The circuit closed and the current flows via
the terminal blocks and the plug.
Make Before Break (MBB)– circuits
Throughout cabinet operational life during
assembly verifications, the circuit must be
disconnected allow further operations. For current trasformer assisted
circuits, the other hand paramount importance perform preliminary
shorting prior any circuit opening.
CT
A
N
N
Normal operation circuits
In normal operation, the plug fully inserted.225
3029140000
Application
range
B
9$
Instrument transformer wiring
TTB-Range PUSH connection
.
CT
A
N
N
N
N
CT
A
N
N
CT
A
N
N
CT
A
N
N
CT
A
Voltage circuits not require special operational safety other than avoiding short
circuit the secondary wiring used. Before extraction fully
completed, short circuit established
between its two poles. likewise manner,
the same circuit status can obtained by
bringing the lever into its middle position.
To so, the plug partially extracted
from the terminals.
As result the system allows the operator to
enjoy redundant Make Before Break contact.
Disconnect short circuit circuits
To fully allow consequent operations, the
plug completely extracted from the base
terminals, thus maintaining the previously
established short circuit between its poles and
subsequently opening the circuit. The circuit
can equally safely and completely opened
completing the rotation the lever the left.
B
