A typical home has several circuits to deliver electricity to different areas of the property.
The circuits that deliver electricity to the various areas of a home are referred to as branch circuits. They originate at a service distribution panel, which has two hot bus bars and one neutral bus bar.
Depending on the amount of electricity a given circuit needs to deliver, it may attach to only one hot bus bar and the neutral bus bar or to both hot bus bars. For example, a circuit that delivers 120 volts connects to one hot bus bar and the neutral bus bar, while a circuit that delivers 240 volts connects to both hot bus bars.
The means of attachment is commonly known as a fuse or circuit breaker, and it protects the circuit from sudden surges in current. Neutral conductors are all grounded through direct contact with the soil. Unlike the hot bus bars, a neutral bus bar does not have an over-current protection device so it can maintain 0 volts at all times.