Power cord Ningbo Qiaopu Electric Co., Ltd., the cross-sectional area calculation method
Copper more coarse per square millimeter of a smaller ampacity, copper cross-sectional area (square): 1.0,1.5,2.5,4,6,10
PVC insulated wire wear plastic tube (three side-by-side wear), safety ampacity 11,15,21,28,36,49. Unit: Ann. (According to the above order)
Wear iron pipe than wearing a plastic tube about junior safety!
Plastic insulated wire and this is not it! Than this point! But under normal circumstances, the plastic insulated wire is rarely used, general-purpose PVC insulated wire!
10 under five, 100 on two, 16, 25 four, 35, 50, three, 70,95 two and half times.
Wear a tube, temperature 8 10% off, the bare plus half. Copper upgrade count.
Formulas in Arabic numerals with the arrangement of multiple relations as follows:
Wire 1.5,2.5,4,6,10 mm2 its cross-sectional area can be multiplied by 5 times.
16,25 mm2 wires can be multiplied by the number of cross-sectional area of ​​4 times.
35,50 mm2 conductors may be its cross-sectional area multiplied by 3 times.
70,95 mm2 wires can be multiplied by the number of cross-sectional area of ​​2.5 times.
120,150,185 mm2 wire to its cross-sectional area multiplied by 2

Plastic-carrying capacity of copper wire (security) table

Conductor cross-section (mm2) 1 1.5 2.5 4 6 10 16 25 35 50 70 95 120
BV root of the number of hard-line / single root diameter 1/1.13 1/1.37 1/1.76 1/2.24 1/2.73 7/1.33 7/1.68 7/2.11 7/2.49 19/1.81 19/2.14 19/2.49 37/2.01
Number of BVR root cord / single diameter 7/0.43 7/0.52 19/0.41 19/0.52 19/0.64 19/0.82 49/0.64 98/0.58 133/0.58 133/0.68 189/0.68 259/0.68 259/0.76
The open type ampacity (An) 5,101,525,356,090,113,140 177 268 288 314
Closed ampacity (An) 4 8 12 20 28 48 7,293,115,145,220,240,258

Wire cross-sectional area of ​​the load flow calculation

Usually copper wire ampacity conductors safe carrying capacity is determined according to the allowed maximum conductor temperature, cooling conditions, laying conditions. Usually a safe carrying capacity of the copper wire for 5 ~ 8A/mm2, and the the aluminum conductors security ampacity 3 ~~ 5A/mm2. The <key points in general copper wires safe carrying flow for 5 ~ 8A/mm2, and aluminum conductors safe carrying a flow rate of 3 ~ 5A/mm2,. As: safe carrying capacity of 2.5 mm2 BVV copper wire recommended value of 2.5 × 8A/mm2 = 20A 4 mm2 BVV the copper conductors security ampacity recommended values ​​of 4 × 8A/mm2 = 32A

Second, the calculation of the recommended values ​​of the copper conductor cross-sectional area of ​​the safety of using copper wire ampacity 5 ~ 8A/mm2, calculated copper conductor cross-sectional area S of the selected upper and lower range: S = <I / (5 to 8)> = 0.125 I ~~ 0.2 I (mm2) S ----- copper wire cross-sectional area (mm2) I ----- Load current (A)

Power calculation generally load (also can be divided into two, one-resistive load, electrical appliances, such as lighting, refrigerators, etc.) a inductive load. The For resistive load formula: P = UI for the fluorescent lamp load calculation formula: P = UIcosф, wherein the fluorescent lamp load power factor cosФ = 0.5. Different inductive load power factor, and unified computing household appliances can be the power factor cosф 0.8. That is if one household appliances with a total power of 6000 watts, the maximum current is I = P / Ucosф = 6000/220 * 0.8 = 34 (A), however, under normal circumstances, home appliances can not be used simultaneously plus a utility coefficient, utilities coefficient generally 0.5. Therefore, the calculation of the above should be rewritten as I = P * Utility coefficient / Ucosф = 6000 * 0.5/220 * 0.8 = 17 (A) In other words, the total current value of the family 17A. The total gate can not use the air switch 16A, should be greater than 17A.

Second, the copper wire ampacity (35 ℃) cross-section (mm2) 1 1.5 2.5 4 6 10 16 25 35 50 70 95 Ampacity (A) 10 13 17 23 30 45 85 110 136 170 216 263 three drawers drawer wire selection standard cross-section (mm2) 10 16 16 25 35 50 70 35 × 2 50 × 2 70 × 2 50 × 3 70 × 3 current (A) 50 63 80 100 125 160 200 250 300 400 500 60 <critical point