How to calculate the amount of load current of copper core?

In fact, these data, you can check the "Electrician Practical Manual", in practical application, the current amount of the load should be smaller than the theoretical data, because, to consider the way the wire is laid, the length of the line, the quality of the copper wire and other factors such as mechanical strength and so on, can not be a sigh.

Only know the commonly used 1-10 square ones. If there are less than 10 wire cross-sections, the current is 5 times that of the cross-section, e.g., 6=30A

The current carrying capacity of copper core cable is as follows:

<> cable current carrying capacity refers to the amount of current passed by a cable line when transmitting electric energy, and under thermally stable conditions, when the cable conductor reaches the long-term allowable operating temperature, the cable current carrying capacity is called the long-term allowable current carrying capacity of the cable.

The comparison table of copper wire diameter and bearing current is as follows:

1. For mm2 wires, the cross-sectional area can be multiplied by 5 times.

2. For mm2 wires, the cross-sectional area can be multiplied by 4 times.

3. For mm2 wires, the cross-sectional area can be multiplied by 3 times.

4. For mm2 wires, the cross-sectional area can be multiplied by the crack difference.

5. For mm2 wires, the cross-sectional area can be multiplied by 2 times.

6. Power p = voltage u current i 220 volts stupid 18 amps 3960 watts.

The general copper wire safety calculation method is:

1 square millimeter 10a

16a square millimeter

The safe ampacity of the square millimeter copper power cord is 28A.

The safe ampacity of the 4 square mm copper power cord is 35A.

The safe ampacity of the 6 square mm copper power cord is 48A.

The safe ampacities of the 10 square mm copper power cord are 65A.

The safe ampacity of the 16 square mm copper power cord is 91A.

The safe current carrying capacity of the 25 square mm copper power cord is 120A.

If it is an aluminum wire, the wire diameter should be times that of the copper wire.

If the copper wire current is less than 28A, it is definitely safe to take 10A per square millimeter.

If the copper wire current is greater than 120A, it will be taken as 5A per square millimeter.

The current that can pass through the cross-sectional area of the wire can be selected according to the total amount of current that needs to be conducted, and can generally be determined according to the following smooth slip:

Ten under five, one hundred on two, two five three, five five, five five, five five and a half times, copper wire upgrades.

Let me explain to you, it is an aluminum wire of less than 10 square meters, multiply the number of square millimeters by 5, if it is a copper wire, it will be upgraded by a gear, such as a square copper wire, it will be calculated according to 4 square meters. More than 100 are multiplied by 2 for the cross-sectional area, multiplied by 4 for those below 25 square meters, multiplied by 3 for more than 35 square meters, and multiplied by 95 square meters.

The safe ampacity of the current carrying capacity of the copper conductor is determined according to the allowable high temperature, cooling conditions and laying conditions of the core. Generally, the safe current carrying capacity of copper wire is 5 8a mm2, and the safe current carrying capacity of aluminum wire is 3 5a mm2. Generally, the safe current carrying capacity of copper wire is 5 8a mm2, and the safe current carrying capacity of aluminum wire is 3 5a mm2.

Calculate the cross-sectional area of the copper conductor using the recommended value of the safe ampacity of the copper conductor 5 8A mm2, and calculate the upper and lower ranges of the selected copper conductor cross-sectional area S: s=[i (5 8)] = cross-sectional area of the copper conductor (mm2)i--- load current (a).

Power calculation: General loads (which can also be used as electrical appliances, such as lights, refrigerators, etc.) are divided into two types, one is a resistive load, and the other is an inductive load. Formula for resistive load: p=ui Formula for fluorescent lamp load:

p = uicos, where the power factor cos = of the fluorescent lamp load. The power factor of different inductive loads is different, and the power factor cos can be taken when the household appliances are calculated in a unified manner.

That is to say, if all the electrical appliances in a household plus the total power is 6000 watts, the maximum current is i=p ucos =6000 220*However, under normal circumstances, it is impossible to use the electrical appliances in the home at the same time, so add a common factor, and the common coefficient is average.

Therefore, the above calculation should be rewritten as i=p*common-coefficient ucos =6000*, i.e., the total current value of the family is 17a. Then the main gate air switch can not use 16A, should use greater than 17A.

To calculate the current that a copper wire can withstand, we need to know the resistivity of the copper and the cross-sectional area of the copper wire.

The resistivity of copper is usually expressed as (unit: ·m). At room temperature, the resistivity of copper is about x 10 m.

The cross-sectional area of the copper wire can be expressed in square millimeters (mm). It is known that the cross-sectional area of copper wire is 10 mm.

To calculate the current that a copper wire can withstand, we can use Ohm's law:

Current (i) = Voltage (V) Resistance (R).

where the resistance (r) can be calculated by resistivity ( ) and length (l) in terms of the area of rent and cut-off yards (a).

r = l / a)

Since the length of the copper wire (l) is not provided, the specific current cannot be calculated. But if you have voltage and length information, you can use the above formula to calculate the current that the copper wire can withstand. Please make sure that the rated current of the copper wire is not exceeded in the actual application to prevent overload and overheating.

The power corresponding to the square of the copper wire is calculated according to the current, which is divided into two algorithms: 1. The current carrying capacity of the wire can be obtained by the blind meter method, which is convenient and intuitive. 2. It is obtained by the calculation method.

It is known that the cross-sectional area of pure copper wire is s(mm), the general current density is 6a mm, and the current carrying capacity of the wire is i(a)=s(mm)*6a mm.

For example: a square wire, which has a maximum ampacity of i. In the case of 220V voltage, the maximum carrying power is P 220x15 3300 (W).

At 2.5 p.m., take the disturbance omen to nine, and go up and minus one order. Thirty-five times 3.5, double in a group minus five. The conditions have been changed and converted, and the high-temperature nine-fold copper has been upgraded. The number of pipe roots is two, three, four, eight, seven and six folds full of load current.

Note: The current carrying capacity (safety current) of various insulated wires (rubber and plastic insulated wires) is not directly indicated in this formula, but is expressed by "multiplying the cross-section by a certain multiple", which is obtained by mental arithmetic. Grinding Li didn't.