traction cables, side piles in good condition and cement posts in good condition. It should be checked that appearance is flat, smooth, no exposed steel bars, no obvious cracks, and no obvious tilting and sagging of body of bar.
8. All staff on pole and on ground must wear safety helmets and keep a good eye on work area to prevent pedestrians and vehicles from passing. Materials to be moved should be moved using ropes or tool bags. , and tossing up and down is prohibited.
9. During a thunderstorm and strong wind above 6 supports, work on supports is not allowed.
10. Serial connection of protective neutral line of several electrical equipment is not allowed.
11. There should be two people on duty in substation (distribution) room. For low power substation (distribution) room, when one person is on duty, regardless of whether high-voltage equipment is live or not, inspection and repair work are not allowed.
12. When working in conditions of a partial power outage on a high-voltage electrified areake distance between operator and electrified equipment must comply with safety regulations, and when transporting tool, it is necessary to maintain a certain safety distance from electrified equipment. and materials.
