Hardware
Installation
9
2.2.2 Single-Phase Three-Wire
This is seen in residential and commercial service with 240 VAC for large appliances. The three wires are
neutral and two line voltage wires with AC waveforms 180° out of phase. The ground wire is not
connected. This results in 120 VAC between either line wire and neutral, or 240 VAC between the two line
wires. Single-phase three-wire circuits can be measured with models WNA-1P-240 or WNA-3Y-208.
Note: Neutral must be connected.
Phase A
LINE
Neutral
Phase B
LOAD
Current
Transformers
WHITE
BLACK
Source
Faces
WHITE
BLACK
120 VAC
120 VAC
240 VAC
Neutral
FT10
WNA-1P-240-FT10
Continental Control Systems
W
ATT
N
ODE
B CT
A CT
Service
B 120 VAC
A 120 VAC
Figure 2.2: Single-Phase Three-Wire Connection