The interruption chamber is the most critical part of circuit breakers. As the operating time grows longer, the problem of the arc chamber is becoming more and more prominent. The traditional detection method is difficult to accurately reflect the state of the interruption chamber. Actually, the measurement of the arc voltage stands in the way for condition assessment of the interruption chamber. Arc voltage measurement is difficult due to the high noise level and presence of a transient recovery voltage. This paper proposes a set up for the online measurement of the arc voltage during circuit breakers operations. In addition, a new method has been proposed to evaluate the condition and to calculate the remaining useful lifetime of the interruption chamber based on the measured arc energy. The setup and the proposed approach are verified experimentally.