To calculate the minimum circuit ampacity (MCA) for an air-conditioning unit with more than one motor, we use the following method:
1. Identify the largest motor's amp draw - Among all the motors in the air-conditioning unit, find the one with the highest amp draw.
2. Multiply the largest motor's amp draw by 1.25 - According to the National Electrical Code (NEC) guidelines, the largest motor's amp draw is increased by 25% to account for the starting current, which is usually higher than the running current.
3. Add the amp draws of the other motors - After adjusting the largest motor's amp draw, add the amp draws of all other motors in the unit.
Given this step-by-step process, the correct calculation involves taking the largest motor's amp draw, multiplying it by 1.25, and then adding the amp draws of all the other motors.
Therefore, the correct answer is:
OB. The largest motor amp draw is multiplied by 1.25 and the other motor amp draws are added to it.
