18 Installation
Connecting Voltage Terminals
Always turn off or disconnect power
before connecting the voltage inputs to the meter. Con-
nect each phase voltage to the appropriate input on the green terminal block; also connect
ground and neutral (if required).
The voltage inputs to the meter do not need to be powered from to the same branch circuit as
the load being monitored. In other words, if you have a three-phase panel with a 100 A three-pole
breaker powering a motor that you wish to monitor, you can power the meter (or several meters)
from a separate 20 A three-pole breaker installed in the same, or even adjacent panel, so long as
the load and voltage connections are supplied from the same electric service.
The green screw terminals handle wire up to 12 AWG (2.5 mm
2
). Strip the wires to expose 1/4” (6
mm) of bare copper. When wiring the meter, do not put more than one wire under a screw. If you
need to distribute power to other meters, use wire nuts or a power distribution block. The section
Electrical Service Types (p. 8)
shows the proper connections for the different meter models
and electrical services.
Verify that the voltage line phases match the CT phases.
If there is any doubt that the meter voltage rating is correct for the circuit being measured, unplug
the green terminal block (to protect the meter), 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:
Figure 1: Front Label Diagram (p. 5)
. After testing, plug in the terminal block, making
sure that is pushed in all the way.
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.
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
Connecting Pulse Outputs
●
The outputs
P1
,
P2
, and
P3
should not be connected to negative voltages (except with
Option SSR
), or to voltages greater than +60 Vdc.
●
The recommended maximum current through the pulse output optoisolators is 5 mA,
although they will generally switch 8-10 mA. If you need to switch higher currents, contact us
about
Option SSR
(solid-state relay); see
-
●
The outputs are isolated (5000 Vac RMS) from dangerous voltages, so you can connect them
with the meter powered. The outputs are also isolated from the meter’s earth ground and
neutral connections.
●
If the output wiring is located near line voltage wiring, use wires or cables rated for the high-
est voltage present, generally 300V or 600V rated wire.
●
If this cable will be in the presence of bare conductors, such as bus-bars, it should be double
insulated or jacketed.
