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Making the electrical connection Chapter 5
Installing the IED
Table 5: Designations for 1/1 x 19” casing with 2 TRM slots
4.1 Configuration for analog CT inputs
The secondary rated current of the CT (i.e. 1A or 5A) determines the choice of TRM in the IED.
Two TRMs are available, One is dimensioned for an input current of 5A and the other for an
input of 1A. If the CT rated secondary current does not match the TRM input current rating ad-
justments can be made in settings depending on the tolerance of the TRM.
4.2 Connecting to CT and VT circuits
CTs and VTs are connected to the TRM connection terminal on the rear-side of the IED.
Use a solid conductor with a cross section area between 2.5-6 mm
2
(AWG14-12) or a stranded
conductor with a cross section area between 2.5-4 mm
2
.
If the IED is equipped with a test-switch of type RTXP 24 COMBIFLEX wires with 20 A sock-
ets must be used to connect the CT and VT circuits.
Connectors X401 and X402 for current and voltage transformer circuits are so called
“feed-through IED blocks” and are designed for conductors with cross sectional area up to 4
mm
2
(AWG 12). The screws used to fasten the conductors should be tightened with a torque of
1Nm.
Module Rear Positions
PSM X11
BIM, BOM or
IOM
X31 and X32 etc. to X131 and
X132
MIM X31, X41, etc. or X131
GSM X131
SLM X301:A, B, C, D
LDCM X302:A, B
LDCM X303:A, B
OEM X311:A, B, C, D
LDCM X312:A, B
LDCM X313:A, B
TRM 1 X401
TRM 2 X411
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