How many amps a single core wire of 1mm can pass through in open air or i.e. open n?

[munzir]

How many amps a single core wire of 1mm can pass through in open air or i.e. open not concealed ?

And would the withstanding amps (amps that will flow through the wire) increase or decrease by increasing the cores ?

which one cable can pass through max. amps ?

1) 1 mm single core
2) 1 mm 2 core
3) 1 mm 3 core
4) 1 mm 3.5 core
4) 1 mm 4 core


Thanks

 

[Usama Siddiqui]

the more cores there are the more amps it could withstand,basically it depends upon the parallel paths,if you wanna increase the current rating of any circuit what is done is just to increase the parallel paths.

 

[ahsan_i_h]

The question actually means
"which one cable can pass through max. amps per core?"

 

[munzir]

means the amps that 4 core 1 mm cable can easily pass through it is 4 times the amps that 1 core 1 mm cable can pass through it , right ????

 

[tpetar]

What you mean under core number ?

We speak about standard multi core AC cables (1,2,3,5 cores) ? or we speak about multicore cables for special purposes ?

Cable with single core can carry more amps then others, and withstand higher temp. But if you use all cores as one then this is logical answer, but its bad and dangerous solution. Paralleling cores is dangerous if they are not linked as braid.



Best regards,
Peter

 

[kripacharya]

The current rating of a conductor is based on how hot it is allowed to get before being considered too hot.
Hence current rating also depends on how its cooled - i.e. enclosed in insulation or open air, and the temperature of the air. Also the material it is made of.

Typically this is specified as a max of 30C rise above an ambient of 40C.

A 1mm dia wire is around 18 AWG, and can carry about 16amps (copper wire)

If this same dia is split into more pieces, then the total copper is reduced, hence the current ability is reduced. So the answer is (1) 1mm single core.

If multiple cores are used - each of dia 1mm - then naturally the current capacity will increase in proportion.

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means the amps that 4 core 1 mm cable can easily pass through it is 4 times the amps that 1 core 1 mm cable can pass through it , right ????

no thats incorrect.

 

[munzir]

The current rating of a conductor is based on how hot it is allowed to get before being considered too hot.
Hence current rating also depends on how its cooled - i.e. enclosed in insulation or open air, and the temperature of the air. Also the material it is made of.

Typically this is specified as a max of 30C rise above an ambient of 40C.

A 1mm dia wire is around 18 AWG, and can carry about 16amps (copper wire)

If this same dia is split into more pieces, then the total copper is reduced, hence the current ability is reduced. So the answer is (1) 1mm single core.

If multiple cores are used - each of dia 1mm - then naturally the current capacity will increase in proportion.

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no thats incorrect.

with dia are you considering the different insulations also ?

means the amps that 4 core 1 mm cable can easily pass through it is 4 times lesser than the amps that 1 core 1 mm cable can pass through it , right ????

Thanks

 

[kripacharya]

with dia are you considering the different insulations also ?

means the amps that 4 core 1 mm cable can easily pass through it is 4 times lesser than the amps that 1 core 1 mm cable can pass through it , right ????

Thanks

Now this is getting confusing. Lets just simplify everything for you :

If the cross-sectional area of your conductor is larger, then the current capability is larger. That's all.

 

[ahsan_i_h]

I have uploaded few scanned pages(four) from a cable manufacturer's catalog

Cables are selected based on the cross sectional area of one core. And current rating means allowable current in one core
when all other cores are carrying the equal amount of current.

from the image(single_core) we see 1.5mm2 single core cable(first row) can carry 22A in air
from the image(two_three_core) we see 1.5mm2 two core cable(first row) can carry 19A in air
from the image(two_three_core) we see 1.5mm2 three core cable(first row) can carry 16A in air
from the image(four_core) we see 1.5mm2 four core cable(first row) can carry 16A in air

So four core cable (in each core) can carry less current than single core cable.It is due to, all hot cores in one place will cause
more temperature. So current is reduced to down the temperature.

means the amps that 4 core 1 mm cable can easily pass through it is 4 times the amps that 1 core 1 mm cable can pass through it , right ????

The answer is no. It is 4*16/22 equals to 2.9 times. But cores are not usually used as parallel to increase current.

 

[FvM]

Referring to "ampacity" tables and it's derating according to number of circuits would be also my general answer. https://en.wikipedia.org/wiki/Ampacity

1 mm wire diameter refers to about 0,75 mm².

As already mentioned, the standarized rating applies for standard conditions, so you possible arrive at different values for a specific application that doesn't need to respect general regulations.

 

[ahsan_i_h]

I agree. I should mention in the previous post about 1.5mm2 as an example.
Basically the second, third and fourth questions of the original poster is independent of cable size, so example of 1.5mm2 cable will do the same.
For first question, current rating of 0.75mm2 cable can be found by halfing the current rating of 1.5mm2 cable. Or he may ask. Besides it seems
main interest of op is on second, third and fourth question.

 

[munzir]

Referring to "ampacity" tables and it's derating according to number of circuits would be also my general answer. https://en.wikipedia.org/wiki/Ampacity

1 mm wire diameter refers to about 0,75 mm².

As already mentioned, the standarized rating applies for standard conditions, so you possible arrive at different values for a specific application that doesn't need to respect general regulations.

Can we calculate amps in each core of a multi-core cable ?

If 3 core cable of 1.5 mm size can withstand 17 amps in open air then almost 6 amps are passing through each of the three cores or 17 amps current is passing through each cores ?

Thanks in advance

 

[kripacharya]

I think this line of homework questions is getting a little out of hand.

 

[munzir]

I agree. I should mention in the previous post about 1.5mm2 as an example.
Basically the second, third and fourth questions of the original poster is independent of cable size, so example of 1.5mm2 cable will do the same.
For first question, current rating of 0.75mm2 cable can be found by halfing the current rating of 1.5mm2 cable. Or he may ask. Besides it seems
main interest of op is on second, third and fourth question.

Can we calculate amps in each core of a multi-core cable ?

If 3 core cable of 1.5 mm size can withstand 17 amps in open air then almost 6 amps are passing through each of the three cores or 17 amps current is passing through each cores ?

Thanks in advance

 

[FvM]

The "ampacity" numbers as e.g. listed in post #9 are meaned per wire. Or 17 A per core in your example.