1. Why does the light switch need to be connected to the live wire?
If the light switch is installed on the neutral line, even if the light does not turn on when turned off, the phase line of the lamp head will still be connected and People will mistakenly think that the light does not turn on and is out of power. In fact, the ground voltage at each point of the lamp is always a dangerous 220 volts. If people touch these live parts when the lights are off, an electric shock accident will occur. Therefore, various small-capacity single-phase light switches or electrical equipment switches can only ensure safety if connected in series on the live wire.
2. How to properly install the three-hole single-phase socket? For what?
As a general rule, single-phase electrical equipment, particularly electrical equipmentMobile electrical equipment, must use three-conductor plugs and corresponding three-hole sockets. There is a dedicated protective zero (ground) plug on the three-hole socket. When using zero protection, some people often only connect the wiring head of this hole at the bottom of the socket to the neutral wire inserted into the socket. is extremely dangerous. Because if the neutral wire of the power supply is disconnected, or the live wire (phase) and the neutral wire of the power supply are connected backwards, the metal parts such as the case will also carry the same voltage as power supply, causing an electric shock.
Therefore, the dedicated earth socket must be connected to the dedicated protective earth wire when wiring. When using zero connection protection, the neutral wire should be specially routed from the power end instead of using the neutral wire inplugged into a nearby outlet.
3. Why is it strictly forbidden to bury plastic insulated wires directly into walls?
(1) After long-term use of plastic insulated wires, the plastic will age and crack, and the insulation level will be greatly reduced when the line is overloaded or short-circuited for a short time period. it is easier to accelerate damage to the insulation.
(2) Once the wall becomes wet, it will cause large area leakage and endanger personal safety.
(3) Plastic insulated wires are directly buried, which is not conducive to line inspection and maintenance.
4. Why Use a Leak Protector?
Leakage protector, also known as leakage protection switch, is a new type of electrical safety device. Its main uses are:
(1) Prevent electrical leakage caused by electrical equipment. and electrical circuits.
(2) Prevent single-phase electric shock accidents during electricity use.
(3) Timely cut off single-phase ground faults during the operation of electrical equipment to avoid electrical fires caused by leakage.
(4) With the improvement of people's living standards and the continuous increase in the number of household appliances, when using electricity, personal electric shock and accidents are caused by defects in the electrical equipment itself, improper use. and unfavorable technical security measures. Fire accidents have led to unjustified loss of life and property, and the emergence of leak protection devices has provided reliable and effective technology to prevent the occurrence of various accidents.ents, cut off the power supply in time, and protect equipment and equipment. personal safety.
5. What are the main causes of electric shock accidents?
Statistics show that the main reasons for electric shock accidents are:
(1) Lack of knowledge of electrical safety, flying kites nearby power lines, climbing high voltage poles to dig up bird nests; picking up live wires with hands without power interruption past low-voltage overhead lines; are disconnected; touching live wires with hands in the darkness of the body; touch the damaged rubber cover of the knife gate with your hands.
(2) Violating operating procedures, connecting live electrical lines or equipment without taking necessary safety measures; touch ofs damaged equipment or wires; connect live lighting devices; Energized mobile electrical equipment; Use wet hands to twist bulbs, etc.
(3) The equipment is not qualified and the safety distance is not sufficient; the grounding resistance of the two-wire-one-ground system is too large; the ground wire is not qualified or the insulation is disconnected; the wire is exposed, etc.
(4) The equipment is in poor condition, and strong winds have cut the lines or toppled the poles and they have not been repaired in time; the bakelite of the rubber cover of the knife holder was damaged and was not changed; with time ; the motor wires were damaged, leaving the hull charged for a long period of time; the porcelain bottle has been damaged, causing the phase wire and traction wire to be short circuited, and the equipment shell is loaded.
(5) Other reasons acincidents, walking at night and touching broken live wires on the ground.
6. What emergency measures should be taken in case of electric shock?
When an electric shock accident occurs, while ensuring the safety of the rescuer himself, the rescuer must first try to quickly turn off the power to the person who received the electric shock, then perform the following emergency response. repairs.
(1) Remove tight clothing that restricts the electrocuted person's breathing.
(2) Check the mouth of the person who received an electric shock, clean the mucus in the mouth, and remove dentures if there are any.
(3) Immediate rescue on site. If breathing stops, use mouth-to-mouth artificial respiration. If the heart stops beating or shakes irregularly, artificial chest compression may be used. It should not be interrupted without reason.
If there is a second person present on the scene in addition to the first aid worker, the following work must be carried out immediately:
1) Provide first aid tools and equipment.
2) Discourage inactive personnel from leaving the premises.
3) Keep the site with adequate lighting and air circulation.
4) Report to the leader and ask for a doctor to come to the rescue.
Experimental research and statistics show that if treatment starts 1 minute after electric shock, 90% of people can be saved; if treatment begins 6 minutes after the electric shock, there is only a 10% chance of recovery. survival; If you start resuscitation 12 minutes after the electric shock, the possibility of resuscitation is extremely low. Therefore, when you find someone being electrocuted, you must race against time and use all possible methods.
7. What steps can be taken to use electricity at home safely?
With the popularization of household appliances, it is crucial to correctly master the knowledge of safe electricity use and ensure the safety of electricity use.
(1) Do not buy counterfeit and poor quality household products with the “Three Nos”.
(2) When using household appliances, there must be a complete and reliable power cord plug. Appliances with metal housings must be grounded for protection.
(3) Cannot be presentInstall switches and fuses on ground and neutral lines. It is prohibited to connect the ground wire to tap water or gas pipes.
(4) Do not touch live equipment with wet hands or wipe live equipment with adamp cloth.
(5) Do not connect wires indiscriminately or move live equipment casually.
(6) When inspecting and repairing household appliances, the power supply must first be disconnected.
(7) When the power cord of a household appliance is damaged, it should be replaced immediately or wrapped in an insulating cloth.
(8) When a fire occurs in household appliances or wires, the power supply should be disconnected before extinguishing the fire.
8. How to prevent appliances from burning?
The rated voltage of commonly used household appliances is 220 volts, and the normal supply voltage is around 220 volts. Voltage surge occurs when the supply voltage in the power line increases instantly due to natural disasters such as few, the three-phase load is unbalanced and the household line is in poor condition for a long time and the neutral line is broken, or the phase voltage increases due to human improper wiring, etc., which will increase power and will cause appliances to burn out due to overheating. To prevent household appliances from burning, we should start from the following aspects: first, try to disconnect the power supply when the electrical equipment is not in use; second, modify old and dilapidated household wiring; third, install a leakage switch with surge; protection.
9. How to choose fuses for residential use?
Fuses used in residential homes should be selected based on electrical capacity. For example, when using an electric meter with a capacity of 5 A, the fuse must be sugreater than 6 A and less than 10 A; if you use an electric meter with a capacity of 10A, the fuse should be greater than 12A and Less than 20A, that is, the selected fuse should be 1.2~ of the meter capacity electric 2 times. The selected fuse must comply with regulations, and multiple small capacity fuses cannot be used together, nor can copper wires be used instead of fuses.
10. What are the basic requirements for leak protection devices?
Technically, the following requirements must be met:
(1) The sensitivity of the protection against electric shock must be correct and reasonable. Generally, the starting current should be around 15. ~30 mA.
(2) The action time of protection against electric shock should generally not be more than 0.1 seconds.
(3) The protector must be equipped with monitoring equipmentlaunches necessary to avoid loss of protection when the operating state changes. For example, for voltage type electric shock protectors, a neutral grounding device must be installed.
11. How to prevent electrical fire accidents? What to do after a fire?
First of all, when installing electrical equipment, quality must be guaranteed and all safety and fire protection requirements must be observed. Qualified electrical equipment must be used. Damaged switches, lamp holders and wires cannot be used. The wire joints should be firmly connected according to the prescribed connection method and wrapped with insulating tape. Tighten the screws on the pile heads and wiring terminals to avoid poor contact due to loose wiring. Once the electrician has installed the equipment, it does not mean that it can be done aonce and for all. During use, if the user finds the lamp holder, if the socket wiring is loose (especially the socket wiring of mobile electrical appliances is easy to loose), if there is poor contact or overheating, please find an electrician to handle it in time.
Second, do not place oil, cotton, sawdust, wood and other easy-to-stain items near low-voltage lines, switches, sockets and fuses .
Before an electrical fire, there is a precursor to which special attention should be paid. That is, the outer insulating coating of the wire will first be burned due to overheating, giving off an unpleasant smell of burning rubber and burning plastic. Therefore, when you smell this smell, you should first think that it may be caused by electrical reasons. If no other reason can be found, you mustimmediately turn off the power and turn off the power until the cause is discovered and properly treated. before turning off the power supply.
In the event of a fire, whether caused by electricity or not, you must first find a way to quickly shut off the electrical power to the fire area. Because if the fire is caused by electrical aspects, cutting off the electrical supply will also cut off the source of the fire; if the fire is not caused by electrical aspects, the insulation of the wires will also be burned; If the wires are not cut, the burned wires will cause the contacting wires to short circuit, causing a wider range of wires to catch fire. After an electrical fire occurs, cover it with earth, sand or a fire extinguisher, but foam extinguishers should not be used, so this extinguishing agent is conductive.
12. Common sense for safe use ofelectricity at home
(1) Every family should have some necessary electrical tools, such as electrical test pens, screwdrivers, glue pliers, etc. ., and must also have various specifications of fuses and fuses suitable for use in household appliances.
(2). Each household must be equipped with a main fuse in front of the electric meter, and a main switch and a leakage protection switch behind the electric meter.
(3). It is strictly forbidden to use copper or iron wire in place of a fuse, under any circumstances. The size of the fuse must match the electrical capacity. When replacing the fuse, you need to remove the porcelain box cover and replace it. Do not connect the fuse directly into the porcelain box. Do not replace the fuse when the device is powered on (without openingir the knife switch).
(4) Once the fuse is blown or the leakage switch is tripped, the cause must be found before the switching power supply can be turned on again. Under no circumstances should a wire be used to short the fuse or depress the leakage switch trip mechanism to force power transmission.
(5) When purchasing household appliances, you should carefully check whether the technical parameters (such as frequency, voltage, etc.) contained in the product manual meet local requirements regarding electricity. It is necessary to know how much energy is consumed and whether the existing power supply capacity of the house meets the requirements, particularly whether the wiring capacity, plugs, sockets, fuses and meters meet the requirements .
(6) When the household power distribution equipment cannot meet thecapacity requirements of household appliances, it must be replaced and modified, and improvised use is strictly prohibited. Otherwise, overload operation will damage electrical equipment and may also cause an electrical fire.
(7) When purchasing household appliances, you should also understand its insulation performance: whether it is general insulation, reinforced insulation or double insulation. If leak protection relies on grounding, a ground wire is essential. Even for electrical equipment with reinforced insulation or double insulation, it is also beneficial to have protective earthing or protective zero connection.
(8) For household appliances with electric motors (such as electric fans, etc.), you also need to know the thermal resistance level and whether they can functionoperate continuously for a long time. Pay attention to the heat dissipation conditions of household appliances.
(9) Before installing household appliances, you should check the product instructions for installation environment requirements. Take particular care, if possible, not to install household appliances in a hot, humid, dusty or flammable or explosive location. locations, corrosive gas environment.
(10). When laying indoor wiring, phase lines and neutral lines should be clearly marked and consistent with the wiring of household appliances, and should not be incorrectly connected.
(11) Household appliances must be connected to the power supply using switches or connectors that can be unplugged. Direct insertion of wires into socket holes is prohibited.
(12).All apSuch appliances that require protective earthing or a safety zero connection must use three-prong plugs and three-prong sockets instead, which will cause problems. grounding (or zero connection).
(13). It is best not to have joints in the middle of household wiring. Where joints are required, they should be firmly contacted and wrapped with electrical tape, or use a porcelain junction box. It is recommended to use medical tape instead of electrical tape to wrap joints.
(14) The connection between wires and switches, knife switches, fuse boxes, lamp holders, etc. must be firm and reliable, with good contact. Multi-glue soft copper wire connectors should be twisted together then placed under the screw joint of the connector to prevent the thin strands from spreading and hitting un other connector and cause a short circuit.
(15) Household wiring should not be laid directly on flammable building materials. If you must wire on wood, you must use porcelain beads or porcelain clips to pass through wooden planks. Plastics and other flammable materials should not be used as decorative materials.
(16) Although the ground or neutral wire is not charged normally, if there is leakage after disconnection, the shell of the electrical appliance will charge in the event of a short circuit , a large current will flow through; the earth wire. For safety reasons, the size of the ground (neutral) wire should not be smaller than that of the phase conductor, and no switches or fuses should be installed in it, and there should be no connectors.
(17). The ground wire should not be connected to the water pipe (because the current joints of thewater pipes are plugged with insulating tape, which has no grounding effect, it should not be connected to gas); hose (to avoid sparks) It may cause a gas explosion); it must not be connected to the ground wire of the telephone line (to prevent strong electricity from channeling weak electricity); it must not be connected to the down conductor of a lightning rod); protective wire (to prevent counter-attacks during lightning).
(18). All switches, knife switches and fuse boxes must have covers. Aged or incomplete bakelite lids should be replaced. If it is dirty or wet, it should be wiped dry before use.
(19) Do not drag the power cord across the floor to avoid tripping over the power cord and damaging the insulation.
(20) Before trying household appliances, you should refer to the instructions, placePlace all switches and buttons in the original off position, then operate according to the start and stop sequence required by the instructions. If there are moving parts such as oscillating fans, sufficient space for movement should be provided in advance.
(21), household appliances are turned onIf an abnormality such as sparks, smoke or burning smell is detected, immediately stop the machine and turn off the power supply for inspection.
(22). Be sure to turn off the power supply when moving household appliances to avoid electric shock.
(23). Flammable materials should be kept away from heating appliances. Electric stoves, heating pans, electric irons and other heating appliances should not be placed directly on wooden boards to avoid the risk of fire.
(24). HeIt is forbidden to touch the live switch with wet hands; it is prohibited to remove or plug in the power plug with wet hands; remove or plug in the power plug; nor use wet hands to replace electrical components or bulbs.
(25). For household appliances often used by hand (such as hair dryers, soldering irons, etc.), do not wrap the wire around your hand.
(26). For household appliances that come into contact with the human body, such as electric blankets, electric oil caps, electric heating shoes, etc., they should be turned on and tested before use to ensure that they do not There is no leak before contacting the human body.
(27) It is prohibited to move household appliances by pulling wires; It is prohibited to remove plugs by pulling wires.
(28) When youuse household appliances, plug in the socket on the non-powered side first, and finally close the switch or plug in the socket on the powered side, do the reverse; , first open the plug on the powered side knife switch or unplug the plug on the live side, then unplug the plug on the non-powered side (if necessary).
(29). When it is necessary to cut the power wire in an emergency, insulated electrician's pliers or tools with insulated handles should be used.
(30) When rescuing an electric shock victim, first disconnect the power supply or use a wooden board or insulating rod to open the power cord. Do not drag the electric shock victim directly with your hands to avoid the chain. electric shocks.
(31). With the exception of appliances such as refrigerators, household appliances should be turned off easily, especiallyr electric heaters, to avoid long-term heating and fires.
(32). It is strictly prohibited to use the bed switch. Except for electric blankets, do not bring live electrical equipment to bed or near the sleeping human body. Even if you use an electric blanket, if it is not necessary to keep warm all night, it is recommended to turn off the power after heating to ensure safety.
(33) If household appliances are burned, smoking or on fire, the power supply must be immediately cut off and water or foam extinguishers must not be sprayed.
(34) Inspection of the insulation of indoor wiring and electrical equipment should be carried out regularly, and any damage should be wrapped with insulating tape in time.
(35). For household appliances that have been reused before saleisation from rain or which have not been used for a long time, the insulation resistance measured with a 500 V megohmmeter should not be less than 1 MΩ before it can be used. considered well insulated and can be used normally. If a megger is not available, at least use an electrical test pen to regularly check for leaks.
(36). Keep frequently used appliances dry and clean. Do not wipe the surface of household appliances with corrosive or conductive liquids such as gasoline, alcohol, soapy water and detergent powder.
(37). If the household appliances are damaged, please call a professional. Please contact a technician or send it to a repair shop for repair; Non-professionals are strictly prohibited from opening the casing of live household appliances.
5. Principles of safe electric useElectricity
(1) Do not approach objects charged with high voltage (outdoors, high voltage lines, next to transformers) and do not touch objects charged with low voltage. ?
(2) Do not turn the switch with wet hands to insert or remove the plug. ?
(3) When installing and repairing electrical appliances, you must wear insulated shoes, stand on the insulation, and turn off the power supply. ?
(4) It is prohibited to use copper wire instead of a fuse, and it is prohibited to use rubber glue instead of electrical insulating tape. ?
(5) Install an electric shock protector in the circuit and check its sensitivity regularly. ?
(6) During thunderstorms, do not use radios, VCRs and televisions, and unplug the power plugs and TV antenna plugs. Do not use the phone temporarily. If youneed to use it, use the hands-free function. ?
(7) Connecting wires without permission is strictly prohibited, and students are prohibited from using electric stoves, “heaters” and other electrical appliances in the dormitory. ?
(8) Do not fly kites or play ball games under baskets or electrical wires.
6. Other precautions
The safe voltage for humans is not more than 36 volts
Do not touch the metal rod of the pen tip when using the test. pen
< p>High-power electrical appliances must be groundedDo not use your body to connect the live wire and ground wire
The total power of the electrical appliance used cannot be too high, otherwise it will cause excessive current and cause a fire.
When someone receives an electric shockue, do not use your body to pull it. You must immediately turn off the main switch and then. use a dry wooden stick to separate the person from the wire