Test Terminal Blocks

Care must be taken that the secondary of a current transformer is not disconnected from its load while current is in the primary, as the transformer secondary will attempt to continue driving current across the effectively infinite impedance up to its core saturation voltage. This may produce a high voltage across the open secondary into the range of several kilovolts, causing arcing, compromising operator and equipment safety, or permanently affecting the accuracy of the transformer.

To avoid personal injury or equipment damage, the secondary must always be short-circuited or connected to a burden.

The solution to this problem is to installation of a Test Terminal Block (TTB) that allows for safe testing, disconnection of the equipment leaving CT’s securly short-circuited.

Using our test/disconnect terminals also reduces possibility of damage to Current Transformers.

Test Terminal Blocks (TTB's) can be used for testing a wide range of electrical equipment including integrating meters and protective relays, without disturbing the normal load circuit. Terminal arrangements can be adapted by us to suit many other applications.

• Front and back connected types.
• All terminals and screws are plated brass.
• Molded insulation barriers between sets of terminals.
• Link facilities for testing purposes.
• Fully complies with BS EN 60947-7-1:2002 (Low voltage switchgear and controlgear)
• Part 7 -1 ancillary equipment - terminal blocks for copper conductors and insulators.
• Working Voltage 415VAC DC
• Rated insulation voltage 2.5kV.
• Rated impulse withstand voltage 6kV.
• Rated cross section 16mm2.
• Rated connecting capacity (mm2) 6, 10, 16.