Forums » Electrical Engineering

cable loading

    • 13 posts
    May 10, 2019 10:28 AM PDT

    Does it make sense to load an electrical feeder or cable 100%, even it is operating continuously ?

    This post was edited by Syed Faraz at May 10, 2019 10:29 AM PDT
    • 15 posts
    May 10, 2019 10:32 AM PDT


    • 13 posts
    May 10, 2019 10:39 AM PDT

    thank you.

    • 25 posts
    May 10, 2019 10:48 AM PDT

    neither the ampere rating of the overcurrent device nor the ampacity of the feeder conductors shall be less than the noncontinuous load plus 125 percent of the continuous load.

    This post was edited by David Welson at May 10, 2019 10:49 AM PDT
    • 157 posts
    May 10, 2019 11:06 AM PDT

    I agree with everyone however there is one situation where it is allowed and that is if the breaker is rated for 100% at continuous operation.  There are very few breakers that are made this way and they usually are very large size breakers

    • 71 posts
    May 10, 2019 11:38 AM PDT

    Based on my experience, cable can be loaded  100%, only if the all reduction factors included during sizing a cable.

    The main reason not to load a cable 100% is, the age of cable will decrease.

    • 157 posts
    May 16, 2019 3:59 AM PDT

    My response earlier was about a breaker loaded 100% however there is no reason that a feeder cannot operate at 100%.  With 90C insuation there should not be an issue