Areva MiCOM C232 - 5.6 Connection; 5.6.1 Connecting the Measuring and Auxiliary Circuits

5 Installation and Connection
(continued)
C232-302-401/402/403/404-603 / C232/EN M/A23 5-7
5.6 Connection
The C232 must be connected in accordance with the terminal connection diagram
indicated on the type identification label. The terminal connection diagram is included
among the Supporting Documents supplied with the unit. The terminal connection
diagrams that apply to the C232 are also found in the Appendix to this manual.
Copper leads having a 2.5 mm
2
cross-section are generally suitable as the connecting
leads between the current transformers and the C232. Under certain conditions the
connecting leads between the main current transformers and the C232 must be short
and have a larger cross-section in order to handle the allowable burden on the main
current transformers. Copper leads having a 1.5 mm
2
cross section are adequate for
connecting the binary signal inputs, the output relays and the power supply input.
All connections run into the system must always have a defined potential. Connections
that are pre-wired but not used should preferably be grounded when binary inputs and
output relays are isolated. When binary inputs and output relays are connected to
common potential, the pre-wired but unused connections should be connected to the
common potential of the grouped connections.
5.6.1 Connecting the Measuring and Auxiliary Circuits
Power supply
Before connecting the auxiliary voltage V
A
for the C232 power supply, make sure that
the nominal value of the auxiliary device voltage agrees with the nominal value of the
auxiliary system voltage.
Current-measuring inputs
When connecting the system transformers, check to make sure that the secondary
nominal currents of the system and the unit agree.
The secondary circuit of operating current transformers must not
be opened. If the
secondary circuit of an operating current transformer is opened, there is the danger that
the resulting voltages will endanger people and damage the insulation.
The threaded terminal block for current transformer connection is not
a shorting block.
Therefore always short-circuit the current transformers before loosening the threaded
terminals.