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.