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How do I determine what wire gauge to use?

  1. Dec 13, 2012 #1
    I have a motor that I am using, and I need to know what gauge wire to use to connect to the motor. I've looked all over online, but haven't found anything that can tell me a formula or anything to use to figure this out.

    The motor is 24VDC and draws 50A max, and would be running about 15 mins per hour of product use. The cable length is approx 10 ft. Is there any more information required to determine what gauge wire I should use?
  2. jcsd
  3. Dec 13, 2012 #2


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    There are tables of current handling capacity for a whole range of cable gauges, available. A google search for "Wire Gauge current rating" will yield a load of possible links.
    The insulation and proximity to similar cables will have as much relevance as the simple current rating of the wire, though. For instance, drums of extension cable need to be protected from overheating when operated with most of the cable actually on the drum.
    It is simpler to buy cable which is rated (on the pack) for the current that you want to use (erring on the large size if there is any doubt). That will enable you feel confident that it will not overheat. Forget about the duty cycle unless there is a serious reason for 'pushing your luck' and cutting down on cost. Just select 50A cable from a catalogue (which I expect will be 10mmsq) and then you won't need to worry. It will be annoyingly expensive but 50A is quite a heavy load (typical Electric Shower Power cable)
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