To give you an estimate formula:

Two point five times by nine, go up and down the number to go.

Thirty-five by three point five, both groups reduced by five.

Conditions have changed plus conversion, high temperature ten percent off copper upgrade.

Intubation root number two three four, eight seven forty percent off full flow.

Explain

(1) this section formulas of various insulation line (rubber and plastic insulated wire) load flow (current) is not directly pointed out, but "cross-section multiplied by a certain multiple" to express, through the mental arithmetic. It can be seen that the multiple decreases with the increase of cross section.

Two point five multiplied by nine, to go up and down the number to go "said the 2.5mm" and the following various sections of the aluminum core insulation line, the flow rate of about 9 times the number of cross section. Such as 2.5mm 'wire, load flow is 2.5 x 9 = 22.5 (A). From 4mm 'and above conductor ampacity and section number of the multiple relationship is along the line number to the row and multiple successive minus L, 4 x 8, 6 x 7, 10 x 10 6, 16 x 5, 25 x 4.

"Thirty-five times three point five, both groups of five reduction points," said the 35mm is the number of cross section of the wire 3.5 times, that is, 35 x 3.5 = 122.5 (A). From 50mm 'and above the wire, the ratio of the multiple relationships between the flow and the cross section is changed into a set of two two lines, and the ratio is reduced by 0.5. That is, 50, 70mm 'wire carrying capacity of 3 times the number of cross section; 95, 120mm "wire load flow is the number of its cross-sectional area of 2.5 times, and so on.

"Conditions have changed plus conversion, high temperature ten percent off copper upgrade". The above formula is aluminum core insulation wire, deposited in the environmental temperature of 25 DEG C under the condition of the. If the aluminum core insulation line next deposited at ambient temperature higher than the long-term area of 25 DEG C, carrying capacity of the wire, can according to the above formula is calculated, and then discount can; when not using aluminum but copper core insulated wires and the carrying capacity to slightly larger than the same specification aluminum, according to the above formula method to calculate than aluminum increase a line number of the current carrying capacity. If the flow load 16mm 'copper wire, according to the calculation of aluminum 25mm2.

**Up Page：**Process characteristics of wire and cable products

**Next Page：**Naming principles of electric wire and cable products