How to choose a wire in their section and power
Sizing cables is an important step in the design of power supply a house or apartment. With insufficient wire section is overheated, which can lead to melting of the insulation and short-circuit, the consequences of which are unpredictable.
Conductor cross-sections are selected for the value flowing through them and the current can be determined from tables or calculated. Table section of the conductor wiring requirements are specified in the "Rules for Electrical Installation" (PUE). In the same normative document contains a table with the maximum permissible currents depending on the conductor cross-section and operating conditions. Below is a table of cases, most often encountered when installing wiring in houses and apartments.
Keep in mind that, according to the SAE-section of copper wires for homes must be at least 2.5 square meters. mm and 1.5 square meters. mm after them. Before wiring to examine the situation of the SAE on houses. Compliance with these requirements will allow them to improve the reliability of power supply and avoid claims of Energonadzor.
Rated load current wires As the table shows, the nominal load current of wires depends on the cooling of the conductors. Wire, laid in the walls, channels and pipes are not blown by air, so cool slowly. Thick wire transfer heat worse than thin and kept smaller current density. The current density is determined by dividing the allowable current to the wire size. For aluminum wires it is within 5 - 10 A / sq. mm, for copper - 7 - 15 A / sq. mm. Multiplying the current density of the load current can determine the required wire size.
Use for wiring the flat copper conductors - they are less oxidized and do not break at the joints, so are more reliable.
The use of aluminum in hazardous occupations prohibited without reason. Calculation of cable cross-section of the power consumers of electricity Calculation of wire sizes to start with the definition of the total power load on the electrical network. It is especially important to take into account the major power consumers, having the following characteristics: iron - 1 - 2 kW; washing machine - up to 2 kW; vacuum cleaner - 1 - 2 kW; water heater - about 2 kW; electric - 1 - 2 kW; Microwave - 0.6 - 2 kW; electric - up to 2 kW; Air conditioning - up to 3 kW; fridge - about 1 kW; electric heating boiler - 2 - 5 kW; lighting - power one light bulb, multiplied by the number of them. Power electrical appliances can be specified in the instruction manual. Calculate the total power of the consumers, and dividing its value by 220 volts, define the load current.
Further tables or find current density wire size.
When calculating the power you need to keep in mind that not all consumers are included at the same time - if the boiler is heating, air conditioning, no one uses it. This fact can be taken into account by multiplying by a factor of the total power demand. Empirically it found that for flats with a total power of 14 kW it is 0.8 to 20 kW - 0.65 kW to 50 kW - 0.5. For example, consider the selection of cable cross-section from the junction box to the kitchen outlets. The kitchen includes a refrigerator 1 kW, dishwasher - 1 kW electric - 2 kW microwave - 0.8 kW electric oven - 2 kW and air conditioning - 2 kW.
The total capacity is 8.8 kW. Multiply this value by a factor of 0.8 in demand and obtain 7.04 kW. Translate kilowatts in watts (1 kW = 1000 W) and determines the load current: I = 7040/220 = 32 A. As the table flush select twisted pair copper wire cross section Q3. mm or aluminum - 5 sq. mm. The same section we obtain by dividing current to the average values of its density. Sometimes available unknown wire section. Knowing a diameter section readily determined by the formula S = 0,785D2, where D - diameter of the conductor. For stranded wires result is multiplied by 0.785.
How to properly prepare the wall to shtroblenie under wiring and what options exist shtrobleniya, tell our article, previously placed in the group.
Sizing cables is an important step in the design of power supply a house or apartment. With insufficient wire section is overheated, which can lead to melting of the insulation and short-circuit, the consequences of which are unpredictable.
Conductor cross-sections are selected for the value flowing through them and the current can be determined from tables or calculated. Table section of the conductor wiring requirements are specified in the "Rules for Electrical Installation" (PUE). In the same normative document contains a table with the maximum permissible currents depending on the conductor cross-section and operating conditions. Below is a table of cases, most often encountered when installing wiring in houses and apartments.
Keep in mind that, according to the SAE-section of copper wires for homes must be at least 2.5 square meters. mm and 1.5 square meters. mm after them. Before wiring to examine the situation of the SAE on houses. Compliance with these requirements will allow them to improve the reliability of power supply and avoid claims of Energonadzor.
Rated load current wires As the table shows, the nominal load current of wires depends on the cooling of the conductors. Wire, laid in the walls, channels and pipes are not blown by air, so cool slowly. Thick wire transfer heat worse than thin and kept smaller current density. The current density is determined by dividing the allowable current to the wire size. For aluminum wires it is within 5 - 10 A / sq. mm, for copper - 7 - 15 A / sq. mm. Multiplying the current density of the load current can determine the required wire size.
Use for wiring the flat copper conductors - they are less oxidized and do not break at the joints, so are more reliable.
The use of aluminum in hazardous occupations prohibited without reason. Calculation of cable cross-section of the power consumers of electricity Calculation of wire sizes to start with the definition of the total power load on the electrical network. It is especially important to take into account the major power consumers, having the following characteristics: iron - 1 - 2 kW; washing machine - up to 2 kW; vacuum cleaner - 1 - 2 kW; water heater - about 2 kW; electric - 1 - 2 kW; Microwave - 0.6 - 2 kW; electric - up to 2 kW; Air conditioning - up to 3 kW; fridge - about 1 kW; electric heating boiler - 2 - 5 kW; lighting - power one light bulb, multiplied by the number of them. Power electrical appliances can be specified in the instruction manual. Calculate the total power of the consumers, and dividing its value by 220 volts, define the load current.
Further tables or find current density wire size.
When calculating the power you need to keep in mind that not all consumers are included at the same time - if the boiler is heating, air conditioning, no one uses it. This fact can be taken into account by multiplying by a factor of the total power demand. Empirically it found that for flats with a total power of 14 kW it is 0.8 to 20 kW - 0.65 kW to 50 kW - 0.5. For example, consider the selection of cable cross-section from the junction box to the kitchen outlets. The kitchen includes a refrigerator 1 kW, dishwasher - 1 kW electric - 2 kW microwave - 0.8 kW electric oven - 2 kW and air conditioning - 2 kW.
The total capacity is 8.8 kW. Multiply this value by a factor of 0.8 in demand and obtain 7.04 kW. Translate kilowatts in watts (1 kW = 1000 W) and determines the load current: I = 7040/220 = 32 A. As the table flush select twisted pair copper wire cross section Q3. mm or aluminum - 5 sq. mm. The same section we obtain by dividing current to the average values of its density. Sometimes available unknown wire section. Knowing a diameter section readily determined by the formula S = 0,785D2, where D - diameter of the conductor. For stranded wires result is multiplied by 0.785.
How to properly prepare the wall to shtroblenie under wiring and what options exist shtrobleniya, tell our article, previously placed in the group.
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