1. Why the lighting switch must be connected to the live wire?
If the lighting switch is installed on the neutral wire, although the light is not light when disconnected, the live wire of the lamp is still connected, and people think that the light is not bright, it will be mistaken for the state of power failure. In fact, the ground voltage at each point on the luminaire is still a dangerous voltage of 220 volts. If the lights go out when people touch these actually charged parts, it will cause an electric shock accident.
So a variety of lighting switches or uniphase small-capacity electrical equipment switches, only string connected in the live wire, to ensure safety.
2, uniphase three hole socket How to install the correct?
Usually, uniphase electric equipment, especially mobile electric equipment, should use three-core plugs and matching three-hole sockets. The three-hole socket has a dedicated protection neutral (ground) jack, in the use of neutral protection, it is often only in the bottom of the socket to connect the hole in the socket with the plug in the neutral wire directly connected, which is extremely dangerous.
Because if the power supply of the neutral -wire disconnect, or the power of the live(phase) wire, neutral wire connection, the shell and other metal parts will also bring the same voltage as the power supply, which will lead to electric shock. Therefore, the special grounding jack should be connected with the dedicated protective grounding wire.
With neutral protection, the neutral wire should be specially drawn from the power supply, and should not be used near the neutral wire of the socket.
3. Why is the plastic insulated conductor prohibited to be buried directly in the wall?
(1) plastic insulated wire after a long period of use, plastic aging cracking, insulation level greatly reduced, when the wire short overload or short-circuit, more easily accelerate insulation damage.
(2) Once the wall is damp, it will cause large area leakage, endanger personal safety.
(3) The plastic insulated conductor is buried directly, which is not conducive to the maintenance and repair of the wire.
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 accident caused by leakage of electrical equipment and electric circuit.
(2) Prevent uniphase electric shock accident in the process of electricity consumption.
(3) Timely cut off the electrical equipment in the operation of Single-Phase grounding fault, to prevent leakage caused by electrical liveaccident.
(4) With the improvement of people's living standards, all kinds of electrical appliances continue to increase, in the process of electricity consumption, the personal electric shock and liveaccident caused by the defects of the electrical equipment, improper use and safe technical measures bring the people's life and property to an undue loss, and the emergence of the leakage protector to prevent the occurrence of all kinds of accidents, to cut off power, protect equipment and personal safety in time, and provide reliable and effective technical means.
5. What is the main cause of electric shock accident?
Statistical data show that the main causes of electric shock accidents are as follows:
(1) Lack of knowledge of electrical safety, flying kites near high-voltage wires, climbing high voltage poles to dig the nest; low-voltage overhead wire without power failure with hands to pick up the live wire; Night Live electric wiring touch charged body, touch the broken plastic cover breaker
(2) in violation of operating procedures, live connection wires or electrical equipment without taking the necessary safety measures, touching the damaged equipment or wires, mistakenly boarding live equipment, live connected lighting fixtures, live electric repair power tools, live mobile electrical equipment, wet hand twist bulb, etc.
(3) The equipment is unqualified, the safe distance is not enough, the grounding resistance of the second wire is too large, the grounding wire is unqualified or the grounding wire is disconnected, and the conductor is exposed.
(4) The equipment is in disrepair, the wind blows off the wire or blew down the pole not to be repaired in time; the bakelite damage of the rubber cover breaker gate is not changed in time; The motor conductor is damaged so that the shell is charged for a long time;
(5) Other accidental reasons, night walk touch the ground of the live wire.
6. What ambulance measures should be taken when electric shock occurs?
In case of electric shock, in order to ensure the safety of the ambulance at the same time, must first try to make the electric shock quickly out of power, and then carry out the following repair work.
(1) untie the tight clothes that hinder the breath of the electric shock.
(2) Check the mouth of the electric shock, clean the mucous of the mouth, if have dentures, then remove.
(3) Immediate rescue on the spot, such as the cessation of breathing, using mouth-to-mouth resuscitation, if the heart stops beating or irregular fibrillation, can be carried out artificial chest extrusion method Rescue.
Must not be interrupted for no reason.
If there is a second person present in addition to the ambulance at the scene, the following should be done immediately:
1 provide first aid tools and equipment.
2) to persuade the scene Shing.
3 Maintain adequate lighting at the scene and maintain air circulation.
4 Report to the leader and ask the doctor to come to the rescue. Experimental research and statistics show that if the treatment from 1 minutes after the electric shock, then 9neutral % can be revived, if the rescue from 6 minutes after the shock, only 1neutral % of the opportunity to revive, and from the shock after 12 minutes to rescue, the possibility of survival is very small.
So when you find someone is electrocuted, you should race against the clock and use all possible means.
7, LED signs
safe electricity measures?
With the popularization of the application of LED signs, it is very important to correctly master the knowledge of safety electricity and ensure the safety of electricity.
(1) Do not buy "three without" fake and inferior products.
(2) The use of electricity should be a complete and reliable power cord plug.
Earthing protection is applied to the electrical equipment of the metal casing.
(3) cannot install the switch and the fuse on the ground wire and the neutral wire.
It is forbidden to connect the grounding wire to the tap water and gas pipe.
(4) Do not use wet hand contact with live equipment, do not use wet Bushi to wipe live equipment.
(5) Do not randomly pull wires, do not casually move live equipment.
(6) When inspecting and repairing the electrical apparatus on the LED large screen, the power must be disconnected first.
(7) When the power cord of the electrical appliance is damaged, it should be replaced immediately or wrapped with an insulating cloth.
(8) When a liveoccurs in an electrical or electric wire, the power should be disconnected before extinguishing.
8, how to prevent burning led signs on the electrical equipment?
Commonly used LED signs switching power supply the rated voltage is 220 volts, the normal supply voltage of about 220 volts. When the power supply wire is caused by natural disasters such as lightning, instantaneous increase in supply voltage, three-phase load imbalance in the years of disrepair broken neutral wires, or due to man-made fault wiring, such as the rise in voltage, and other causes of voltage rise, will make the current increase in the power supply caused by overheating and burning loss.
To prevent burning power and other electrical devices, it is necessary to start from the following: First, the use of electrical equipment should be as far as possible disconnect the power supply; the second is to reconstruct the old dilapidated wiring; the third is to install with overvoltage protection leakage switch.
9. What is the basic requirement of leakage protector?
The following requirements should be met technically:
(1) The sensitivity of electric shock protection should be correct and reasonable, the general starting current should be within the range of 15~30 Ma.
(2) The action time of electric shock protection should not be greater than neutral .1 seconds under normal circumstances.
(3) The Protector shall be equipped with the necessary monitoring equipment to prevent the loss of protection when the state of operation is changed, such as the voltage-type electric shock protector, neutral -wire grounding device should be installed.
1neutral . How to prevent electric liveaccident?
What happens after a fire? First of all, in the installation of electrical equipment, must ensure the quality, and should meet the requirements of livesafety. To use qualified electrical equipment, broken switches, lamp caps and broken wires can not be used, wiring joints should be connected to the provisions of the reliable connection, and the insulation tape wrapped. The wiring of the connecting pile head and terminal should tighten the screws to prevent the contact defect caused by the wiring loosening.
Electrician installed equipment, does not mean that can be once and for all, the user in the process, such as the discovery of lamp caps, socket wiring loosening (especially mobile electrical plugs easy to loose), poor contact or overheating phenomenon, to find an electrician in time to deal with.
Second, do not in low-voltage wires and switches, sockets, fuses near the place oil, cotton, sawdust, wood and other easily dyed items. Before the electrical fire, there is a precursor to particular attention, that is, the electric wire overheating will first scorch the insulating skin, emitting a burning rubber, burning plastic unpleasant smell.
Therefore, when the smell of this smell, should first think that may be caused by electrical reasons, such as no other reason, should immediately pull out the power cut, until the cause of the investigation, properly handled, can be put on the electricity. In case of a fire, whether or not it is caused by electrical, first of all to find ways to quickly cut off the livewithin the range of power. Because, if the liveis caused by electrical, cut off the power, also cut off the ignition of the fire; if the liveis not caused by electrical, will also burn out the insulation of the wire, if not cut off the power, the burnt wire will cause a short circuit, causing a wider range of wire fire. In case of electrical fire, cover soil, sand, or liveextinguisher should be used, but no foam extinguisher can be used, so the extinguishing agent is conductive.
11. General knowledge of engineering safety
(1), each construction unit must have some necessary electrical appliances, such as inspection electroprobe, screwdriver, glue pliers, etc., must also have a suitable for the use of the use of screen electrical appliances with various specifications of the fuse and fuse.
(2), each LED signs user must be equipped with total insurance, total breaker and leakage protection switch.
(3), in any case prohibited area with copper, wire instead of fuses. The size of the fuse must match the capacitance of the electricity.Replace the fuse to remove the porcelain lid replacement, not directly in the porcelain box lap fuse, not in the case of electricity to replace the fuse.
(4), after the fuse or leakage switch action, must find out the reason to close the switching power supply.Under no circumstances shall be used to wire the insurance short or press the leakage switch tripping mechanism to forcibly power the transmission.
(5), the purchase of screen electrical appliances should carefully check the technical parameters of the product specification (such as frequency, voltage, etc.) to meet local electricity requirements.To understand how much power consumption, the user has the power to meet the requirements, in particular, wiring capacity, plugs, sockets, fuses, electric meters to meet the requirements.
(6), when the screen power distribution equipment can not meet the overall use of outdoor LED signs
electrical capacity requirements, should be replaced by the transformation, strictly prohibited use.Otherwise overload operation will damage electrical equipment, but also may cause electrical fire.
(7), buy screen electrical appliances should also understand its insulation performance: is general insulation, strengthen insulation or double insulation. If it is grounded for leakage protection, the grounding wire is essential.Even the electrical equipment that strengthens the insulation or the double insulation, protects the ground or protects to receive neutral also to have the benefit.
(8), with motor type of screen electrical appliances (such as exhaust fan, air-conditioning, etc.), should also understand the heat-resistant level, whether the continuous operation for a long time.Pay attention to the heat dissipation conditions of the electrical apparatus.
(9), the installation of screen electrical appliances should be viewed before the installation of the requirements of the environment, special attention to the possible conditions, do not install the screen with hot and humid, dusty or flammable, explosive, corrosive gas environment.
(10 ), in the laying of the screen inside the wiring, phase wires, neutral wires should be clear signs, and the screen with the electrical equipment wiring to maintain the same, do not connect to each other wrong.
(11), the screen electrical appliances and power connections, you must use a switch or plug connector can be opened, prohibit the direct insertion of the wire into the socket hole.
(12), where the requirements of protection grounding or security access to zero screen appliances, should be used three-pin Plug and three-eye sockets, not to use the two-pin Plug and binocular socket substitution, resulting in grounding (or neutral ) wire space.
(13), LED signs wiring between the best without connectors. Must be in contact with a solid and insulated tape winding, or a porcelain junction box.Use medical adhesive tape instead of electrical tape to bind the joint.
(14), wire and switch, breaker gate, insurance box, lamp, such as the connection should be solid and reliable, good contact.Multi-adhesive soft copper wire joints should be twisted together and then placed under the joint screw gasket, to prevent the fine strands of the wire spread to touch another connector caused by short circuit.
(15), LED signs engineering wiring shall not be directly laid on the flammable building materials, such as the need to wiring in the wood must use porcelain beads or porcelain clips;
Flammable plastics and other flammable materials shall not be used as decoration material.
(16), grounding or neutral wires, although normal when not charged, but if the disconnection after the leakage will make the power of electrical shell charged;For its safety, grounding (neutral ) wire specifications should not be less than the phase conductor, on its not to install a switch or fuse, also must not have joints.
(17), grounding wire shall not be connected to the pipe (because now the plug of the hose is used is insulated belt, no grounding effect); shall not be connected to the gas tube (in case of electric spark causing gas explosion); shall not be connected to the ground wire of the telephone wire and shall not be connected to the lightning (in case of lightning strike).
(18), all switches, breaker gates, insurance boxes must have a lid. Bakelite cover plate Aging, incomplete must be replaced.Dirty damp people must be wiped clean before use.
(19), the power cord do not drag and drop on the ground, to prevent the power wire tripping people, and to prevent damage to insulation.
(20), screen electrical appliances before trial should be compared to the manual, all switches, buttons are placed in the original stop position, and then according to the instructions required by the operation sequence.If you have moving parts, you should consider enough space in advance.
(21), LED signs after the discovery of angry flowers, smoke or burning smell, such as abnormal conditions, should be immediately shut down and cut off power, for inspection.
(22), Mobile LED signs electrical appliances must cut off the power to prevent electric shock.
(23), heating electrical appliances must be away from flammable materials around.Heating appliances (such as power supply) should not be placed directly on board, lest cause fire.
(24), prohibit the use of wet hands to contact with the electric switch, the use of wet hands to unplug, plug the Power plug, unplug, plug the finger should not contact the metal part of the contact, and can not use wet hands to replace electrical components or light bulbs.
(25), for the use of electrical appliances often hand (such as hair dryer, electric iron, etc.), should not be twisted in the hands of the wire to use.
(26), for contact with the human body of electrical appliances, such as electric soldering iron, should be tested before the use of electricity, there is no leakage before contact with the human body.
(27), prohibit the use of towed wire method to move the power supply;
(28), the use of screen electrical appliances, first plug in the electric side of the socket, and finally close the breaker or plug in the electric side of the socket, stop the screen with electrical appliances, in contrast, the first to open the live side of the switch or unplug the electric side socket, and then pull out the electric side of the socket (if need to unplug the words)
(29), emergency needs to cut off the power wire, must be insulated electrician pliers or with insulated handle tool.
(30), the rescue of electric shock personnel, the first to disconnect the power supply or board, insulated rod to pick out the power cord, do not use hands to drag the electric shock personnel directly, lest the serial electric shock.
(31), screen electrical appliances, in addition to air-conditioning such electrical appliances, must be turned off power, especially electric electrical appliances, to prevent a long period of fever caused by fire.
(32), screen electrical appliances burnt, smoke, fire, must immediately disconnect the power, should not use water or foam liveextinguisher pouring.
(33), the screen wiring and electrical equipment to the regular insulation inspection, found that the damage to be timely with electrical tape wrapped around.
(34), in the rainy season or long time not to reuse the LED signs, 500 V shaking table measurement of its insulation resistance should be no less than 1mω, can be considered good insulation, can be used normally.If there is no shaking table, at least the application of electroprobe inspection is often checked for leakage phenomenon.
(35), on the often used led signs on the electrical equipment, should keep its dry and clean, do not use petrol, alcohol, soap, water, cleansers, etc. with corrosive or conductive liquid wipe the electrical surface.
(36), LED display screen
with electrical damage to the professional to be repaired; non-professionals are forbidden to open led signs with electrical case.