What is the required branch circuit ampacity of a water heater with a nameplate rating of 7,200VA at 240V?

To determine the required branch circuit ampacity for the water heater, you start with the nameplate rating of 7,200 VA and the operating voltage of 240 V. The first step is to calculate the current (amperage) using the formula:

Current (I) = Power (VA) / Voltage (V)

By substituting the given values into the equation, you have:

I = 7,200 VA / 240 V

I = 30 A

This value, 30 A, represents the load on the circuit. However, when selecting the proper ampacity for a branch circuit in residential applications, it is crucial to consider the continuous load aspect. The National Electrical Code (NEC) recommends that circuits serving continuous loads (which are loads that run for three hours or more) be rated for at least 125% of the regular load calculation.

125% of 30 A is:

30 A × 1.25 = 37.5 A

This additional capacity ensures that the circuit can handle the continuous load safely without overheating. Therefore, the required branch circuit ampacity for the water heater would be 37.5 A, which corresponds to the choice noted. This calculation is essential in ensuring safe