CT requirement for any application depends on some factors knee-point voltage accuracy-limit factor
64REF can be of Low Impedance type & High Impedance type
1) 64 REF-Low Impedance - Phase CT & Neutral CT can be of different class.For Example : Class X for Neutral CT & Class 5P10 for Phase CT ;
Different Class CT's can be used subject to they should fulfill the values of Knee point voltage & other recommended parameters.
2) 64 REF-High Impedance - CT's of Different Class type should not be used.
64REF can be of Low Impedance type & High Impedance type
1) 64 REF-Low Impedance - Phase CT & Neutral CT can be of different class.For Example : Class X for Neutral CT & Class 5P10 for Phase CT ;
Different Class CT's can be used subject to they should fulfill the values of Knee point voltage & other recommended parameters.
2) 64 REF-High Impedance - CT's of Different Class type should not be used.