Forums » Electrical Engineering

NEC article 630 and 430

    • 4 posts
    January 9, 2020 7:26 AM PST

    currently there are 4 elevator motors. NEC article 630 asking for 0.77 demand factor and article 430 asks to apply 25%. to the largest motor.
    If the motors are same size around 20kW, which factor should be applied first 0.77 or 25%?

    • 157 posts
    January 9, 2020 5:56 PM PST

    Firstly, it is article 620 Not 630.  The demand for 4 elevators in T. 620.14 is 85% not 77% but that is only if the elevators meet the criterion of being half time on and half off-- 50% duty cycle.  If not then you would use the largest motor at 125% plus the sum of the other motors.

    IMO, you would not use both demands- one or the other.  To be safe use the 125% of the largest plus the sum of the others.

    Usually motors are rated in FLA or HP not KW