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8
4.2 Installing a Solid-Core Current Transformer
The CT for the panelboard main input circuit breaker is hard-wired to the connectors. Removing CT
wires from the connector requires a pin extraction tool. Contact Liebert Services at 1-800-LIEBERT
(1-800-543-2378) for assistance.
Typically the three-phase and neutral wires utilize a CT rating of 100:1, 200:1 or 500:1, while the
ground wire utilizes a CT rating of 100:1.
Route the circuit wire through the core of the CT and wire-tie the CT to the cable. Refer to the manu-
facturer’s documentation for proper orientation to ensure accurate readings. Generally, CTs have an
arrow, white dot or similar marking to indicate how to position the CT.
For the Liebert LDM, CTs have a white dot that must face the source on the three-phase wires and
must face the load on the neutral and ground wires.
!
WARNING
A solid-core CT cannot be installed on a wire while current is flowing through the wire.
Damage to burden resistor and CT will occur. Power needs to be removed prior to installing
and/or removing any CT. CTs should be installed by qualified electricians only.
NOTE
When replacing or installing a CT, ensure the replacement CT has a secondary rating of 1A—
for example, 100:1, 200:1 or 500:1. Using a higher-rated CT—for example, 100:5 or 500:5—will
damage the burden resistors on the PBVI board.
NOTE
When installing CTs for a large branch circuit breaker or subfeed, verify which monitoring
board is installed.
• A PBVI board can support one subfeed per panelboard (if neutral and ground will be
monitored) or up to three subfeeds if neutral and ground are not monitored.
• One LIB can support up to eight output and/or subfeed breakers.
• Two LIB boards are provided to support up to 16 output and/or subfeed breakers.