With the advent of technological development and the era of intelligent architecture, weak and strong electricity projects are getting more and more attention, but how many people know their difference;
Weak currents: Weak currents are very common. Weak currents exist in almost all electronic products. Weak currents refer to the currents and voltages required to transmit signals compared to strong currents. Weak currents are characterized by low current, high frequency, and low voltage. For example, the voltage coming out of the MCU pin is very small, which is used for signal processing. This is weak current.
Strong electricity: strong electricity is generally electricity in the power system, for example 220v of lighting electricity, and more than 1000 v of industrial electricity, etc. Strong electricity is characterized by high voltage, low frequency, large current, strong electricity is used to drive High power electrical equipment. Such as electric motors, electric lights and other electrical equipment.
The home circuit is divided into strong and weak electricity. In the power system, the voltage below 36V is called safety voltage, the voltage below 1kv is called low voltage, and the voltage above 1kv is called high voltage, and the line directly supplying power to users is called distribution line. For example, if the user's voltage is 380/220v, it is called a low-voltage distribution line, which is the strong electricity in home decoration (because it is the highest voltage for home use). Strong electric generally refers to alternating voltages above 24V. Such as home lights, sockets, etc., voltage 110V ~ 220V. Home electrical lighting, electric water heaters, heaters, refrigerators, televisions, air conditioners, audio equipment and other electrical appliances are strong electrical equipment. The intelligent system is a comprehensive system composed of a monitoring system for building equipment, a security system, a communication network system, an information network system, an automatic fire alarm system, and a fire fighting linkage system. The system is composed of centralized monitoring, control, and management. The lines of control, network systems, etc., control, management, and communication are called intelligent lines (that is, weak electricity in home improvement). Weak electricity generally refers to DC circuits or audio, video lines, network lines, telephone lines, DC voltage is generally within 24V. Household electrical appliances such as telephones, computers, and televisions, which use signal input (cable television lines) and audio equipment (output lines), are low-voltage electrical devices.
Strong and weak electricity
Electronic people are used to being divided into two parts: strong electricity (electricity) and weak electricity (information). The two are both related and different. In general, the object of processing a strong current is energy (electricity). Its characteristics are high voltage, large current, large power, and low frequency. The main considerations are reducing losses, improving efficiency, and weak currents. The main object of the processing is information, namely the transmission and control of information. Its characteristics are low voltage, low current, low power and high frequency. The main consideration is the effect of information transmission, such as the fidelity, speed, and breadth of information transmission. ,reliability. In general, weak current projects include television engineering, communications engineering, fire engineering, security engineering, imaging engineering, etc., and integrated wiring works for the above-mentioned projects. Weak electricity is for strong electricity. Strong electricity = (380/220), no matter high pressure. Strong and weak currents are generally easy to distinguish conceptually. The main difference is the difference in use. Strong electricity is used as a power source and weak electricity is used for information transmission.
Specifically, they roughly have the following differences: (1) Different AC frequencies: The frequency of strong electricity is generally 50Hz (Hz), which is called "power frequency", which means the frequency of industrial electricity: the frequency of weak electricity is often high frequency or Very high frequencies, measured in KHz (kilohertz) and MHz (megahertz). (2) Different transmission methods: Strong electricity is transmitted on transmission lines, and transmission of weak electricity is divided into wired and wireless. The radio transmits electromagnetic waves. (3) Power, voltage, and current sizes are different Strong electric power is measured in KW (kilowatts), MW (megawatts), voltage is in V (volts), KV (kilovolts), current is A (ampere), kA (kiloampere) ); weak electrical power in W (watts), mW (milliwatts), voltage in V (volts), mV (mV), current in mA (milliampere), uA (microampere), and thus its circuit It can be composed of printed circuits or integrated circuits. Of course, there are also high-frequency (hundreds of KHz) and medium-frequency devices in high-power systems, but the voltage is higher and the current is larger. Another example is that flashlights and electric razors, while having a low voltage and low power and current, are still powerful. Due to the development of modern technology, weak electricity has penetrated into the field of strong electricity, such as power electronic devices, wireless remote control, etc., but these can only be regarded as a weak electric control part in strong electric power, and it is still different from the controlled strong electric power.
In the field of building electrical technology, people are accustomed to dividing it into two parts: strong electricity (electricity) and weak electricity (information). The two are both related and different. In general, the object of processing a strong current is energy (electricity). Its characteristics are high voltage, large current, large power, and low frequency. The main consideration is to reduce losses and improve efficiency. The main object of the processing is information, namely the transmission and control of information. Its characteristics are low voltage, low current, low power and high frequency. The main consideration is the effect of information transmission, such as the fidelity, speed, and breadth of information transmission. ,reliability. In general, weak current projects include television engineering, communications engineering, fire engineering, security engineering, imaging engineering, etc., and integrated wiring works for the above-mentioned projects. Weak electricity is for strong electricity. Strong electricity = (380/220), no matter high pressure.
The wiring of modern buildings does not always have the distinction between strong and weak electric wells. There are only 380/220v cables in metal bridges of strong electric wells, and there are many line patterns in weak electric wells, such as optical fibers, twisted pairs, video lines, control lines, and network cables. Etc., etc., so intuitive and easy to distinguish it, the two are still very particular about the wiring, such as spacing, shielding, grounding, etc., so now there is a measure of internal lightning protection, reasonable wiring is critical, strong and weak electricity The cable can not be laid in the same slot. By simulating the different electromagnetic induction effects of wiring and shielding on the signal line, the wiring of the computer communication network system in the building has the following conclusions: 1. Cables entering the equipment room should be laid on In the metal tank, the layers are connected equipotentially, and the power line and signal line should be laid in parallel and separated by a certain distance to prevent interference.
(Refer to the wiring specification) Second, the layout of communication cables should be concentrated in the middle of the building. Third, the design of communication cable trunking should be located as far as possible from the building upright or beam. Layout should avoid close proximity to the building columns or beams. From the perspective of lightning protection, the wiring must be clearly stated: (1) The power cable should not be set up in the same slot as the network cable, and the data socket must be kept at a certain distance from the power outlet. (2) The WAN cable should not be set up in the same slot as the LAN cable. (3) When the network cable and the wall are arranged, there are conditions that should be installed at a long distance; (4) The thickness of the shielding slot is required, and what steps are required for the two-point grounding electrical installation? Design, construction, material selection, line positioning, chisel wall trench, cloth tube burying box, pipe threading, electrical equipment installation, measurement inspection.
What is the hidden installation of electrical installation? Laid in the brick wall, floor, beam, column, floor, ceiling; dark (found) in the wall or floor, roof junction box, lamp box, switch box, etc. can not see The part is considered a hidden project. What is the later electrical installation project? The latter part of the electrical installation project generally refers to the work of home decoration entering the end after soil, wood, and paint are finished. The contents include: pipe threading, installation of switch boxes inside the switch, wiring; installation of switches, sockets; installation of lamps and lanterns; installation of cable TV branches Device; install visual walkie-talkie and so on. What should be paid attention to when installing electrical hidden works? According to the location of the electrical appliances used in home decoration design, the exact location of the distribution box, switches, sockets, telephone jacks, cable TV jacks, broadband network jacks, audio outlet boxes, lamps, etc. shall be determined and the elevation shall be installed. The connection of the switch, socket box and pipe should be tightly sealed.
The interface between the tube and the tube, the tube and the device is applied with special glue (PVC pipe, junction box). The bending radius of the PVC threading pipe is generally 6 to 10 times the diameter of the pipe. The elbow must be a spring pipe bender specially designed for PVC pipe. The elbow and tees of the finished product should not be used. The bends and tees of the finished product generally cannot meet the bending radius. The pipe is temporarily blocked during construction to ensure threading. The inner wall of the tube is smooth, clean, and dry. What problems should be paid attention to when threading in the pipe? The threading in the pipe shall be performed before the threading is completed, the switch, the socket and the lamp are installed. Pipe mouth, junction box inside the mouth should be added protection ring (lock nut) protection, to prevent damage to the insulation of the wire when threading. Different voltages, different circuits, and wires with different signals must not be put in the same threading tube. Why do the wires have enough clearance in the conduit? It is strictly forbidden to block the inside of the pipe in the threading pipe. The ratio of the cross-sectional area of the general conductor to the cross-sectional area of the conduit is 1:3 to 1:2. The total cross-sectional area of the threading (the outer plastic insulating layer containing the cord) is not larger than 40% of the inner diameter of the tube, ensuring that the threading tube has Adequate gaps allow the wire to dissipate the heat generated by the large current flow in the line tube. Why can't there be joints in the threading pipe? Where should the connector be? It is forbidden to connect the wires in the threading pipe, that is, if the length of the wire is not enough, the joint of the wire cannot be in the threading pipe, and it should be connected in the junction boxes such as switches, sockets, lamp cap boxes, etc. Otherwise, the inside of the pipe may be easily blocked and the heat dissipation may be poor. Points are not easy to find, maintenance is difficult, and may cause electrical fires. When should the later electrical installations be carried out? The later electrical installation works should be completed at the end of the earth, wood, and paint work, and the basic cleaning of the room can be completed. When installing, pay attention to the protection of the finished products of various types of work and prevent the pollution and damage caused by the installation. Why is it forbidden to use mobile bedside lamps? The movable bedside light switch is connected to the switch by a soft insulated wire. If the wire and the switch are separated during use, the exposed live wire ends may cause fire or electric shock. How to determine the capacity of home switch box (distribution box) and the number of loops? The home switch is selected based on the total power of the home appliance.
The total power is 0.8 times the sum of the shunt functions, that is, the total power P total = (P1 + P2 + P3 +... + Pn) × 0.8 (kW) The total switch withstand current should be I total = P total × 4.5 (A) where P total - - total power (capacity) P1, P2, P3, ..., Pn - - shunt power I total - - total current shunt switch withstand current is I = 0.8 Pn × 4.5 (A) and the air-conditioning circuit must consider the starting current, its switching capacity is I air-conditioning = (0.8 Pn × 4.5) × 3 (A) The sub-circuit should be divided according to the family area. In general, the shunt capacity is selected to be less than 1.5kW, and the single-use appliance with a function above 1kW is listed as a sub-circuit (such as air conditioners, electric water heaters, heater lamps and high-power household appliances) How to calculate the power consumption? How to choose the specifications of the wire? Household electricity meters are also called power meters. Calculation of electricity consumption: 1 kWh (kW/h) = 1000W x h The power of the appliance is the product of time. The choice of wire is copper wire. The empirical formula is the wire cross-section (unit: m) ≈ I/4 (A) if the rated current capacity ≈4A of copper wire with 1 m section. Example: The current of a household single-phase watt-hour meter is 40A. Select the wire (1 m, 1.5 m>2.5, 5,6, >10, 16, 25, 35 m<) for the cross-section of the copper conductor. i>
How to choose lamps? When the design has provisions, it should be selected according to the design requirements. When there is no requirement, it can be combined with the preferences of the owner. Kitchens, bathrooms recommend the selection of a glass cover lighting, in order to avoid moisture, smoke pollution light source, easy to clean. The living room can choose some art lamps, the bedroom lamps can choose the ceiling lamp with normal illumination, the illumination should not be too strong. Floor lamp can also be used to obtain warm comfort with wall and ceiling reflections. The lighting of the study room should choose local lighting, such as floor lamp, desk lamp, work lamp. What are the requirements for lighting installation? Luminaire installation should be done after painting. When installing lamps and lanterns on the brick-concrete structure, use pre-embedded hooks, expansion bolts, nylon expansion tubes or plastic expansion tubes, etc. Solid wood is strictly prohibited; when the weight of the lamps is more than 4 kg, the pre-embedded hooks or bolts should be used. . The bearing load capacity of the fixture should match the weight of the fixture. Luminaires shall not be directly installed on combustible components. When the high temperature part of the surface of the luminaire is close to combustibles, heat insulation and heat dissipation measures shall be taken. Pipe hanging lamps, the inner diameter of the steel pipe shall not be less than 10mm; the wall thickness of the steel pipe shall not be less than 1.5mm. The lamp line of the chain hanging lamp shall not be subject to pull, and the lamp line shall be forked together with the hanging chain.
Cords should be protected at both ends of the chandelier, and both ends should be tinned. Lamps installed in a row in the same room or place shall not have a centerline deviation of more than 5mm (except as required by the design). Fluorescent lamps and their accessories should be used together. The installation location should be easy to check and maintain. Lighting fixtures should be secure. When the insulation table is more than 75mm in diameter, the number of bolts for fixing each lamp shall not be less than two. How to choose the socket? What are the rules for installing sockets? At present, home decoration generally choose concealed sockets. There are a wide variety of outlets on the market, but the format is generally the same. It is recommended that owners choose a branded outlet to ensure quality.
(1) The installation height of the socket shall be installed according to the design requirements when the design is specified. When the design is not clear, the following requirements shall generally be met: The socket with the safety door shall not be less than 0.3M. The outlet without security door is not lower than 1.8M. It is recommended to purchase Sockets with Anmun as much as possible, because the prices are not much different.
(2) A well-sealed waterproof and splash-proof socket shall be used in the bathroom or other damp places. Note: The socket with safety door is based on the general socket, and the plastic baffle (safety door) in front of the socket metal reed is added. Three-hole socket, when the plug is inserted, the grounding pile head (slightly long) is inserted into the hole first, and the mechanism action side of the socket opens the other two hole doors. The two hole socket must be inserted into the socket pile head at the same time, and the safety door can be opened to prevent young. The child mistakenly inserted a metal object to cause a safety accident.
(3) When the socket is installed, the panel should be upright and close to the wall. And the wiring (phase) should meet the following requirements: single-phase two-hole socket, facing the right hole of the socket or the upper hole connecting line (FireWire); the left hole or the lower hole is connected to the zero line. The single-phase three-hole socket faces the right-hole connecting line (L, FireWire) of the socket, the left hole connects the neutral line (N), and the upper hole ground line (PE).
How to check the quality of the measuring circuit? The quality of the line is mainly to see if there is no open circuit and the insulation resistance meets the requirements. The measurement method is: cut off the power with a megohmmeter (500V.0 ~ 500M Europe) on the insulation resistance test of each circuit: ~ 220V loop, the insulation resistance should reach 0.25M Europe above is qualified; ~ 380V loop, its insulation resistance Should reach 0.38M Europe or more qualified. What issues should be paid attention to when laying cable television lines? Access to indoor and branch cable distributors for cable television should be based on the number and location of TVs used in homes. Matchers for the corresponding number of branches should be selected and emitted to each point of use. The wires generally use sky75-5 coaxial cable and PVC20 pipes ( The coaxial cable must have a national or local broadcasting and TV license to allow production and access to the network. Note that there must be no connector in the middle of the connection to ensure the viewing effect. Telephone line laying should pay attention to what issues? In addition to the introduction of outdoor telephone lines, in addition to the existing one-line telephone line, it is also necessary to reserve two pairs of input threading pipes PVC16, one pair for communication and the other for computer access broadband network in the future. Some telecommunications departments have set the network cable (broadband) to the outside of each door. Therefore, the network cable 4 (2*0.5) and PVC20 should be set outdoors before the decoration to facilitate connection with the network cable. The quality of the telephone lines and network cables used in the threading tube must comply with the national standards. There must be no joints in the threading tubes, and no water or moisture can be found in the threading tubes. The lines must avoid interference from strong magnetic fields and other high-power electrical appliances. What issues should be paid attention to when installing surround sound speakers for home theater (audio)? In homes with home theaters, the surround sound speakers of their audio equipment are usually placed behind the viewers.
At home, it is therefore necessary to use an 80-100-core RBV2 x 1.5 crystal flat wire to wear the PVC20 tube to the proper position behind the viewer. If other rooms also want to share this video, you can reserve the front line and video line. Electric water heater installation and debugging should pay attention to what? The installation of electric water heaters must use special hooks and expansion tubes or expansion bolts. The installation level must be solid and beautiful. The socket for power supply to the electric water heater must be grounded. Sockets and electric water heater plugs should be matched. During the test, the air in the bladder of the water heater should be excluded. After the water is filled, the electricity can be started.
