Technical requirements for medium voltage class circuit breaker were harmonized by IEC and IEEE, and IEC newly adopted the requirements for class S2 circuit-breaker for overhead-line with the ratings of high-frequency TRV(Transient Recovery Voltage), which IEEE already adopted. Under these circumstances, KERI(Korea Electrotechnology Research Institute) studied testing technologies and facilities, which enable to perform interrupting capacity tests for class S2 circuit-breaker. As results, KERI could carry out interrupting capacity tests for medium voltage class circuit breaker rated up to 3-phase 52[kV] 40[kA], which satisfies the IEC standard.