What is the maximum allowable voltage for a branch circuit supplying lighting fixtures in a residence?

The maximum allowable voltage for a branch circuit supplying lighting fixtures in a residence is 120 volts. This standard is primarily based on safety and practicality, as 120 volts is sufficient to power typical household lighting while reducing the risk of electrocution and ensuring compatibility with common fixtures, lamps, and bulbs used in residential settings.

Branch circuits for lighting in residences are designed to operate at this voltage level to ensure that homeowners can safely operate their lighting without the increased hazards associated with higher voltages. Other voltage options, such as 240 volts or beyond, are generally reserved for specific high-demand appliances and equipment rather than standard lighting applications.

This adherence to the 120-volt standard is also reinforced by the National Electrical Code (NEC), which governs electrical standards and practices, thereby ensuring consistency and safety in residential electrical systems.