278 Electrical Power Systems Technology
Branch Circuit Wiring
A branch circuit usually consists of a nonmetallic-sheathed cable that is
connected into a power distribution panel. Each branch circuit that is wired
from the power distribution panel is protected by a fuse or circuit breaker.
The power panel also has a main switch that controls all of the branch cir-
cuits that are connected to it.
Single-phase Branch Circuits
A diagram of a single-phase three-wire (120/240-volt) power distribu-
tion panel is shown in Figure 10-8. Notice that eight 120-volt branch cir-
cuits and one 240-volt circuit are available from the power panel. This type
of system is used in most homes, where several 120-volt branch circuits
and, typically, three or four 240-volt branch circuits are required. Notice in
Figure 10-8 that each hot line has a circuit breaker, while the neutral line
Figure 10-8. Diagram of a power distribution panel for a single-phase, three-
wire branch