Calculating cable weight

Discussion in 'General Electronics Chat' started by crossj3, Jul 13, 2018.

  1. crossj3

    Thread Starter New Member

    May 10, 2018
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    Hi all

    Currently installing a machine and need to know the cable weight required.

    400v supply from a generator
    Machine has total of 50 kw of motors on it.
    The distance between the machine and power source is 35meters.

    How do I calculate the cable size required?
    I think it's 35mm squared cable. Am I right?
    Thanks
     
  2. BR-549

    AAC Fanatic!

    Sep 22, 2013
    4,065
    1,059
    Do you mean cable or wire size? And it could depend on physical lay-out. What is the normal temp in that 35 meters?

    Are you sure of that 400V figure? AC generator?
     
  3. BR-549

    AAC Fanatic!

    Sep 22, 2013
    4,065
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    Or do you mean the actual physical weight........as for stringing on poles?
     
  4. crossj3

    Thread Starter New Member

    May 10, 2018
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    Basically looking for the wire size of each core.
    Working in 20 degrees Celsius all the time .
    Thanks

     
  5. BR-549

    AAC Fanatic!

    Sep 22, 2013
    4,065
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    I suggest you google "conductor vs current" and look at some wire charts in your language. It will be a large size. Don't forget to look at and figure out the voltage drop for 35 meters.

    You might need to buy larger size than you realize.
     
  6. MaxHeadRoom

    Expert

    Jul 18, 2013
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    I can see #1.0 AWG for motor loads, is this above or underground?
    43mm2 to 33mm2.
    Max.
     
  7. MaxHeadRoom

    Expert

    Jul 18, 2013
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    How many actual motors, can they be started in sequence or at random?
    Max.
     
  8. dl324

    AAC Fanatic!

    Mar 30, 2015
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    That's 125 amps...
    We call it gauge, not weight.

    For power distribution, I'd use 0 AWG.
     
  9. crossj3

    Thread Starter New Member

    May 10, 2018
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    There is 2 motors started one after another in sequence. One starts on star delta and the second one starts after
     
  10. crossj3

    Thread Starter New Member

    May 10, 2018
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    Perfect Thanks. Some people call it weight here in Ireland
     
  11. -live wire-

    Active Member

    Dec 22, 2017
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    Um... why are you working with HV and extremely high power when you don't even know how to figure out the required wire gauge? You could easily be killed by a shock or arc blast.
     
  12. Hymie

    Active Member

    Mar 30, 2018
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    Cable with a cross sectional area of 35mm˄2 (1 AWG) is adequate for a current of up to 125A.

    Given the cable length, and allowing a load margin you might consider 50mm˄2 (0 AWG) cable which can handle up to 160A.
     
  13. crossj3

    Thread Starter New Member

    May 10, 2018
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    I don't do the wiring. I sold the machine. I just have to supply a power cable with it and want to know which one to buy. An electrician installs it.
    I'm usually working with single phase and 12v.
     
  14. -live wire-

    Active Member

    Dec 22, 2017
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    Oh, ok.
     
  15. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Intended to be fed via conduit? Underground? Above ground?
    Max.
     
  16. crossj3

    Thread Starter New Member

    May 10, 2018
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    Overground. Mounted on wall brackets. Open to the air I suppose.
     
  17. -live wire-

    Active Member

    Dec 22, 2017
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    Also make sure there is good, thick, durable insulation. You don't want to go too cheap and have an arc blast or short. You will also need a lot thicker than you may think to have a safe margin. If there are any really HV transients, an arc could be established and maintained with the normal voltage. Even with good snubbers, there is always the chance a HVAC motor will create huge voltage spikes.
     
  18. MaxHeadRoom

    Expert

    Jul 18, 2013
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    What about all the termination enclosures etc?
    Max.
     
  19. crossj3

    Thread Starter New Member

    May 10, 2018
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    On one end cable goes straight to generator poles.
    On The other end the cable goes straight onto the main isolator switch in the machine panel. Enters the panel through a grommet and is bolted onto the isolator bars for each phase. Fused after the isolator.
     
  20. MaxHeadRoom

    Expert

    Jul 18, 2013
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    If you have an electrician installing this I would have thought he could have spec'd in the cable?
    Simple grommet for 400v cable?
    It has been many decades since I did this kind of work in the U.K. but things must have changed.:oops:
    Max.
     
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