PROBLEM: Find the size THW copper conductors required to supply these motors.
STEP 1: NEC Table 430-150. The full-load current ratings of the motors are:
| Horsepower
| Amps
|
| 10
| 14
|
| 15
| 21
|
| 20
| 27
|
STEP 2: NEC 430-24.
Add 125% of the full-load current rating of the largest motor plus the full-load current rating of the remaining motors.
| 125% x 27 amps
| =
| 33.75 amps
|
|
|
| 21.00 amps
|
|
|
| 14.00 amps
|
|
|
| 68.75 amps
|
STEP 3: NEC Table 310-16
ANSWER: Size #4 THW copper conductors are required.
