Common sense of safe electricity

1. Why must the lighting switch be connected to the live wire?

If the lighting switch is installed on the zero line, although the lamp is not turned on when it is turned off, the phase line of the lamp head is still connected, and people think that the lamp is not turned on, and they will mistakenly think that it is in a power off state. In fact, the voltage to earth at each point on the lamp is still a dangerous voltage of 220 volts. If people touch these actually charged parts when the lights are off, it will cause an electric shock accident. Therefore, all kinds of lighting switches or switches of single-phase small-capacity electrical equipment can only ensure safety if they are connected in series on the fire line.

2. How to install single-phase three-hole socket correctly? why?

Generally, single-phase electrical equipment, especially mobile electrical equipment, should use three-pin plugs and three-hole sockets. There is a special protection zero (ground) jack on the three-hole socket. When zero-connection protection is used, some people often directly connect this hole terminal to the zero line introduced into the socket only in the bottom of the socket. This is Extremely dangerous. If the zero line of the power supply is disconnected, or the fire (phase) line and the neutral line of the power supply are reversed, the metal parts such as the casing will also carry the same voltage as the power supply, which will cause electric shock.

Therefore, the dedicated grounding jack should be connected to the dedicated protective grounding wire when wiring. When using zero-connection protection, the zero-connection line should be specially drawn from the power supply end, and the zero line of the inlet should not be used nearby.

3. Why is it strictly prohibited to bury plastic insulated wires directly in the wall?

(1) After long-term use of plastic insulated wires, the plastic will aging and crack, and the insulation level will be greatly reduced. When the circuit is overloaded or shorted for a short time, it is easier to accelerate the damage of the insulation.
(2) Once the wall gets wet, it will cause a large area of ​​electricity leakage and endanger personal safety.
(3) Directly buried plastic insulated wires are not conducive to line maintenance and repair.

4. Why use leakage protector?

Leakage protector, also known as leakage protection switch, is a new type of electrical safety device. Its main uses are:
(1) Prevent electric shock caused by leakage of electrical equipment and electrical lines.
(2) Prevent single-phase electric shock accidents in the process of using electricity.
(3) Cut off the single-phase ground fault in the operation of electrical equipment in time to prevent electrical fire accidents caused by electric leakage.
(4) With the improvement of people's living standards and the continuous increase of household appliances, in the process of using electricity, personal electric shocks and fire accidents caused by defects in electrical equipment itself, improper use, and unfavorable safety technical measures, give people's lives And the property has brought undue loss, and the appearance of the leakage protector has provided reliable and effective technical means for preventing various accidents, cutting off the power in time, protecting equipment and personal safety.

5. What is the main reason for the electric shock accident?

Statistics show that the main causes of electric shock accidents are as follows:
(1) Lack of electrical safety knowledge, fly a kite near the high-voltage line, climb up the high-voltage electric pole and dig the bird's nest; after the low-voltage overhead line is disconnected, go to the live wire by hand without stopping the power; the dark night live wire touch the live body; Knife gate with rubber cover.
(2) Violating the operating rules, connecting lines or electrical equipment live without taking the necessary safety measures; touching damaged equipment or wires; mistakenly accessing live equipment; live lighting fixtures; live repair power tools; live mobile electrical equipment; Wet hands twist the bulb and so on.
(3) The equipment is unqualified and the safety distance is not enough; the grounding resistance of the two-wire one-ground system is too large; the grounding wire is unqualified or the grounding wire is disconnected; the insulation damage conductor is exposed outside.
(4) The equipment is out of repair, the wind blows the line or the electric pole is not repaired in time; the bakelite damage of the rubber cover knife gate is not changed in time; the motor wire is damaged, which causes the shell to be live for a long time; The device casing is live.
(5) For other accidental reasons, walking at night touches the live wire that fell on the ground.

6. What rescue measures should be taken in case of electric shock?

In the event of an electric shock, while ensuring the safety of the rescuers themselves, you must first try to quickly disconnect the electric shockers from the power source, and then perform the following emergency repair work.

(1) Unfasten the tight clothing that prevents the electric shock person from breathing.
(2) Check the oral cavity of the shocked person, clean up the mucus in the oral cavity, and remove any dentures.
(3) Rescue immediately on site, such as respiration, use mouth-to-mouth resuscitation. If the heart stops beating or irregularly vibrates, artificial chest compression can be used. Never stop for no reason.

If there is a second person besides the rescuer on the scene, the following work should also be carried out immediately:
1) Provide tools and equipment for first aid.
2) Dismiss the on-site miscellaneous personnel.
3) Keep sufficient lighting and air circulation on site.
4) Report to the leader and ask the doctor to come to the rescue.

Experimental research and statistics show that if you start treatment 1 minute after electric shock, 90% can be saved; if you start rescue 6 minutes after electric shock, there is only 10% chance of survival; The possibility of saving lives is extremely small. Therefore, when someone is found to be electrocuted, they should compete against each other and use all possible methods.

7. What are the measures for safe electricity use at home?

With the popularization and application of household appliances, it is very important to correctly grasp the knowledge of safe electricity use and ensure the safety of electricity use.
(1) Do not buy fake and inferior household products with "three noes".
(2) There should be a complete and reliable power cord plug when using home appliances. Grounding protection shall be adopted for household appliances with metal shells.
(3) Do not install switches and fuses on the ground and neutral lines. It is forbidden to connect the ground wire to the water and gas pipelines.
(4) Do not touch live equipment with wet hands or wipe live equipment with a damp cloth.
(5) Do not pull the wires indiscriminately, and do not move the live equipment casually.
(6) When inspecting and repairing household appliances, the power supply must be disconnected first.
(7) When the power cord of household appliances is damaged, it should be replaced immediately or wrapped with insulating cloth.
(8) When there is a fire in household appliances or wires, the power supply should be disconnected before extinguishing the fire.

8. How to prevent burning of household appliances?

The rated voltage of commonly used household appliances is 220 volts, and the normal supply voltage is around 220 volts. When the power supply voltage rises temporarily due to natural disasters such as lightning strikes in the power supply line, the three-phase load unbalanced house line is out of repair, the zero line breaks, or the phase voltage rise due to human misconnection, etc. , It will increase the current and cause home appliances to burn due to overheating. To prevent the burning of household appliances, it is necessary to start from the following aspects: one is to disconnect the power as much as possible when the electrical equipment is not in use; the second is to modify the old and out of repair household wire; the third is to install an overvoltage protection leakage switch.

  9. How to choose the fuse for residential households?

The fuse for residential households should be selected according to the size of the electricity consumption. When using a 5A ammeter, the fuse should be greater than 6A and less than 10A; when using a 10A ammeter, the fuse should be greater than 12A and less than 20A, that is, the selected fuse should be 1.2 ~ 2 times. The selected fuse should be one that meets the regulations, and can not be used with multiple small-capacity fuses, not to mention the use of copper wires instead of fuses.

  10. What are the basic requirements for leakage protectors?

Technically, the following requirements should be met:
(1) The sensitivity of the electric shock protection should be correct and reasonable, and the general starting current should be in the range of 15 ~ 30 mA.
(2) In general, the operating time of the electric shock protection should not exceed 0.1 second.
(3) The protector should be equipped with the necessary monitoring equipment to prevent the loss of protection when the operating status changes. For example, the voltage-type electric shock protector should be equipped with a neutral grounding device.

11. How to prevent electrical fire accidents? What to do after a fire?

First of all, when installing electrical equipment, the quality must be ensured, and the requirements for safety and fire protection should be met. Qualified electrical equipment should be used. Damaged switches, lamp caps, and damaged wires cannot be used. The connectors of the wires should be firmly connected according to the prescribed connection method and wrapped with insulating tape. Tighten the screws on the wiring of the wiring pile head and the terminal to prevent poor contact due to loose wiring. After the electrician installs the equipment, it does not mean that it can be done once and for all. During the use of the user, if the wiring of the lamp head and socket is loose (especially the wiring of the mobile electrical plug is easy to loose), the contact is poor or there is overheating, find an electrician to deal with it .

Secondly, do not place oil, cotton, wood chips, wood and other consumables near low-voltage lines and switches, sockets, and fuses.
Before the electrical fire, there is a kind of warning, which should be paid special attention to, because the electric wire will first scorch the insulation sheath, and emit an unpleasant smell of burning rubber and plastic. Therefore, when you smell this smell, you should first think that it may be caused by electrical reasons. If you can't find other reasons, you should immediately switch off the power and stop the power until you find out the reason and handle it properly.

In the event of a fire, whether it is caused by electricity or not, first of all, we must find a way to quickly cut off the power supply within the scope of the fire. Because, if the fire is caused by electricity, the power supply is cut off, and the source of the fire is cut off; if the fire is not caused by electricity, the insulation of the wire will be burned out. If the power supply is not cut off, the burnt wire will cause Short-circuiting the wires causes a wider range of wires to catch fire. After an electrical fire, cover soil, sand, or fire extinguishers, but foam fire extinguishers must never be used, so the extinguishing agent is conductive.

12. Common sense of household safety electricity

(1) Each family must have some necessary electrical appliances, such as electroscope, screwdriver, rubber pliers, etc., and must also have various specifications of fuse tools and fuses suitable for the right to use household appliances.
(2) Each household electric meter must be equipped with a general insurance, and the electric meter should be equipped with a main knife gate and a leakage protection switch.
(3) In any case, it is strictly prohibited to replace the fuse with copper or iron wire. The size of the fuse must match the power consumption. When replacing the fuse, remove the porcelain box cover to replace it. Do not directly connect the fuse in the porcelain box, and do not replace the fuse when it is live (without opening the knife gate).
(4) After the fuse is blown or the leakage switch is activated, the reason must be identified before the switching power supply can be closed. Under no circumstances should the wire be used to short-circuit the fuse or press the trip mechanism of the leakage switch to forcibly transmit power.
(5) When purchasing household appliances, you should carefully check whether the technical parameters of the product manual (such as frequency, voltage, etc.) meet the local electricity requirements. It should be clear how much power is consumed and whether the existing power supply capacity of the family meets the requirements, especially whether the wiring capacity, plugs, sockets, fuse tools, and electricity meters meet the requirements.
(6) When the household power distribution equipment cannot meet the capacity requirements of household appliances, it should be replaced and reconstructed, and it is strictly forbidden to use it. Otherwise, overloading will damage electrical equipment and may also cause electrical fires.
(7) When purchasing household appliances, you should also understand the insulation performance: whether it is general insulation, reinforced insulation or double insulation. If it is grounded for leakage protection, a ground wire is essential. Even for electrical equipment with reinforced insulation or double insulation, it is beneficial to make protective grounding or zero connection.
(8) Household appliances with electric motors (such as electric fans, etc.) should also understand the heat resistance level and whether they have been running continuously for a long time. Pay attention to the heat dissipation conditions of household appliances.
(9) Before installing household appliances, you should check the requirements of the product manual for the installation environment. Pay particular attention to not installing the household appliances in an environment with humid heat, dust, or flammable, explosive, corrosive gases under possible conditions. .
(10) When laying indoor wiring, the phase and neutral wires should be clearly marked, and be consistent with the wiring of household appliances, and must not be connected to each other.
(11) When connecting household appliances to the power supply, an openable switch or plug connector must be used, and it is forbidden to insert the wire directly into the socket hole.
(12). All household appliances that require protective grounding or security connection to zero should use three-pin plugs and three-eye sockets. Do not use two-pin plugs and two-eye sockets instead, resulting in ground (or zero-connected) wire gaps.
(13) It is better not to have a connector in the middle of the home wiring. When there is a connector, the contact should be firm and wrapped with insulating tape, or use a porcelain junction box. The standard uses medical tape to replace electrical tape to wrap the joint.
(14) The connection between the wire and the switch, knife gate, fuse box, lamp head, etc. should be firm and reliable with good contact. The multi-rubber soft copper wire connector should be twisted together and then placed under the screw gasket of the connector to prevent the thin strands from spreading and touching the other connector to cause a short circuit.
(15). Household wiring shall not be laid directly on flammable building materials. If wiring is required on wood, porcelain beads or porcelain clips must be used; through bushings, porcelain bushings must be used. Do not use flammable plastics and other flammable materials as decorative materials.
(16) Although the grounding or zero-connection line is normally not charged, if the leakage occurs after the wire is disconnected, the power appliance shell will be charged; in the event of a short circuit, the grounding wire will also pass a large current. For its safety, the grounding (zero-connecting) wire specification should not be less than the phase conductor, and no switch or fuse should be installed on it, nor should it have connectors.
(17). The ground wire should not be connected to the water pipe (because the water pipe joints are all insulated with no grounding effect); they must not be connected to the gas pipe (to prevent gas explosion caused by electric sparks); On the ground line of the telephone line (to prevent the strong electricity from weakening the electricity); it must not be connected to the down line of the lightning protection line (to prevent counterattack when there is lightning).
(18) All switches, knife gates, and fuse boxes must be covered. Bakelite covers are aging and incomplete must be replaced. Dirty and damp people must be wiped clean after power off before use.
(19) Do not drag the power cord on the ground to prevent the power cord from tripping and damage the insulation.
(20) Prior to trial use of household appliances, all switches and buttons should be placed in the original stop position according to the instructions, and then operated in the order of opening and stopping required by the instructions. If there are moving parts such as a shaking head fan, sufficient moving space should be considered in advance.
(21) If abnormal conditions such as sparks, smoke or burning smell are found after the household appliances are powered on, they should immediately shut down and cut off the power supply for inspection.
(22) Be sure to cut off the power when moving household appliances to prevent electric shock.
(23) The flammable materials must be kept away from the heating appliances. Heating appliances such as electric stoves, heating stoves, electric irons, etc. must not be placed directly on wooden boards to avoid fire.
(24) It is forbidden to touch the live switch with wet hands; it is forbidden to pull and plug the power plug with wet hands; when pulling and plugging the power plug, your fingers must not touch the metal parts of the contacts; nor can you replace the electrical components or light bulbs with wet hands.
(25) For household appliances that are often used by hand (such as hair dryers, electric irons, etc.), do not use the wire around your hands.
(26) For household appliances that come into contact with the human body, such as electric blankets, electric oil caps, and electric footwear, etc., they should be energized and checked before use, and only after contact with the human body.
(27). It is forbidden to move household appliances by dragging wires; it is forbidden to pull plugs by dragging wires.
(28) When using household appliances, first plug in the socket on the uncharged side, and then close the knife gate or plug in the socket on the live side; when deactivating household appliances, on the contrary, first pull the knife on the live side or pull out the live side Socket, and then pull out the socket on the uncharged side (if unplugged).
(29). In an emergency, if you need to cut off the power wire, you must use insulated electrician pliers or a tool with an insulated handle.
(30) When rescuing an electric shock person, first disconnect the power supply or use a wooden board or an insulating rod to pick up the power cord. Do not drag the electric shock person directly with your hands to avoid continuous electric shock.
(31) In addition to appliances such as refrigerators, household appliances should be turned off at will, especially electric appliances, to prevent fire caused by long-term heat.
(32) It is strictly forbidden to use the bed switch. In addition to electric blankets, do not lead live electrical equipment to bed, close to the sleeping body. Even if you use an electric blanket, if it is not necessary to power on and keep warm all night, it is recommended to use it after the heat is off to ensure safety.
(33), household appliances burn, smoke or catch fire, they must immediately disconnect the power supply, and must not be sprayed with water or foam fire extinguishers.
(34) Insulate the indoor wiring and electrical equipment regularly, and if damaged, wrap it with electrical tape in time.
(35) For household appliances that are not used again for a long time before the rainy season or not used for a long time, the insulation resistance measured with a 500V shake meter should not be less than 1MΩ before the insulation is considered good and can be used normally. If there is no shaking table, at least the electroscope should also be used to frequently check for leakage.
(36) For household appliances that are frequently used, keep them dry and clean, and do not wipe the surface of household appliances with corrosive or conductive liquids such as gasoline, alcohol, soapy water, and decontamination powder.
(37). After the home appliance is damaged, please ask a professional or send it to a repair shop for repair; it is strictly forbidden for non-professionals to open the housing of the home appliance when it is live.