Testing of CT Operated Meters

The subsequent tests should be carried out for CT operated meters:

i) Ratio test through primary injection kit,

ii) Polarity test,

iii) Continuity test of primary and secondary windings,

iv) Insulation resistance test, and

v)  Terminal markings as per name plate details.

It should be remembered that CT Secondary terminals should not be remain open. For CT and PT operated meters, it is preferable to use a Test Terminal Block (TTB). The TTB gives the facilities of shorting CT secondaries for testing reasons without any interruption to the consumer. The CT leads should be directly linked to the meter, although PT supply to the meter should be linked through the fuses of proper rating. For eliminate the possibility of tampering along with the fuses, the fuses should be given with protective cover and properly sealed.