This study performed test on the temperature characteristics and short-time current performance of a Plug-In MCCB developed for rapid replacement of an MCCB. A temperature rise test for the developed Plug-In MCCB showed that the maximum temperature rise was 13.7℃. The temperature rise analysis performed after the short-time current performance and mechanical operation tests found that the maximum temperature rise was 18.5℃ and that all parts were safe. After the short-time current performance test was performed under conditions of a test voltage of 2.5 kV and a test period of a time of 60 seconds for the neutral wire, the Plug-In MCCB was fond to be in a good state. This study performed the tests on the developed Plug-In MCCB by inserting into, and taking out of, a bus bar 1,000 times and found that the Plug-In MCCB experienced no physical deformation and showed good electrical characteristics. The evaluation on the insulation performance of the developed Plug-In MCCB between the circuit and ground and between the phases found that the insulation resistance was more than 500 MΩ. In addition, the result of the structural test on the Plug-In MCCB showed that it satisfied all related requirements.