Three minutes learn the wire to withstand the current estimation, knowing this is called electricity

Work temperature is 30 ° C, and the amount of carrier flow under the long-term continuous 90% load is as follows:

1.5 square millimeters – 13A

2.5 square millimeters – 26A
4 square millimeters – 32A

6 square millimeters – 47A
16 square millimeters – 92A

25 square millimeters – 1220A

35 square millimeters – 150A

Current conversion power:



So on and so forth.

For example, if the carrier traffic is 14A, it is: 220W × 14=3080W, then 1.5 square copper wire power is 3.08 kW.

Long-term current allowed by national standard:

4 square is 25-32A

6 square is 32-40A

In fact, these are the theoretical security values, and the limit value is more than these.

The maximum power allowed by the 2,5 square copper wires is: 5500W.

4 square 8000W, 6 square 9000W is no problem.

40A’s digital meter is normal 9000W absolutely no problem. The 12000W of the machine will not be burned.


Copper wire wires allow long-term current:

2.5 square millimeters (16A ~ 25A)
4 square millimeters (25A ~ 32A)
6 square millimeters (32A ~ 40A)

for example :

1. Each computer consumes approximately 200 ~ 300W (about 1 to 1.5a), then 10 computers need a 2.5-square millimeter copper wire power supply, otherwise a fire may occur.

2, the large 3 air conditioner consumption is approximately 3000W (about 14a), then one air conditioner requires a separate 2.5 square millimeter copper wire power supply.
3, the current housing outlet is generally 4 square millimeters of copper wire, so the home appliances open at the same time must not exceed 25A (ie 5500 watts), some people replace the wires in the house to 6 square millimeters copper wires are useless. Because the wires entering the meter are 4 square millimeters.
4. Early housing (15 years ago) The import line is generally 2.5 square millimeter aluminum wire, so the home appliances open at the same time must not exceed 13A (ie 2800 watts).

5, household appliances that are relatively large consumption are: air conditioner 5a (1.2), electric water heater 10a, microwave oven 4a, rice cooker 4a, dishwasher 8a, drying machine 10a with drying function, electric heater 4a.

Among the fire caused by the power supply, it is due to the heat of the hair, so all the joints must be welded, and the contact devices that cannot be welded 5 to 10 years must be replaced (such as socket, air switch, etc.).


Copper wire wire cable traffic standard cable flow oral estimation:

Take the next two o’clock in nine, and go to the next time.

Thirty-five take three o’clock, double bunom group is five.

The conditions have changed, and the high temperature is 10% off copper upgrade.

The number of tube is two or three four and eight seven six folds.


This mouth is not directly pointed out to various insulated lines (rubber and plastic insulation lines), but "cross-section is multiplied in a certain number" to be represented.

"Two five-point multiply by nine, go to the next time," said that various cross-sectional aluminum insulation lines of 2.5mm2 and below are about 9 times the number of carriers of the cross-section. Such as 2.5mm2 wires, the carrier flow is 2.5 × 9=22.5 (a). The multiple relationship between the carriage of 4mm2 and more wires and the number of cross-section is row, the line number is row, the multiple is successively reduced by 1, i.e., 4 × 8, 6 × 7, 10 × 6, 16 × 5, 25 × 4.

"Thirty-five Take Three Fiveth, Double Bunction] Say", it is said that 35mm2 lead traffic is 3.5 times the number of cross-section, ie 35 × 3.5=122.5 (a). Wire from 50 mm 2 and above, the multiple relationship between the amount of carrier flow and the number of cross-section becomes a set of two two lines, and the multiple is 0.5. That is, 50, 70mm2 wire has a total of 3 times the number of cross-section; 95, 120 mm2 lead traffic is 2.5 times the number of cross-sectional area, and push it according to the secondary.

"Conditions have changed, high temperature nine fold copper upgrades". The above mouth is the copper core insulation line, which is determined under the condition of 25 ° C in ambient temperature. If the aluminum core insulation line is in the area where the ambient temperature is higher than 25 ° C, the wire carrier flow can be calculated according to the above-mentioned oral calculation method, and then hits it again; when used is not an aluminum wire but the copper core insulation line, Its carrier flow is slightly larger than the same size aluminum wire, and can calculate a carrier flow than the aluminum wire in the above-mentioned oral method. For example, the flow of 25mm2 copper wire can be calculated according to 25 mm2 aluminum wire.


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