Estimation formula:

Multiply it by nine under 2.5, subtract one straight number up and go.

Thirty-five times three-and-a-half, and subtracting one-point five in pairs.

Conditions are subject to change plus discount, high temperature 10% off copper upgrade.

The number of pipes passing through is two, three or four, and the full load is 876%.

illustrate:

The formula in this section does not directly indicate the current carrying capacity (safe current) of various insulated wires (rubber and plastic insulated wires), but expresses it by multiplying the cross section by a certain multiple, which is obtained by mental calculation.

"Multiplying 2.5 times by 9, subtracting 1 and going up" refers to aluminum core insulated wires with various cross-sections of 2.5mm and below, and the current-carrying capacity is about 9 times the number of cross-sections.

Such as 2.5mm' wire, the current carrying capacity is 2.5×9=22.5(A).

The relationship between the ampacity and the number of sections of wires from 4mm’ and above is the upward row along the line number, and the multiple is successively reduced by l, that is, 4×8, 6×7, 10×6, 16×5, 25×4.

"Fifteen times 3.5, minus 5 in pairs" means that the current carrying capacity of a 35mm" wire is 3.5 times the number of sections, that is, 35 × 3.5 = 122.5 (A).

For wires of 50mm' and above, the multiple relationship between the current carrying capacity and the number of sections becomes a group of two wire numbers, and the multiple is reduced by 0.5 in turn. That is, the current carrying capacity of the 50 and 70mm' conductors is 3 times the number of sections; the current carrying capacity of the 95 and 120mm" conductors is 2.5 times the number of cross sections, and so on.

"Conditions are changed and discounted, and high-temperature copper upgrades are 10% off." The above formulas are determined by the aluminum core insulated wire and the open lay at the ambient temperature of 25 ℃.

If the aluminum core insulated wire is laid openly in the area where the ambient temperature is higher than 25 ℃ for a long time, the current carrying capacity of the wire can be calculated according to the above formula, and then 10% off; when the copper core insulated wire is not used, the Its current carrying capacity is slightly larger than that of aluminum wire of the same specification. For example, the current carrying capacity of 16mm' copper wire can be calculated as 25mm2 aluminum wire.