What is the minimum unit load used for one-, two-, and multifamily dwellings?

For one-, two-, and multifamily dwellings, the National Electrical Code (NEC) specifies a unit load of 33 volt-amperes per square meter, which is equivalent to 3 volt-amperes per square foot. This standard is established to ensure that electrical systems are adequately designed to handle the expected electrical load of residential buildings.

By using 33 volt-amperes/m2 as the minimum unit load, the NEC aims to provide a balance between safety, capacity, and efficiency in residential electrical installations. This load calculation considers common household appliances and lighting to help ensure that the electrical systems can support everyday use while minimizing the risk of overloading circuits, which can lead to electrical hazards. Therefore, referencing this specific load is critical in both design and installation practices to adhere to safety standards and promote effective energy usage in residential environments.