I am looking for an extra set of eyes on sizing of the conductors for a 460V 3ph 100 hp continuous duty motor with a pf of .87 and a nameplate amp rating of 115A. The circuit is run in emt, ~50ft and in 74 deg F space.
Per 430.6 (A)1 I am using table 430.250 to determine motor FLA. The 460V column = 124A
The *note below the table states that for a motor with a pf of .9 multiply the value by 1.1 and for .8 pf motors multiply by 1.25
430.22 states that for continuous use motors conductors need to be 125% of ampacity as determined by 430.6 (A)1
I believe that the correct calculation is 124A *125% = 155A resulting in a 2/0 THW conductor for a 75 deg termination.
I want make sure that based on the pf of the motor that I don't need to multiply the 124A by the pf note below table 430.250 and then take 125% of that value. As you know, this wire size will be much higher.
Per 430.6 (A)1 I am using table 430.250 to determine motor FLA. The 460V column = 124A
The *note below the table states that for a motor with a pf of .9 multiply the value by 1.1 and for .8 pf motors multiply by 1.25
430.22 states that for continuous use motors conductors need to be 125% of ampacity as determined by 430.6 (A)1
I believe that the correct calculation is 124A *125% = 155A resulting in a 2/0 THW conductor for a 75 deg termination.
I want make sure that based on the pf of the motor that I don't need to multiply the 124A by the pf note below table 430.250 and then take 125% of that value. As you know, this wire size will be much higher.
