There are four reasons contribute to why a current transformer is burnt and broken:

1)The secondary open circuit of a current transformer, generating high voltage which lead to the current transformer burnt and broken;

2)After working for a long time, current transformer insulation aging, partial breakdown or discharge, generating overvoltage;

3)The contact surface of the current transformer is excessively oxidized while primary connected aluminum, the contact resistance is too higher so that the current transformer is heated;

4)Long time of overload operation by user, the current transformer is overheated.