Final answer:
The minimum ampacity for the 120/240-volt, 3-wire service conductors of a one-family dwelling with a 9.5 kVA load is 40 amps, after rounding up the precise calculation of 39.58 amps.
Step-by-step explanation:
The minimum ampacity for the service conductors can be calculated by taking the initial net computed load and considering the appropriate voltage level and necessary de-rating factors. Given an initial net load of 9.5 kVA for a 120/240-volt service, the calculation for the minimum ampacity (I) is done using the formula I = Power (P) / Voltage (V). In this case, the calculation is straightforward because 9.5 kVA is equivalent to 9500 VA (since 1 kVA = 1000 VA), and for a 120/240-volt system, we use the 240-volt value to calculate the ampacity.
To find the ampacity, divide the total VA by the voltage level:
I = 9500 VA / 240 V
= 39.58 Amps.
Therefore, you would need to round up to the next standard conductor size, which means the minimum amperage for the service conductors would be 40 amps.