Cross-section and diameter of the cable. Diameter 2.5mm into mm

Question

I would like to know if I am calculating the cross-section of the cable correctly.
I have a cable with a diameter of 2.5mm (measured wire without insulation).
I substitute it into the formula for the area of a circle, and the cross section comes out?
P= 3.14xdiameter? ?
P=3.14x2.5x2.5
P=19.6mm?

Is that how it's measured?
I have doubts because the cable seems too thin for me to use.
What is the safe strength of such a cable?

kkas12 · Answer

The formula for the area of a circle: P = ? o r2 Question: what is r???

awow · Answer

The cross-sectional area of the conductor, for a diameter of 2.5mm, is 4.91mm?. It should be added that the diameters of the wires are standardized and the closest are 4 or 6mm?.

Matikqw · Answer

Oh right. Stupid mistake. It's a quick calculation. So thanks thanks. And if I have it 4.91, I round it to 4mm?? It's begging for 5mm? more

DiZMar · Answer

S = ?r? = ?(d/2)?. Where S - area in mm?, ? - 3.14 r - radius in mm d - diameter in mm For you, d = 2.5, so the area S = 3.14 x 1.25? = 4.91 mm?. That's the whole philosophy.

kkas12 · Answer

Is there such a cable?

jurek849 · Answer

You're doing it wrong, the formula for the area of a circle is 3.14 x r squared, which is 3.14 x 1.25 x 1.25 = 4.9 mm?. The current density depends on the material of the cable, /copper or aluminum/ and the type of device, type of load.

slawekx · Answer

The formula for the area of a circle is:

P=?r?

Explanation of symbols:

P - area of the circle

r - radius of the circle

A circle with center O and radius r (r > 0) is the set of points in the plane whose distances from O are less than or equal to r.

DiZMar · Answer

Calculated on the basis of the topic author's data. The fact that there is no such cable does not mean that the author of the topic should not be led out of the wrong calculation based on the data provided by him. Probably his diameter is 2.256 mm and not 2.5 mm, and then a wire with a cross-section of 4 mm? or 2.764 mm and a cross-section of 6 mm?. Or maybe he invented these 2.5 mm in diameter? He supposedly wrote that the cable measured without insulation. I wonder what he measured? Maybe a ruler with a scale with an accuracy of 1 mm? He assessed these 0.5 mm by eye.

Rasel · Answer

Maybe it's winding wire? There is such a copper wire with a diameter of 2.5 mm.

DiZMar · Answer

And there's the answer. I admit I didn't know about it.

kkas12 · Answer

You know what measurement such calculations. As a result, neither one nor the other is worth anything.
And even if junior high school exams are postponed, it doesn't mean that you can't apply the formula for calculating the area of a circle by putting an equal sign between the diameter and the radius.

From the title of the thread, it does not appear that the author had winding wire in mind.

DiZMar · Answer

You sound like a politician. A specific question and he talks about side topics all the time he spends on it.

kkas12 · Answer

The whole thread only shows that neither the measurement nor the calculations were done correctly.
In the case of measurement, inaccuracy and in the case of calculations, words are missing.
And it's in the professional section.

Matikqw · Answer

Today, I quickly measured with a caliper, but it was definitely closer to 2.5mm. I will measure again to clear my doubts. If you write that the calculation is wrong, please do it right, because I don't understand where the error is (of course not in my calculations, but in other users' calculations)

kkas12 · Answer

If diameter and radius are the same for you, congratulations on your uncritical approach.
And a nonchalant approach to measurement results in an incorrect result of my friend's calculations, which can be seen from their result, because a wire with such a cross-section does not exist.

Matikqw · Answer

I know it's not the same. I do not deal with this on a daily basis and I approached the calculations quickly, so it's my stupid mistake, which I admitted earlier. So much. I'll measure the diameter tomorrow and let you know.

Rafael22 · Answer

A little cheat for posterity

CYRUS2 · Answer

Depends on what the author is measuring. Doubtful that I micrometer. If the measurement result is 2.4 instead of 2.5, the calculated cross-section is 4.32mm?. The cross-section is not important, only the resistance of the length of the conductor. I measured it. In many cases, the resistance was lower than it appears from the declared cross-section. Declared - the measurement error of the cross-sectional area is eliminated.

DiZMar · Answer

Maybe the copper was of a higher quality than expected or the cross-section was with a positive tolerance? So he led better than the parameters give. There was no danger, because the project, even in nominal acceptable values, was becoming a margin. Usually the declaration is better than the reality. Here reality is better than declaration.

pejan 123 · Answer

I am still asking for help in determining the cross-section of the cable at the connection to the house.
The cable is aluminum 4x? but its cross-section is close to a triangle. I measured with a caliper and it is about 4mm at the widest point.
Will it be something around 4x10 or maybe due to the triangular shape not round it will be 4x16?

krzysiek7 · Answer

Personally, I have never come across a 10 mm square sector, and 16 definitely. If the connection was made not long ago, 10 is not realistic. For many years, the minimum cross-section of an AL conductor has been 16 square mm.

pejan 123 · Answer

I thought so too. This is good news for me. Thanks.

Cross-section and diameter of the cable. Diameter 2.5mm into mm

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