【 Weak current College 】 residential electrical circuit design principles of fire safety-Power By 【 China power house network 】

With the development of the society, people living standards and requirements, since the late 1990s, China's urban and rural residential from practical to moderate-income, practical home each household construction area for 60 ~ 80 square meters, each household electrical load of 4 ~ 6kW; well-to-do residential building area per household to lOO ㎡, each household electrical load of 6 ~ 8kW. China's urban and rural housing is large, tall, versatile, comprehensive, multi-purpose of direction, at the same time, since many of these houses with electrical appliances, modern plastic material, wiring-intensive features, once the fire consequences unimaginable.
At present, the apartments in the fire and electrical design is also very backward, in the event of fire, the loss is huge. Users of electricity requirements objectively to the well-to-do residential electrical design set higher standards. Residential electrical design level, reflecting a modern city and the people's living standards. Therefore, the requirements for electrical design should take into account the reasonable arrangement of household appliances, the overall effect; the living environment of comfort and security and the humanist design idea of fire safety.
1 residential power distribution system
Residential electricity standard is achieved through the distribution system. The system is able to provide enough power to end the unreasonable design of the system can also affect household use.
This is the design House of minimum standards, specific projects are often under each household size, user requirements and design standards, and other appropriate additional outlet circuit. We need to use the tenants require specific analysis. In General, the lighting branch is able to meet, often appear in a outlet branch-branch and air conditioning. Only over the household appliances, lOOW outlet branch on a TV, stereo, refrigerator, electric oven, microwave oven, rice cooker, washing machine, electric water heaters, electric iron, hair dryer and computers, and other electrical equipment. If you have more of these appliances, may simultaneously use multiple devices may occur overload trip. Air conditioning branch are two split or window type air conditioner is usually no problem, but the increase in the number and then air conditioners or including bulk air conditioning (such as the cupboard) also occur overload trip to power down. Therefore, in practical projects tend to increase, as in a outlet circuit is greater than 30 sqm living room set conditioner outlet, a single set of residential area larger increase outlet circuit, kitchen and separate outlet branch for the bathroom heater set dedicated socket, etc. It is important to note that distribution circuit for occasional overload trip (as in input big load) is not a serious problem, whether you want to check out overloaded overload when the circuit breaker tripping is circuit protection of normal reaction, if by staggering the equipment uses electricity time resolved, is acceptable.
If the end of the distribution system does not meet the requirements, under certain conditions, to resolve through the transformation. Would be to increase the distribution box outlet circuit or intensify outlet circuit breaker setting value and increase the wire section. When the meter case focused on the public area, distribution box located at the indoor time transformation of simple to implement; when households all branches are located in the public area of the distribution box attracted, reconstruction will be very difficult. Because the meter case is determined by the electricity sector and real estate management company to manage, to Filch and management needs, general household changes is strictly prohibited. Construction conditions are very important, the indoor distribution box located on the concrete wall or brick walls, whether conditions plus packing and distribution of the original dark line distribution dark tube conductor can extract (swap lines) that need only be determined after a site survey. In addition, residential property, property management Department of licensing is also indispensable.
2 household electrical design principles
Household electrical design is the design of the decoration (here is the furniture, electrical equipment layout and design of the roof) completes. Because each family decoration design configuration setups, household electrical appliances are also different, this article only on some electrical design principles.
2.1 lighting, outlet circuit must be set separately
The lighting and outlet circuit separation benefit is if the outlet circuit of the electrical equipment fails, only the circuit of a power failure, will not affect the lighting circuit, thereby facilitating fault circuit for maintenance; on the other hand, if the lighting circuit fault occurs, at which point you can use Socket loop power, connected to the lamp for maintenance.
2.2 lighting line should be divided into several loop
This is because once a loop of lights appear short circuit fault, nor will it affect other circuits for lighting, so that the whole family is in the dark.
2.3 on air conditioning, electric water heaters, etc. larger capacity electrical equipment should be a device sets a loop
If the above equipment combined with a loop, when they are used simultaneously, fever, even if the conductor easy does not exceed the allowable working temperature of the conductor, will also reduce the life of the wire insulation. In addition, wire cross section can greatly reduce power loss on the wire.
2.4 bathrooms are especially important for electrical design
The bathroom can be classified into two categories: dry and wet separate bathrooms and wet together in the bathroom. Wet toilet/shower and a toilet; dry sanitation asked placed washbasin and washing machine. Place the bath bathroom is humid environment, with a wet hand operating power switch involve a certain degree of risk, so the power switch mounted on the wet toilet outside of the door wall.
If installed in the bathroom should be used in line switch or waterproof switch.
Heating in bathrooms, equipped with private shower outlet. Front lamp down must also set the electric shaver, hair dryer and bake, and other outlets. Bathroom heater power cable directly from household distribution box with 3 root 2.5m sqm of copper wire lead. Bathroom heater with one switch control general lighting, with one or two switches to control infrared lamp. Bathroom distribution circuit should have residual current protection, lamps and metal casing should be grounded.
2.5 grounding measures
(1) is not intended for use with tap water pipe as the grounding line. New residential buildings are configured for reliable grounding wire, and the old houses are often no grounding line, many of the old residence of the user to tap water pipe as the grounding line. This is not only easy to make the electrical lines cause a fire hazard and can cause people to touch a liveTap was killed by electric shock;
(2) in order to ensure safe, bathroom should adopt the equipotential bonding. The bathroom all metal objects (including metal Towel rack, cast iron bath, water pipes, etc.) and integration with Earth wire, and reliable grounding. Socket and bathroom lighting circuit protection measures must be adopted-grounding. Bathroom outlets in addition to the use of isolating transformer power supply (e.g., electric shaver outlet) can not grounded, other socket it must be enclosed in three-pole socket, Bathroom lighting, metal shell must be grounded. Because the bathroom belongs to the humid environment, easy to throw an electrical circuit failure, increased fire risk. At the same time, the human touch 50V voltage safety below, given electric shocks.
(3) electrical design, you must first know where it comes from the user the power and the power of the grounding. Ground fault protection measures should be consistent with the power supply system;
(4) each loop should set up a separate Earth wire. Some people think that grounded in current is small, several loop combined with a grounding cost savings and decoration. This view is wrong. Because in the normal working hours, grounded in current is very small, but in the event of a short circuit fault, grounding line of current in the flow will greatly exceed the line current when normal work; in addition, from a reliability perspective, a loop of a grounding line more reliable;
(5) even if install leakage protection facilities, should also have the ground protection. Any kind of electrical products, there is the possibility of failure, leakage switch also has the possibility of failure. There is a ground fault protection, when leakage switch failure, ground fault protection is still able to play a protective role. But the output leakage switches cannot be neutral and ground contact, the switch will not be able to close;
(6) has a good grounding system, each household is still configured leakage switch. When an electrical device shell live, grounding resistance then small, at fault is not discharged, the device shell on ground potential also exists and has a fire hazard. If a leakage switch, as long as the leakage current is greater than 30mA, in 0.1s time makes the power disconnect. Human contact socket at any time by following the possible electrical equipment, the socket must have a leakage protection. Wall air conditioning due to difficult to meet without leakage protection.
2.6 electricity capacity corresponds to and design ability
Each household electrical capacity and design skills, don't blindly loaded then high-power electrical equipment. To this end, each household residents in electrical decoration, make a preliminary estimate of the total capacity of indoor load to avoid exceeding the design load of work. Specific figures which can be obtained from local property management consulting.
2.7 select belt protection board socket
Electrical safety design is key, each family member in daily contact with household electrical equipment, home both silly boy, also have some knowledge in electrical knowledge, not understand electrical safety knowledge of adults, in order to ensure the safety of power, must pay attention to the design of electrical safety. Children can touch the socket, you should choose the belt Protection Board of the socket to avoid children put metal objects into the socket with electric shock and fire within the trigger.
Do not use the "three 2.8 without" products
As a result of the use of poor quality electric heater shower and shock occurs, the death of the accident was reported at the time of the media. Therefore, do not use the family decoration "three free" products, especially Jack, "three" product market, it should be noted that identification. Don't be blind pursuit of mooring to products, proposed purchase of brand-name products made in China.
3 wire protection tube
The wires are not allowed to directly laying in the wall, you must wire protection tube to protect it. Very unfortunately the residential design code (GB50096-1999) is not on the type of wire protective tube. And the electrical equipment installation engineering lkV and following wiring construction and acceptance (GB50258-1996) have the following requirements: humid places and direct buried cable protection hose, thick-walled steel pipe or should be used to prevent liquid-flexible metal wire protection tube; dry places of wire protection tube used thin-walled steel or flexible metal wire protection tube; plastic pipe should not be laid at high temperatures and vulnerable to mechanical damage, protect the wires of plastic pipe and fittings must be flame and factory standard; metal hose should be laying in vulnerable to mechanical damage in dry place, and should not be buried in the underground or concrete. The residential building design standards (DBJ08-20-1998): power supply, telephone, TV circuit should be concealed retardant pipes.
Flame retardant pipes due to cheaper prices than the metal pipe, construction convenient, does not rust, etc., in the family decoration by users.
Home decoration, wire protection tube should effectively check:
(1) check whether there is a plastic pipe production plant tags and flame-resistant tag, both of these tags protection pipe can not be used;
(2) the use of fire makes plastic pipe, pipe evacuation fire burning in the 30s in self-extinguishing; for flame test
(3) bent pipe should be worn when someone special spring. Test, the pipe bend 90 °, the bending radius is 3 times the diameter should be smooth curved appearance; after
(4) with his hammer percussion to protect pipe deformation, no crack for impact test.
Home decoration in addition to the use of flame retardant pipes concealed protective wire, metal wire protection available. If any of the residential building power cord with flame retardant plastic pipe protection, telephone, cable TV with galvanized metal thin-walled pipes (shielding effect to play). Telephone and cable television transmission line of metal protection hose does not have to set up cross-wiring, this is because the silk mouth connection or socket connection of galvanized pipe has been able to reach the shielding requirements.
Pipe should not be folded flat and cracks appear, the tube should be no burrs, steel pipe outside diameter and wall thickness should be consistent with the relevant national standards, if steel stranded wire when rotten teeth or steel brittle fracture phenomena, that pipe quality does not meet the requirements.
Suspended ceiling in the junction box to the lighting of the conductor hose hose with plastic hose, metal hoses, plastic-metal hoses and pulika hose. Home decoration in general plastic hose or plastic-metal hoses, not plastic-metal hoses, hose to the grounding. Pulika pipe with metal strength, but also has the hose can be flexible,This was the high residential use.