Installation 19
Connecting Voltage Terminals
Always disconnect power
—by shutting off circuit breakers or removing fuses—before con-
necting the voltage lines to the meter. Connect each voltage input (green terminal block) to the
appropriate phase; also connect ground and neutral (if applicable).
So long as the phase voltages are the same, the meter voltage inputs do not need to be con-
nected to the same branch circuit as the load being monitored. In other words, if you have a
three-phase panel with a 100A three-phase breaker powering a motor that you wish to monitor,
you can power the meter (or several meters) from a separate low current (20 A) three-phase
breaker in the same panel.
When connecting the meter, do not place more than one voltage wire in a screw terminal; use
separate wire nuts or terminal blocks if needed. The screw terminals handle wire up to 12 AWG
(2.5 mm
2
). Prepare the voltage wires by stripping the wires to expose 1/4” (6 mm) of bare wire.
Connect each voltage line to the green terminal block as shown in the section
Electrical Service
Types
.
Verify that the voltage line phases match the CT phases.
After the voltage lines have
been connected, make sure the terminal blocks are securely installed on the meter.
If there is any doubt that the meter voltage rating is correct for the circuit being measured, then
before applying power, unplug the green screw terminal from the meter (so that you do not
damage the meter with excessive voltage), turn on the power, and use a voltmeter to compare the
voltages (probe the terminal block screws) to the values in the white box on the meter front label.
When power is first applied to the meter, check that the LEDs behave normally (see
below): if you see the LEDs flashing red-green-red-green, then
disconnect the power immediately! This indicates the line voltage is too high for this model.
1.0sec
G
R
G
R
G
R
G
R
G
R
G
R
G
R
G
R
G
R
G
R
G
R
G
R
G
R
G
R
G
R
G
R
G
R
G
R
C
B
A
Figure 9: WattNode LED Overvoltage Warning
The WattNode meter is powered from the voltage inputs:
Ø
A
(phase A) to
N
(neutral) for wye
“
-3Y
” models, or
Ø
A
to
Ø
B
for delta “
-3D
” models. If the meter is not receiving at least 80% of the
nominal line voltage, it may stop operating. Since the meter consumes a small amount of power
itself (typically 1-3 watts), you may wish to power the meter from a separate circuit or place the
current transformers downstream of the meter, so its power consumption is not measured
For best accuracy, always connect the
N
(neutral) terminal on the meter. If you are using a delta
meter and the circuit has no neutral, then jumper the earth ground to the
N
(neutral) terminal.
Setting the Modbus Address
Every device on a Modbus network must have a unique address and the correct baud rate. The
WattNode Modbus meter sets the address and baud rate with an eight position DIP switch.
The WattNode meter supports Modbus addresses from 1 to 127 using the DIP switch. Address
0 is used for broadcast messages and is not a valid address. As shipped from the factory, the
meter will be configured with an address of 0, which is invalid and will prevent any communication
and cause the “
Com
” LED to light solid red.
Red
Set the Modbus address by switching DIP switch positions 1-7, each of which adds a different
value to the address. The change will take effect immediately.
