What is the maximum volt-ampere loading permitted on a 20-ampere branch circuit with a continuous load?

In electrical systems, a branch circuit's capacity must account for continuous loads, which are defined as loads that operate for three hours or more. According to the National Electrical Code (NEC), the maximum loading permitted on a branch circuit must not exceed 80% of its rating when it is servicing a continuous load.

For a 20-ampere branch circuit, the calculation to determine the maximum permitted VA (volt-ampere) loading for continuous usage is as follows:

1. First, calculate the total wattage the circuit can handle:
   [ 20 \text{ amps} \times 120 \text{ volts} = 2400 \text{ watts} ]

2. Now, apply the 80% rule for continuous loads:
   [ 2400 \text{ watts} \times 0.80 = 1920 \text{ watts} ]

Since the calculation of VA is directly related to the wattage in resistive circuits (assuming a power factor of 1), the maximum volt-ampere loading allowed on this branch circuit with a continuous load is 1920 VA.

This is why the correct choice is 1920 VA—it effectively respects the NEC guidelines