A current transformer tester identifies potentially disastrous current transformer faults, preventing the primary current from overwhelming insulation and in effect causing windings to short circuit. With a CT tester, an engineer can construct a comprehensive testing and maintenance plan to address faults before failures occur and expenses ensue. A set of current transformer test instruments will include devices capable of performing saturation testing, which identifies the rated knee point of a signal, and ratio tests via comparing primary and secondary windings when voltage is applied. CT testers help fulfill requirements for IEEE, IEC, and CT standards.