Short answer: current transformer models should be selected by rated voltage, primary current, secondary current, accuracy class, burden, installation type and insulation level.
| LZZBJ9 indoor CT | Common indoor current transformer for medium-voltage switchgear. Confirm ratio, class and mounting dimensions. |
|---|---|
| Outdoor CT | Used for outdoor metering or protection. Confirm insulation level, creepage distance and weather resistance. |
| Protection CT | Selected by protection class, accuracy limit factor and burden. |
| Metering CT | Selected by metering accuracy class, burden and ratio. |
A CT ratio alone is not enough for quotation. Accuracy class, burden and installation type must also be confirmed.