What is the method to calculate service for continuous loads based on the load's VA rating?

To calculate service for continuous loads, the correct method involves multiplying the load's VA (volt-ampere) rating by 1.25. This multiplier is used because continuous loads are typically defined as loads that are expected to run for three hours or more. The National Electrical Code (NEC) requires that the service be rated at a level that accounts for potential overloads and ensures safety and efficiency in the electrical system. By applying this 1.25 factor, you ensure that the service can safely accommodate the continuous load without risk of overheating or tripping breakers.

The application of this multiplier also acts as a precautionary measure; it helps to create a buffer that can handle surges or unexpected increases in load, ultimately leading to a more resilient and reliable electrical system.

While other methods such as adding a percentage or dividing by a number may seem reasonable in different contexts, they do not adhere to the specific NEC requirements for continuous loads. Hence, it is essential to follow the conductor sizing and service calculations as outlined in the NEC to ensure proper electrical design and safety standards are met.