CT Output

IMO this CT needs to be replaced.

Read what the CT specs are. Like 1000/5 and Max current. As long as the core doesn't saturate you will measure. When this is a continuous load, the CT might get hot and fail. Read about your specific CT and act according the instructions.

Further, if the CT is reading +60%, then the conductor passing through it will also be around +60%, which may mean that it is running hot and ready to fail. If so, then the circuit protective device needs attention for it is not giving the fire prevention function that the facility's insurance company might reasonably expect and in the event of a fire, the Loss Adjuster will visit in an attempt to reduce the insurance company's losses ideally towards zero.

Further, if the CT is transmitting +60%, then the equipment reading the transmitted current is +60% over-range. If so, then the reading will not be accurate, which makes investigating the above paragraph very difficult.

So it's time to stop worrying about the CT in itself and concentrate instead on removing the larger headache, which is that the system is currently well overloaded and ideally requires isolation and de-energising until it has been reconfigured to the point where it can be re-energised safely. For that to take place, hire a qualified local Electrical Engineer.

Rated primary current of Current Transformer is an optimum value of primary current at which, error of the CT are minimum and losses in the CT are also less, that means performance of the CT is best with optimum heating of the transformer. Likewise Rated Secondary Current of Current Transformer is the value of secondary current on which the CT is designed to perform best.

However, there is always some difference in expected value and actual value of output of an instrument transformer in the form of current error and phase angle error in CT, as because primary current of current transformer has to contribute the excitation component of CT core.

Accuracy class of current transformer is the highest permissible percentage composite error at rated current.

Instrument Security Factor (ISF) of current transformer is defined as the ratio of instrument limit primary current to the rated primary current. The instrument limit primary current of metering CT is the value of the primary current beyond which CT core becomes saturated.

For protection current transformer, the ratio of accuracy limit primary current to the rated primary current is called Accuracy Limit Factor (ALF) of current transformer.

If in the design and procurement stage the CT is selected considering the required ISF and ALF there will not be any damage neither to the CT nor the instruments/ relays connected as burden to the CT.

If the RF factor of the CT is 1.5 then the maximum amperage would be 7.5 and the 8 amp output is beyond design specifications.

This condition will not yield incorrect readings and will result in failure of the CT sooner or later.

Not sure why you are experiencing this but apparently the circuit is either overloaded or you have the wrong size CT.

Either way failure is imminent and I suggest you correct the issue(s) before you let all the smoke out of the CT and or the switchgear/metering panel.