CCS WattNode WND-WR-MB, Installation Manual

Page: 6 / 16

Page 6 of 16 WND-WR-MB-Inst-1.03
2.2.5 Three-Phase, Four-Wire Wye
This is a common commercial and industrial service that includes a neutral conductor. The CTs
should be placed around the L1, L2 and L3 line conductors and connected to the
CT1 , CT2 , and
CT3 terminals respectively. The meter will be powered from the V
N
, V
A
, and V
B
terminals.
V
B
V
C
V
N
V
A
W
ATT
N
ODE ®
CT2 CT1 CT3
L3
L2
L1
Neutral
Earth
Figure 6: Three-Phase Four-Wire Wye with Neutral
2.2.6 Grounded Leg Service
In rare cases with delta services or single-phase two-wire, line-to-line services, one of the phases
may be grounded.
The meter will correctly measure services with a grounded leg, but the measured voltage and power
for the grounded phase will be zero. The status LEDs will not light for the grounded phase because
the voltage is near zero. This type of service may result in unusual power factors.
See the web article Corner-Grounded Delta Circuits for more information.
2.2.7 Four-Wire Delta Service
There are several names for this service type including “high-leg”, “wild-leg”, “stinger leg”, or “wild
phase”. This is a three-phase delta service with a center-tap on one of the transformer windings
to create a neutral for single-phase loads. These occur in North America in two configurations:
120/208/240 Vac and 240/415/480 Vac.
With the WattNode Wide-Range meter, this service type can be measured just like any three-phase,
four-wire wye service (
Figure 6 ) using three CTs. By convention, you should connect the V
B
terminal
to the high leg. See Four-Wire Delta Circuits for more information.
3 Installation
3.1 Installation Checklist
See the sections referenced below for installation details.
□
Turn off power before making line voltage connections.
□
Mount the meter (see 3.2 ).
□
Connect circuit breakers or fuses and disconnects (see 3.3.1 ).
□
Connect the line voltage wires to the meter’s green terminal block (see 3.3.2 ).
□
Mount the CTs around the line conductors. Make sure the CTs face the source (see 3.4 ).
□
Connect the twisted white and black wires from the CTs to the black terminal block on the
meter, matching the wire colors to the white and black dots on the meter label (see
3.4.2 ).
□
Check that the CT phases match the line voltage phases: CT1 with V
A
, CT2 with V
B
, and CT3
with V
C
, unless you have specially configured the ConnectionType or MeterConfig registers
(see 3.4 ).
□
Record the CT rated current for each CT. They will be required during commissioning.
□
Connect the output terminals of the meter to the monitoring equipment (see 3.5 ).
□
Check that all the wires are securely installed in the terminal blocks by tugging on each wire.
□
Turn on power to the meter.
□
Verify that the LEDs indicate correct operation (see 4.2 , 4.3 ).