How is the general-purpose lighting load calculated per square foot of area for residential service?

In residential service, the general-purpose lighting load is calculated based on the square footage of the area being served. The National Electrical Code (NEC) provides guidelines for these calculations, which dictate that for general-purpose lighting, a load of 3 volt-amperes per square foot is a commonly accepted standard. This figure allows for an adequate assessment of the electrical needs for lighting in residential spaces, ensuring that circuits can handle the anticipated load while maintaining safety and efficiency.

Using 3 volt-amperes accounts for the typical wattage requirements of standard lighting fixtures found in homes, making it a practical and effective measure for electrical planning and design. This standard is applied universally across residential applications, helping electricians design systems that can accommodate typical usage patterns and lighting types.