Split core current transformers - TCB serie

Split core current transformers - TCB serie

  • Sealable terminals cover included
  • Different characteristics on request
  • Fixing system: to wall, to cable/passing bar or to DIN rail by accessories supplied with the CT (depending by the type)


The short circuit on terminals or the connection to earth can be achieved by the double fast-on or connecting two wires on the same terminal.


The C.T. when used as a current generator for protection relays has electrical characteristics which differ from those of the measuring transformer.

Infact the measuring C.T. is expected to give a saturation of the magnetic circuit with 5P in primary currents while, in the case of protective C.T., it is necessary for the secondary current value to follow the increase in the primary current up to 10-15-20 In, so as to guarantee the intervention of the relay in the case of
unforeseen breakdown current.

It is important not to load the C.T. with a P performance which is greater than that indicated, so as not to modify the saturation value of the C.T.

P=RI2 where:
P= load on the C.T.
R= resistance of the relay + resistance of the cables
I= nominal secondary current of the C.T.


Dual ratio on secondary:
S1-S2 low value, S1-S3 high value