According to NEC Table 220.12, what is the minimum general lighting load for office buildings based on?

The minimum general lighting load for office buildings, as specified in NEC Table 220.12, is based on the requirement for ensuring adequate illumination for various types of spaces. For office buildings, the NEC standard prescribes a value of 3-1/2 VA/ft². This determination considers the typical lighting needs in office environments where proper visibility is crucial for productivity and safety.

By establishing this minimum standard, the NEC aims to assure that office spaces are sufficiently illuminated to meet both functional and comfort levels for employees. The chosen value takes into account the variety of activities that occupants engage in, from reading and writing to working on computers, necessitating a higher lighting load than what might be appropriate for other less demanding spaces.

This specification reflects the NEC's commitment to maintaining safety and promoting efficient energy use while ensuring that lighting is adequate for the intended purpose within office settings.