How to calculate the current carrying capacity of a wire?

『Calculation method for current carrying capacity of wires』Related information(clamp on meter|electromagnetic meter|venturi meterrotameter|orifice meter|ultrasonic flow meter|mass flow meter|coriolis mass flow meter|coriolis flow meter|magnetic flow meter|magmeter flow meter|magflow flow meter|mag meter flow meter|electromagnetic flow meter|vortex flow meter|turbine flow meter|thermal mass flow meter|thermal flow meter|rotameter flow meter)

How to calculate the current carrying capacity of a wire? The current carrying capacity of a cable is related to the cross-sectional area of the conductor, as well as the material, model, laying method, and environmental temperature of the conductor, and the calculation is also cumbersome. The current carrying capacity of various wires can usually be found in the manual. But by using mnemonics combined with some simple mental calculations, the current carrying capacity of the wire can be directly calculated, which is more convenient. Closed loop current carrying capacity is the maximum current that a conductor can continuously carry without causing its stable temperature to exceed the specified value under specified conditions. The approximate multiple relationship between wire cross-sectional area (mm2) and current carrying capacity (A) is commonly used for aluminum core wires. The approximate relationship between nominal cross-sectional area and current carrying capacity is as follows: Formula and explanation of the relationship between wire cross-sectional area and current carrying capacity. The current carrying capacity with a cross-sectional area of 100mm2 or more is twice the cross-sectional area value. 2

5, 35,

For the fourth and third boundaries with cross-sectional areas of 25mm2 and 35mm2, the current carrying capacity is at the boundary of 4 times and 3 times. 70, 95, with a cross-sectional area of 70mm

2, 95mm2, the current carrying capacity is 2.5 times the cross-sectional area. For conduit installation (including trough plates, etc.), where the wires are covered with protective sleeves and not exposed, the calculated current carrying capacity should be discounted by 20%; If the ambient

temperature exceeds 25 ℃, a 10% discount will be applied after calculation; If the temperature exceeds 25 ℃ during the installation of the pipe, it will be discounted by 20% and then another 10%, or simply calculated as a 30% discount per installation. Half of the bare wire is used to calculate the current carrying capacity of bare aluminum wire, and then half is added. This refers to the fact that the current carrying capacity of bare aluminum wire with the same cross-sectional area can be increased by half compared to aluminum core insulated wire. For example, the calculation of the current carrying capacity of bare aluminum wire: when the cross-sectional area is 16mm2, the current carrying capacity is 16 × 4 × 1.5=96A. If it is at high temperature, the current carrying capacity is 16 × 4 × 1.5 × 0.9=86.4A. For example, with a cross-sectional area of 35mm2 bare copper wire and an ambient temperature of 25 ℃, the calculation of current carrying capacity is: upgrading to 50mm2 bare aluminum wire yields 50 × 3 × 1.5=225A. Error explanation: From the above content, it can be seen that the current carrying capacity of the wire decreases with the increase of cross-sectional area, and the error is slightly larger at the junction of multiple transformation. For example, the cross-sectional areas of 25mm2 and 35mm2 are at the boundary between 4 and 3 times. 25mm2 belongs to the range of 4 times, which is calculated as 100A according to the formula but 97A according to the manual; while 35mm2 is the opposite, calculated as 105A according to the formula but 117A according to the table. However, this has little impact on usage.

III. Safety current carrying capacity of general copper conductors The safety current carrying c

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