Ren Yi's official website was updated on July 8. Wires refer to wires that transmit electrical energy. Divided into bare wire, magnet wire and insulated wire. Bare wires have no insulation layer, including copper, aluminum flat wires, overhead stranded wires, and various profiles (such as molded wires, bus bars, copper bars, aluminum bars, etc.). It is mainly used for outdoor overhead and indoor busbars and switch boxes. Magnet wire is an insulated wire that generates a magnetic field or induces current in a magnetic field after being energized. It is mainly used for winding motors and transformers and other related electromagnetic equipment. The conductor is mainly copper wire, which should have a thin insulating layer and good electrical and mechanical properties, as well as heat resistance, moisture resistance, and solvent resistance. Choose different insulating materials to obtain different characteristics.
Square number of wires
A few squares is a nominal value stipulated by the national standard, and a few squares is the user's choice of wire and cable according to the load of the wire and cable.
The square number of wires is a verbal term in the renovation of hydropower construction. The number of square wires is often said without a unit, that is, square millimeters.
The square of the wire actually refers to the cross-sectional area of the wire, that is, the area of the circular cross-section of the wire, in square millimeters.
Generally speaking, the empirical load capacity is when the grid voltage is 220V, the empirical load capacity per square wire is about one kilowatt.
Each square of copper wire can carry 1-1.5 kilowatts, and each square of aluminum wire can carry 0.6-1 kilowatts. Therefore, only one square of copper wire is sufficient for electrical appliances with a power of 1 kilowatt.
When it comes to current, the copper wire can carry 3A to 5A per square meter during short-distance power transmission. The heat dissipation condition is better to take 5A/square millimeter, and it is not good to take 3A/square millimeter.
Wire square calculation method
Knowing the square of the wire, calculate the radius of the wire with the formula for finding the area of a circle:
Square number of wires (square millimeter) = pi (3.14) × square of wire radius (mm)
Knowing the square of the wire, the same is true for calculating the wire diameter,
For example, the wire diameter of a 2.5 square wire is: 2.5 ÷ 3.14 = 0.8, and the square root is 0.9 mm, so the wire diameter of a 2.5 square wire is: 2×0.9 mm = 1.8 mm.
Knowing the diameter of the wire, the square of the wire is also calculated by the formula for finding the area of a circle:
The square of the wire = the circumference ratio (3.14) × the square of the wire diameter/4
The cable size is also nominally squared, and the multi-stranded wire is the sum of the cross-sectional area of each wire.
Calculation formula of cable cross-sectional area:
0.7854 × the square of the wire radius (mm) × number of strands
For example, 48 strands (each wire with a radius of 0.2 mm) 1.5 square wire: 0.7854 × (0.2 × 0.2) × 48 = 1.5 square
Cable treasure summary version
The square of the wire can be calculated by measuring the diameter of the wire, because the diameter of the wire is better measured,
The formula is S=3.14d/4; d is the diameter.
There is an estimation formula for the load capacity, posted for your reference:
Ten under five; one hundred on two; two five three five four three realms;
Seventy-nine-five times and a half; eighty to ten percent off the temperature of the tube;
Copper wire upgrade calculation; bare wire plus half
Ten under five is ten times under ten times five;
One hundred over two is one hundred over two;
Two, five, three, five, four, three realms are two five times four, and three five times three;
Seven zero nine five and two and a half times means that the seven zero and nine five lines are both multiplied by two and five;
The eight to nine percent off the temperature of the pipe is to change with the change of temperature, multiply the calculated safe current number by 0.8 or 0.9;
The copper wire upgrade is calculated as an increase of one level on the basis of the aluminum core wire of the same cross-section.For example, the 2.5 copper core wire is increased by one level on the 2.5 aluminum core wire, and it is calculated as the four square millimeter aluminum core wire.
Adding half of the bare wire means adding another half to the calculated safe current number.
Simple and flexible
Calculate with this electrician formula: ten under five, one hundred over two, two, five, three, five, four and three circles, seventy-nine-five times and a half, the temperature of the pipe is 80% off, and the copper wire is upgraded.
For example: the number of squares of wires: 1, 1.5, 2.5, 4, 6, 10, 16, 25, 35, 50, 70, 95, 120, 150, 185...
"Ten under five" refers to five times the current value below 10 square
"Hundreds of two" means that a line of more than 100 square meters can flow twice the current value
"Two Five Three Five Four Three Realms"
It means that a wire of 25 square or less and 10 square or more can flow four times the current, and a wire of 35 square or more and 50 square or less can flow three times the current.
"Seven zero nine five two and a half times"
Refers to the 70 square, 95 square wire can flow 2.5 times the current.
The above formula is based on aluminum wire
"Copper wire upgrade calculation"
It means that, for example, I chose a 4 square aluminum wire, and the current flowing through it should be 20A. If you replace it with a copper wire, you can use a 2.5 square wire instead.
Simple algorithm for cable selection
For lines below 10mm2 (including 10mm2), the cross-sectional area of the wire multiplied by 5 is the current-carrying capacity of the cross-sectional area wire
The corresponding cross-sectional area is more than 100mm2 multiplied by 2
16mm2, 25mm2 times 4
35mm2, 50mm2 times 3
70mm2, 95mm2 times 2.5
If the wire goes through the tube and multiplied by the factor 0.8 (the total cross-sectional area of the wire through the tube does not exceed 40% of the cross-sectional area of the tube)
Multiplying coefficient 0.9 for use in high temperature places (within 85 degrees Celsius)
The cross-sectional area of bare wire (such as overhead bare wire) is multiplied by the corresponding magnification and then multiplied by 2 (such as 16mm2 wire: 16*4*2)
The above is calculated based on the cross-sectional area of the aluminum wire
Copper wire upgrade means that the carrying capacity of 1.5mm2 copper wire is equal to the carrying capacity of 2.5mm2 aluminum wire, and so on.
Sichuan Renyi Electric Co., Ltd. is registered under the name of Ren Yi, a senior technician for substation maintenance, and uses scientific research, knowledge innovation, publicity, promotion, and teaching that the temperature of electrical contacts (connectors) is lower than the temperature of its conductors (wires). The theory and technology of "thermal electrical contacts" produces and sells registered trademark electrical equipment that does not heat electrical contacts (joints), as a whole with patented products.