12 Installation
Single-Phase Two-Wire without Neutral
This is seen in residential and commercial service with 208 to 240 Vac for large appliances. The
two conductors have AC waveforms 120° or 180° out of phase. Neutral is not used. For this
configuration, the meter is powered from the
Ø
A
and
Ø
B
(phase A and phase B) terminals.
For best accuracy, we recommend connecting the
N
(neutral) terminal to the ground terminal.
This will not cause ground current to flow because the neutral terminal does not power the meter.
Figure 4: Single-Phase Two-Wire without Neutral Connection
Recommended WattNode Model
This configuration is normally measured with the following WattNode model.
Line-to-Line Voltage
WattNode Model
208 - 240 Vac
WNC-3D-240-MB
If neutral is available, you may also use the WNC-3Y-208-MB model. If you use the
WNC-3Y-208-MB, you will need to hook up the meter as shown in section
and connect neutral. You will need two CTs.
If one of the conductors (phase A or phase B) is grounded, see
below for
recommendations.
Ground
W
HI
TE
B
L
AC
K
Ø
B CT
Ø
C CT
Ø
A CT
Ø
B
Ø
C
N
Ø
A
Common
B+, D1, RxD+/TxD+
E
IA-
4
8
5
PC or Logger
A−, D0, RxD−/TxD−
Continental Control Systems LLC
Status
Status
Status
X
C
B+
A-
M
O
D
B
U
S
Com
WNC
-
WNC
-
W
ATT
N
ODE
®
M
ODBUS
-
MB
-
MB
Phase A
Phase B
WHITE
BLACK
208-240 VAC
LI
N
E
LO
A
D
Shorting
Jumper
Source
Faces
Current
Transformers
3D
-
240
