LED display installation engineer must know the electrician common sense
Time:2018-12-26
Views:52
01. Why must the lighting switch be connected to the fire line?
If the lighting switch is installed on the zero line, although the light is not on when it is disconnected, but the phase line of the lamp head is still on, and people think that the light is not on, they will mistakenly think that it is in the state of power failure.In fact, the ground voltage of each point on the lamp is still 220 volts.If people touch these areas that are actually charged when the lights go off, they can cause an electrical shock.So all sorts of illume switch or the switch of equipment of use electricity of single-phase small capacity, connect in series only on fire line, ability ensures safety.
02. How to install single-phase three-hole socket correctly?
In general, single-phase power equipment, especially mobile power equipment, should use a three-core plug and matching three-hole socket.There is a special protection connection zero (ground) jack on the three-hole socket, in the use of connection zero protection, someone often only at the bottom of the socket will be this hole wiring pile head and lead into the socket directly connected to the zero line, which is very dangerous.In case the zero line of the power supply is disconnected, or the fire (phase) line and zero line of the power supply are connected in the opposite direction, the metal parts such as the shell will also carry the same voltage as the power supply, which will lead to electric shock.
Therefore, special grounding jack should be connected with special protective grounding wire when wiring.When adopting the zero-connection protection, the zero-connection line should be drawn from the power supply end specially, and should not be nearby to use the zero-connection that leads into the socket.
03. Why is plastic insulated wire strictly prohibited to be buried directly in the wall?
(1) after the plastic insulated wire is used for a long time, the plastic will age and crack, and the insulation level will be greatly reduced. When the line is overloaded or shorted for a short time, it is easier to accelerate the damage of insulation.
(2) once the wall is damp, it will cause a large area of electricity leakage, endangering personal safety.
(3) the plastic insulated wire is directly buried in the ground, which is not conducive to the maintenance and repair of the line.
Why use leakage protector?
Leakage protector, also known as leakage protection switch, is a new type of electrical safety device, its main purpose is:
(1) prevent electric shock accidents caused by leakage of electric equipment and electrical lines.
(2) prevent single-phase electric shock accidents in the process of power utilization.
(3) timely cut off single-phase grounding fault in the operation of electrical equipment to prevent electrical fire accidents caused by leakage of electricity.
(4) with the improvement of people‘s living standard, increase of all kinds of electrical appliances, in the process of electricity, due to the defect, improper use of electrical equipment and safety technical measures against the person get an electric shock and fire accident caused, has brought people‘s lives and property losses should not have, and the occurrence of leakage protector, to prevent the happenings of all kinds of accidents, to cut off the power supply in time, to protect equipment and personal safety, provides a reliable and effective technical measures.
05, what is the main cause of 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 a high-voltage line, climb a high-voltage pole and dig out the bird‘s nest;After the low-voltage overhead line is broken, use your hands to pick up the fire line without power failure;Live wiring at night hand touch live body;Touch the broken rubber cover with your hand.
(2) violation of operating procedures, live connection lines or electrical equipment without taking necessary safety measures;Touching damaged equipment or wiring;Mistakenly boarding live equipment;Electrically connected lighting fixtures;Electric tools for repair on line;Live moving electrical equipment;Twist the bulb with a wet hand, etc.
(3) unqualified equipment and insufficient safety distance;Excessive grounding resistance of two-wire and one-earth system;The grounding wire is unqualified or disconnected;Insulation damage wire exposed, etc.
(4) the equipment is out of repair, and the circuit is broken or the pole is knocked down by strong wind without timely repair;Failure to timely change the bakelite damage of the rubber cover brake;Motor wire damage, so that the shell long live;The porcelain bottle is damaged, so that the phase line and the cable are short, and the equipment shell is charged.
(5) for other accidental reasons, walking at night breaks the live wires falling on the ground.
06. What rescue measures should be taken in case of electric shock?
When an electric shock occurs, while ensuring the safety of the rescuer himself, it is necessary to first try to make the victim quickly disconnect from the power supply, and then carry out the following emergency repair work.
(1) remove tight clothing that prevents the person from breathing.
(2) check the oral cavity of the electrocuted person and clean the mucus in the oral cavity. If there are dentures, remove them.
(3) immediate and on-site rescue, such as respiratory arrest, the use of mouth-to-mouth artificial respiration rescue, if the heart stops beating or irregular vibration, artificial chest extrusion rescue.Never interrupt without reason.
If a second person is present, in addition to the rescuer, the following should also be done immediately:
1) provide first-aid tools and equipment.
2) persuade the on-site miscellaneous personnel to return.
3) keep sufficient lighting and air circulation on site.
4) report to the leader and ask the doctor to come to the rescue.
Experimental studies and statistics show that 90% of patients can be saved if they are treated from 1 minute after electric shock.If the rescue begins 6 minutes after the shock, there is only a 10% chance of survival.And from electric shock 12 minutes after the rescue, the possibility of survival is very small.Therefore, when someone is found to be electrocuted, should race against time, using all possible means.
07, what measures are there to use electricity safely on the display screen?
With the popularization and application of LED display screen, it is very important to master the knowledge of safe electricity consumption and ensure the safety of electricity consumption.
(1) don‘t buy fake and inferior products of "three nos".
(2) there should be a complete and reliable power cord plug when using electricity.Grounding protection shall be applied to all electrical equipment with metal shell.
(3) switches and fuses cannot be installed on ground and zero wires.It is forbidden to connect the grounding wire to the tap water and gas pipelines.
(4) do not touch live equipment with wet hands, and do not wipe live equipment with a wet cloth.
(5) do not pull and connect wires randomly, and do not move live equipment randomly.
(6) disconnect the power supply before inspecting and repairing the electrical appliances on the LED large screen.
(7) when the power cord of the electric appliance is damaged, it should be replaced immediately or wrapped with insulating cloth.
(8) in case of fire of electrical appliances or wires, disconnect the power supply before extinguishing the fire.
08. How to prevent burning and damaging the electrical equipment on the display screen?
The rated voltage of the input line of the switching power supply of the commonly used LED display screen is 220 volts, and the normal supply voltage is about 220 volts.When the power supply line due to lightning and other natural disasters caused by the instantaneous increase of power supply voltage, three-phase load imbalance household line out of repair occurs zero line, or due to human error caused by phase voltage rise and other reasons such as voltage rise, it will make the current increase in the screen power supply due to overheating and burn.
To prevent the burning of power supply and other electrical appliances, it is necessary to start from the following aspects: first, when the electrical equipment is not used, it should be disconnected from the power supply as far as possible;The second is to transform the old disrepair wiring;The third is to install leakage switch with overvoltage protection.
09, what is the basic requirements of leakage protector?
Technically, it should meet the following requirements:
(1) the sensitivity of electric shock protection should be correct and reasonable. Generally, the starting current should be within the range of 15-30 ma.
(2) the action time of electric shock protection should not be more than 0.1 seconds in general.
(3) the protector shall be equipped with necessary monitoring equipment to prevent it from losing its protective effect when the operating state changes. For example, the zero-wire grounding device shall be installed for the voltage type electric shock protector.
10. How to prevent electrical fire accidents?What happens after a fire?
First of all, when installing electrical equipment, must ensure the quality, and should meet the requirements of safety and fire prevention.To use qualified electrical equipment, the damaged switch, lamp holder and damaged wire can not be used, the wire joints should be firmly connected in accordance with the specified connection method, and wrapped with insulation tape.Tighten the screws on the connection of pile head and terminals to prevent poor contact due to loose connection.Electrician installed equipment, does not mean that you can once and for all, the user in the process of use, such as found lamp head, socket wiring loose (especially mobile electrical plug wiring easily loose), poor contact or overheating phenomenon, to find electrician timely treatment.
Secondly, do not place oil, cotton, wood chips, wood and other easily dyed articles near low-voltage lines and switches, sockets, fuses.
Before electric fire, have a kind of augural, want to cause take seriously especially, because overheat of electric wire can burn insulation skin above all, send out a kind of bad smell that burns rubber skin, burn plastic.So, when smelling this odour, should think of possibility is electric respect reason causes above all, if cannot check other reason, should pull brake to cut off power immediately, until find out the reason, after proper processing, ability closes switch send power.
In case of a fire, regardless of whether it is caused by electrical aspects, the first thing to do is to find a way to quickly cut off the power within the scope of the fire.Because, if the fire is caused by electrical, cut off the power supply, also cut off the source of fire;If the fire is not caused by the electrical side, it will also burn out the insulation of the wire, if the power is not cut off, the burnt wire will cause a short circuit, causing a wider range of wire fire.In the event of electrical fire, cover soil, cover sand or fire extinguisher should be used, but never use foam fire extinguisher, so the kind of extinguishing agent is conductive.
11, engineering safety electricity common sense
(1) each construction unit must have some necessary electrical appliances, such as a test pen, screwdriver, plastic pliers, etc., but also must have the right to use screen electrical appliances with a variety of specifications of fuse and fuse.
(2) each screen user must be equipped with a total insurance, a total knife brake and a leakage protection switch.
(3) under no circumstances is it allowed to replace the fuse with copper or iron wire.The size of the fuse must match the power capacity.When replacing the fuse, remove the cover of the porcelain box and replace the fuse. Do not overlap the fuse directly in the porcelain box.
(4) after the fuse is blown or the leakage switch operates, the reason must be found out before switching on the power supply.Under no circumstances shall the safety stub or the trip mechanism of the leakage switch be forced to send power by wires.
(5) when purchasing screen appliances, please carefully check whether the technical parameters (such as frequency, voltage, etc.) in the product specification meet the local electricity requirements.It is necessary to know how much power is consumed and whether the existing power supply capacity of users meets the requirements, especially whether the wiring capacity, plug, socket, fuse and electricity meter meet the requirements.
(6) when the power distribution equipment used for the screen cannot meet the capacity requirements of the overall electrical appliances used for the display screen, it shall be replaced and transformed, and it is strictly prohibited to make do with it.Otherwise, overload operation will damage electrical equipment and may cause electrical fire.
(7) to buy screen appliances should also understand their insulation performance: general insulation, reinforced insulation or double insulation.If the leakage protection is based on grounding, grounding wire is essential.Even for electrical equipment with reinforced insulation or double insulation, protective grounding or zero connection is beneficial.
(8) screen appliances with motors (such as exhaust fans, air conditioners, etc.) should also be aware of the heat resistance level and whether they run continuously for a long time.Pay attention to the heat dissipation conditions of electrical appliances.
(9) before installing the screen appliance, please check the requirements of the product manual for the installation environment, especially pay attention to the possible conditions, do not install the screen appliance in the hot and humid, dust or flammable, explosive, corrosive gas environment.
(10) when wiring in the laying screen, the phase line and zero line shall be clearly marked, and shall be consistent with the wiring of the electrical equipment in the screen, and shall not be misconnected with each other.
(11) when the screen appliance is connected to the power supply, a dismountable switch or connector must be used. It is forbidden to directly insert the wire into the socket hole.
(12) where there is a requirement for the protection of grounding or security zero screen electrical appliances, should use three-pin plug and three-eye socket, not with both feet plug and double eye socket substitute, resulting in grounding (or zero) line gap.
(13) it is better to have no connector in the middle of screen wiring.Connections must be made firmly in contact and wrapped with insulating tape, or with porcelain junction boxes.Use medical tape instead of electrical tape to wrap the joint.
(14) the connection between wire and switch, knife brake, safety box and lamp holder should be firm and reliable with good contact.Multi-glue soft copper wire joint should be twisted together and then put under the joint screw gasket to prevent the thin strands of wire from spreading and touching the other joint to cause a short circuit.
(15) the wiring of the project of the display screen shall not be directly laid on inflammable building materials. Porcelain beads or porcelain clips must be used for wiring on wood;Porcelain casings must be used to cross the board.Inflammable plastics and other inflammable materials shall not be used as decorative materials.
(16) although the ground or zero wire is normally not energized, if the wire is broken and leakage occurs, the shell of the power appliance will be energized;In case of short circuit, the grounding wire also passes through a large current.For its safety, the specification of grounding (zero connection) wire shall not be less than that of phase conductor, and no switch or fuse shall be installed on it, and no connector shall be provided.
(17) the grounding wire shall not be connected to the tap water pipe (because the tap water pipe joints are now sealed with insulation tape, there is no grounding effect);Do not connect to the gas pipe (in case the spark causes gas explosion);Not connected to the ground wire of the telephone line (in case of strong electricity channeling weak electricity);It shall not be connected to the lead wire of the lightning conductor (in case the lightning strikes back).
All switches, knives and safes must be covered.Bakelite cover plate aging, incomplete must be replaced.Dirty dampness person must cut off power to wipe clean hind can use.
(19) do not drag the power cord onto the ground to prevent it from tripping and damaging the insulation.
(20) all switches and buttons should be placed in the original stop position according to the instruction manual before the trial of the screen appliances, and then operate in the operation sequence required by the instruction manual.If moving parts are available, sufficient space for movement should be considered in advance.
(21) when sparks, smoke or burning smell are found after the power on the display screen is energized, it shall immediately stop the machine and cut off the power supply for inspection.
(22) power supply must be cut off to avoid electric shock when moving display screen appliances.
(23) keep flammable materials away from heating appliances.The electric appliance that gives off heat (be like power source) must not put on board directly, lest cause fire.
(24) do not touch the live switch with wet hands;Do not use wet hands to pull out or insert power plug;Fingers shall not touch the metal part of the contact when unplugging or inserting the power plug;Do not replace electrical components or bulbs with wet hands.
(25) for frequently used electrical appliances (such as hair dryer, soldering iron, etc.), do not use the wire wound in the hand.
(26) for electrical appliances in contact with human body, such as electric soldering iron, should be energized before use to check the test, there is no leakage of electricity before contact with human body.
(27) it is prohibited to move the power supply by dragging the wire;It is forbidden to pull the plug by pulling the wire.
(28) when using screen appliances, plug in the socket on the uncharged side first, and then close the knife brake or plug in the live side socket;On the other hand, pull open the live side knife brake or pull out the live side socket before pulling out the unlive side socket (if necessary).
(29) when the power supply wire needs to be cut off in an emergency, insulated electrician‘s pliers or cutting tools with insulated handle must be used.
(30) when rescuing electric shock personnel, first of all, disconnect the power supply or pick up the power cord with wooden boards and insulating rods. Do not directly drag the electric shock personnel with your hands to avoid serial electric shock.
(31) in addition to air conditioning and other electrical appliances, screen appliances should be conveniently turned off power supply, especially electrical heating appliances, to prevent fire caused by long time heat.
(32) if the screen appliance is burning, smoking or catching fire, it must be immediately disconnected from the power supply and must not be sprayed with water or foam fire extinguisher.
(33) regular insulation inspection shall be carried out on wiring and electrical equipment in the screen. If any damage is found, it shall be wrapped with electrical adhesive cloth in time.
(34), or for a long time before the rainy season need not again use display, 500 v shaking table was used to measure the insulation resistance shall be not less than 1 m Ω, may think that the insulation is good, can be normal use. If no shaking table, or at least application test pen check whether leakage phenomenon.
(35) for frequently used electrical equipment on the display screen, should keep it dry and clean, do not use gasoline, alcohol, soapy water, detergent and other corrosive or conductive liquid wipe the surface of electrical appliances.
(36) professional personnel shall be invited to repair the damaged screen appliances;It is strictly prohibited for non-professionals to open the electrical shell for LED display screen when it is live.
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