# Calculating cable current carrying capacity

1. ## Calculating cable current carrying capacity

I wanted to calculate theoretically current carrying capacity of cable. I have 24 Awg cable. Which is having 8 strands . overall dimension of the cable is 1.27mm and each strands dia 0.015 mm approximately. Now i need relation equation to calculate current carrying capacity of it. Sine i dont have datasheet can someone guide equation for calculating it.

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3. ## Re: Calculating cable current carrying capacity

Originally Posted by nayakajit87
I wanted to calculate theoretically current carrying capacity of cable
In practice you do not calcultate the maximum current to carry on a wire, but rather the allowed heating and/or the allowed voltage drop due to the cable resistivity multiplied by its length, so there is no closed answer to your question.

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4. ## Re: Calculating cable current carrying capacity

The numbers mentioned in post #1 don't fit usual cable dimensions, except for the overall diameter.

24 AWG cable has cross section of about 0.22 to 0.3 mm², depending on the stranding. 7 strands (7/32) is a popular cable type, each strand having a diameter of 0.203 mm.

5. ## Re: Calculating cable current carrying capacity

Which is having 8 strands
this is a very uncommon number. The number of strands is usually decided by geometrical considerations: How many identical circles you can fit into a bigger circle with minimum waste of space.

Measure the resistance and calculate the dissipation for a given current. Also determine the thermal resistance of the insulation. Estimate the steady state temp of the cable for the given current.

Another important parameter may be permissible voltage drop. Even if your cable can take the current, the voltage drop may not be acceptable.

If you are using the bare wire as a fuse, other considerations may apply.

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6. ## Re: Calculating cable current carrying capacity

It is really important to know the kind of operation of the electric current flowing in that wire, whether in continuous or pulsed mode, which would still subject the conduction profile to an effectively smaller area, overheating for a short period the area near the insulation material. In short, the information given so far does not give a complete sight of what needs to be sized.

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