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

When determining the maximum volt-ampere (VA) loading allowed on a branch circuit with a continuous load, it is important to consider the National Electrical Code (NEC) requirements. A continuous load is defined as a load where the maximum current is expected to continue for three hours or more.

For a 20-ampere branch circuit, the NEC specifies that you should not load the circuit to more than 80% of its maximum capacity for continuous loads. The maximum capacity of a 20-ampere circuit at 120 volts (the typical voltage used in residential wiring) can be calculated as follows:

• Maximum capacity = Current (amperes) × Voltage (volts)

• Maximum capacity = 20 A × 120 V = 2400 VA

Now, applying the 80% rule for continuous loads:

• Allowable continuous load = Maximum capacity × 80%

• Allowable continuous load = 2400 VA × 0.8 = 1920 VA

Therefore, the maximum VA loading allowed on a 20-ampere branch circuit with a continuous load is 1920 VA, making it the correct answer. Understanding and applying this rule is crucial for ensuring safety and compliance with electrical codes in