Liebert Distribution Monitoring LDM - Manual (Page 16)

Installation
12
4.5 Connecting a Current Transformer to the LIB Board
LIB can monitor eight 5-wire output/subfeed breakers. Two LIB boards are provided to support up to
16 output and/or subfeed breakers. If subfeed breakers are ordered with the unit, the phase CTs are
installed and wired to the LIB. The neutral and ground CTs are also factory-supplied and wired to the
LIB.
Since the CTs must be installed on the subfeed breaker’s neutral and ground cables, they cannot be
installed in the factory. They are located in the bottom of the unit in front of the transformer.
CTs have an arrow, white dot or similar marking that depicts how to position the CT to ensure accu-
rate readings. The arrow, white dot or similar marking must face the load when installing the CT on
the ground and neutral cable. Route the neutral and ground cable through the core of the CTs and
wire-tie the CT to the cable.
If subfeed breakers are installed in the field, up to five CTs may be installed to monitor a subfeed
breaker (three phases, neutral and ground). The neutral and ground CTs may be omitted if monitor-
ing of neutral and ground is not required.
The designators on the LIB are different from those on the PBVI board.
• CT1 (Phase A white wire) begins on TB1 CT1+ and the black wire connects to CT1-.
• The Ground CT for the first subfeed/output circuit breaker connects to TB4 CT35.
Refer to the example below and Tables 3 and 4 for wiring configuration details.
Example: The above pictures show how to install CTs for a subfeed or I-Line output circuit breaker
with neutral and ground being monitoring. The CTs should be wired as follows:
If more output or subfeed CTs need to be installed, continue in the same pattern shown above.
• Connect the Phase A CT for the second breaker on CT5 (white wire to CT5+, black to CT5-).
• Connect the Ground CT for the second breaker to CT36 (white wire to CT36+, black to CT36-).
• Continue the same pattern until all CT connections are used or there are no more output or sub-
feed CTs to add.
First Breaker Second Breaker
CT1+ Phase A CT White wire CT5+ Phase A CT White wire
CT1- Phase A CT Black wire CT5- Phase A CT Black wire
CT2+ Phase B CT White wire CT6+ Phase B CT White wire
CT2- Phase B CT Black wire CT6- Phase B CT Black wire
CT3+ Phase C CT White wire CT7+ Phase C CT White wire
CT3- Phase C CT Black wire CT7- Phase C CT Black wire
CT4+ Neutral CT White wire CT8+ Neutral CT White wire
CT4- Neutral CT Black wire CT8- Neutral CT Black wire
CT35+ Ground CT White wire CT36+ Ground CT White wire
CT35- Ground CT Black wire CT36- Ground CT Black wire
Four CTs
(three phases
and neutral)
Ground CT