General purpose branch circuits are 120 volts circuits used for supplying lighting fixtures and receptacle outlets for most small portable appliances. There are usually a number of general purpose branch circuits supplying lights and outlets in different rooms around a residence or commercial or industrial building.

Circuits rated for a maximum of 15 amps using 14 gauge wire were common in older homes but are no longer recommended in new installations. Circuits rated for a maximum of 20 amps using 12 gauge wire are recommended for general purpose branch circuits in modern electrical wiring systems.