What is the ampacity requirement for a continuous load from a storage type water heater?

The ampacity requirement for a continuous load from a storage-type water heater is set at 125% of the load current. This requirement is outlined in the National Electrical Code (NEC) and is applicable to any load that is expected to operate continuously for three hours or more.

When calculating the ampacity for a continuous load, the code mandates that the circuits are sized to accommodate not just the actual load, but also an additional margin to ensure safety and prevent overheating of conductors. By sizing conductors at 125% of the continuous load, it provides this safety buffer, allowing for operational inefficiencies and ensuring that the electrical infrastructure can handle peak demand without risk.

In the context of a storage-type water heater, which typically draws a substantial amount of current and operates for lengthy periods, adhering to this 125% rule is crucial for both the reliability of the device and the safety of the electrical system overall. Thus, the correct answer reflects the necessity to comply with these safety standards to promote both functionality and compliance with electrical codes.