How can we calculate the current (I) if we have cable with 25 mm size for 480V?

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    Cable Current
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Discussion Overview

The discussion revolves around calculating the current (I) for a cable with a cross-sectional area of 25 mm² when supplied with 480V. Participants explore parameters influencing this calculation, including load considerations and cable specifications.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant inquires about the method to calculate current for a 25 mm cable at 480V, asking if other parameters are necessary.
  • Another participant questions whether the inquiry pertains to the maximum safe current for the cable size or the current during a short circuit.
  • A participant clarifies that the current carried to a load is primarily determined by the load itself, not just the cable size, while emphasizing the importance of ensuring the cable can handle the current to avoid damage.
  • There is a request for clarification on whether "25 mm" refers to diameter or cross-sectional area, which is confirmed to be 25 mm².
  • A participant references American Wire Gauge (AWG) standards, suggesting that 25 mm² is equivalent to 3 to 4 AWG cable and notes the importance of considering insulation temperature ratings and voltage ratings for safety.
  • Links to external resources are shared for further information on calculating voltage drop and current control.

Areas of Agreement / Disagreement

Participants generally agree on the need to consider load when determining current capacity, but there is no consensus on the specific maximum current for the 25 mm² cable, and the discussion remains unresolved regarding the exact parameters needed for calculation.

Contextual Notes

Limitations include the lack of specific load values and the need for additional parameters such as temperature ratings and insulation specifications, which are not fully addressed in the discussion.

megatronic
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dear engineer,

how can we calculate the current (I) if we have cable with 25 mm size for 480V?
and are there any other parameters we should know to calculate the current.


(for plant project purpose)
 
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Are you asking what the maximum safe current is for this size of cable, or asking how much current you have when you short out 480V with a segment of this cable?

If you're asking how much current is carried to a load when using a 480V supply, this is determined chiefly by the load, and not the cable (though clearly, you need to ensure that the cable can carry that current, otherwise you'll just have burnt / melted cable)
 
thanx MATLABdude, you are right the cable should be chosen by considering the load and the current carried to the load.
however what I meant is the maximum current appropriate for this size of cable.
 
megatronic said:
thanx MATLABdude, you are right the cable should be chosen by considering the load and the current carried to the load.
however what I meant is the maximum current appropriate for this size of cable.

Is 25 mm the diameter or do you mean 25 mm^2 for the cross-sectional area?

CS
 
stewartcs said:
Is 25 mm the diameter or do you mean 25 mm^2 for the cross-sectional area?

CS

the cross section 25mm^2
 
That sounds like it's somewhere between 3 and 4 AWG cable:
http://en.wikipedia.org/wiki/American_wire_gauge

The ampacities are listed for various insulator temperature ratings. You also need to ensure that the jacket is rated for the voltage that it's carrying (otherwise, you might have arcing through the insulation between cables lying side by side).
 
thanx MATLABdude the link will be useful
 
visit this site.
Simply and quickly..

http://www.incable.somee.com

calculating drop-voltage, current control
 
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