WattNode Pulse Output kWh Transducer Connection Instructions
Page 5 of 7
The WattNode will correctly measure circuits with a grounded leg, but the measured voltage and power for the phase will be
zero and the status LED will not light for whichever phase is grounded, because the voltage is near zero. If you have a
grounded leg configuration, you can save money by removing the CT for the grounded phase, since all the power will be
measured on the non-grounded phase. We recommend putting the grounded leg (phase) on the
ØB
input and attaching a note
to the WattNode indicating this configuration for future reference.
Three-Phase Four-Wire Wye
This is typically seen in commercial and industrial environments. The wires are neutral and three power lines with AC
waveforms shifted 120° between the successive phases. With this configuration, the line voltage wires may be connected to
the
ØA
,
ØB
,
and
ØC
terminals in any order, so long as the CTs are connected to matching phases. It is important that you
connect
N
(neutral). For these models, the WattNode is powered from the
N
and
ØA
terminals.
Figure 5: Three-Phase Four-Wire Wye Connection
Recommended WattNode Models
The following table shows the WattNode model that should be used, depending on the line to neutral voltage and line to line
voltage (also called phase to phase voltage).
Line to Neutral Voltage
Line to Line Voltage
WattNode Model
120 VAC
208 VAC
WNB-3Y-208-P
Note: you may also use the following delta WattNode models to measure three-phase four-wire wye circuits. The only
difference is that delta WattNode models are powered from
ØA
and
ØB
, rather than
N
and
ØA
. If neutral is present, it must
be connected for accurate measurements.
Line to Neutral Voltage
Line to Line Voltage
WattNode Model
120 - 140 VAC
208 - 240 VAC
WNB-3D-240-P
277 VAC
480 VAC
WNB-3D-480-P
Three-Phase Three-Wire Delta (No Neutral)
This is typically seen in manufacturing and industrial environments. There is no neutral wire, just three power lines with AC
waveforms shifted 120° between the successive phases. With this configuration, the line voltage wires may be connected to
the
ØA
,
ØB
,
and
ØC
terminals in any order, so long as the CTs are connected to matching phases. For these models, the
WattNode is powered from the
ØA
and
ØB
(phase A and phase B) terminals. Note: all delta WattNode models provide a
neutral connection
N
, which allows delta WattNode models to measure both wye and delta configurations.
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