why C.T secondary are rated 5A generally?

Answer Posted / ashim kumar das

Its basically depends on the circuitry, whether you are
using it as a metering CT or a Protection CT.
For metering purpose generally 5A CT is used, because the
VA drop occurd in the cable between CT and the metering
instrument doesn't much harmfull for the system.

But for protection purpose 1A CT is recommended, because if
the distance between the CT and the protection relay is
very large, the VA drop occurd in the cable can give
reduced current reading to the instrument and this will be
a thread to the machine.

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