A few square meters of wire is a nominal value stipulated by the national standard. It is the user who selects the wire and cable according to the load of the wire and cable. How does the wire look at the square? How is the square of the wire calculated? Following Xiaobian understand it.
The square of the wire is actually marked by the cross-sectional area of ​​the wire, that is, the area of ​​the round cross-section of the wire in square millimeters.
If you want to determine the thickness of the wire (square), use a vernier to measure the diameter of the wire, and then calculate the cross-section, section of the calculation formula: S = radius squared R?? × π. For example, a line with a diameter of 1.76 is 1.76 x 2 x 3.14 = 2.76 x 2.5 squared (approximate). If you want to select the size of the wire, it is generally based on the size of the power used to calculate the current, and then according to the current in the inspection of electrical manual, this is more accurate.
If it is single-core, its diameter can be measured, and then the radius can be obtained. According to the area formula, S = radius * radius * 3.14, the cross-sectional area of ​​the wire can be known, and some lines are twisted by multiple core combinations. Together, so you can not use the single-core method to calculate, can only be based on this line in one of the lines to take a single core count, and then multiply the number of lines can be, the formula is S = radius * radius * 3.14*N, where N is the number of twisted wires!
Calculate the square of the wire. Wire and cable size is specified in squares. Multi-strand wire is the sum of the cross-sectional area of ​​each wire, for example 48 strands (0.2 strands per strand) 1.5 square strands: 0.785X (0.2X0.2)X48= 1.5
Calculation of conductor cross-sectional area and current-carrying capacity A. The safe current-carrying capacity of general copper-carrying current-carrying conductors is determined based on the maximum allowable core temperature, cooling conditions, and laying conditions. The safe current-carrying capacity of copper wires is generally 5~8A/mm2, and the safe current-carrying capacity of aluminum wires is 3~5A/mm2. [Key points] The safe current carrying capacity of copper wire is 5~8A/mm2, and the safe current carrying capacity of aluminum wire is 3~5A/mm2. Such as: 2.5mm2BVV copper wire safe carrying capacity recommended value of 2.5 × 8A/mm2 = 20A4mm2BVV copper conductor safe carrying capacity recommended value 4 × 8A/mm2 = 32A.
2. Calculate the cross-sectional area of ​​copper conductors Use the recommended value of safe current-carrying capacity of copper conductors 5~8A/mm2. Calculate the upper and lower ranges of the cross-sectional area S of the selected copper conductors: S=[I/(5~8)]=0.125I~ 0.2I (mm2) S----- copper conductor cross-sectional area (mm2) I----- load current (A).
Third, the power to calculate the general load (can also be used electrical appliances, such as lighting, refrigerators, etc.) is divided into two types, one type of resistive load, one is inductive load. The calculation formula for the resistive load: P=UI The calculation formula for the fluorescent lamp load: P=UIcosф, where the power factor of the fluorescent lamp load is cosф=0.5. Different inductive loads have different power factors, and the power factor cos can be taken as 0.8 when the household appliances are uniformly calculated. In other words, if a household has all appliances plus a total power of 6000 watts, the maximum current is I=P/Ucosф=6000/220*0.8=34(A) However, under normal circumstances, it is not possible to use household appliances at the same time. Therefore, plus a common coefficient, the common coefficient is generally 0.5. Therefore, the above calculation should be rewritten as I=P*common coefficient/Ucosф=6000*0.5/220*0.8=17(A) That is, the total current value of this home is 17A. The total gate air switch can not use 16A, should use more than 17A.
About the wire, how to look at the square and the square of the wire, the relevant information is introduced here for everyone, and we hope to help everyone.
The square of the wire is actually marked by the cross-sectional area of ​​the wire, that is, the area of ​​the round cross-section of the wire in square millimeters.
If you want to determine the thickness of the wire (square), use a vernier to measure the diameter of the wire, and then calculate the cross-section, section of the calculation formula: S = radius squared R?? × π. For example, a line with a diameter of 1.76 is 1.76 x 2 x 3.14 = 2.76 x 2.5 squared (approximate). If you want to select the size of the wire, it is generally based on the size of the power used to calculate the current, and then according to the current in the inspection of electrical manual, this is more accurate.
If it is single-core, its diameter can be measured, and then the radius can be obtained. According to the area formula, S = radius * radius * 3.14, the cross-sectional area of ​​the wire can be known, and some lines are twisted by multiple core combinations. Together, so you can not use the single-core method to calculate, can only be based on this line in one of the lines to take a single core count, and then multiply the number of lines can be, the formula is S = radius * radius * 3.14*N, where N is the number of twisted wires!
Calculate the square of the wire. Wire and cable size is specified in squares. Multi-strand wire is the sum of the cross-sectional area of ​​each wire, for example 48 strands (0.2 strands per strand) 1.5 square strands: 0.785X (0.2X0.2)X48= 1.5
Calculation of conductor cross-sectional area and current-carrying capacity A. The safe current-carrying capacity of general copper-carrying current-carrying conductors is determined based on the maximum allowable core temperature, cooling conditions, and laying conditions. The safe current-carrying capacity of copper wires is generally 5~8A/mm2, and the safe current-carrying capacity of aluminum wires is 3~5A/mm2. [Key points] The safe current carrying capacity of copper wire is 5~8A/mm2, and the safe current carrying capacity of aluminum wire is 3~5A/mm2. Such as: 2.5mm2BVV copper wire safe carrying capacity recommended value of 2.5 × 8A/mm2 = 20A4mm2BVV copper conductor safe carrying capacity recommended value 4 × 8A/mm2 = 32A.
2. Calculate the cross-sectional area of ​​copper conductors Use the recommended value of safe current-carrying capacity of copper conductors 5~8A/mm2. Calculate the upper and lower ranges of the cross-sectional area S of the selected copper conductors: S=[I/(5~8)]=0.125I~ 0.2I (mm2) S----- copper conductor cross-sectional area (mm2) I----- load current (A).
Third, the power to calculate the general load (can also be used electrical appliances, such as lighting, refrigerators, etc.) is divided into two types, one type of resistive load, one is inductive load. The calculation formula for the resistive load: P=UI The calculation formula for the fluorescent lamp load: P=UIcosф, where the power factor of the fluorescent lamp load is cosф=0.5. Different inductive loads have different power factors, and the power factor cos can be taken as 0.8 when the household appliances are uniformly calculated. In other words, if a household has all appliances plus a total power of 6000 watts, the maximum current is I=P/Ucosф=6000/220*0.8=34(A) However, under normal circumstances, it is not possible to use household appliances at the same time. Therefore, plus a common coefficient, the common coefficient is generally 0.5. Therefore, the above calculation should be rewritten as I=P*common coefficient/Ucosф=6000*0.5/220*0.8=17(A) That is, the total current value of this home is 17A. The total gate air switch can not use 16A, should use more than 17A.
About the wire, how to look at the square and the square of the wire, the relevant information is introduced here for everyone, and we hope to help everyone.
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