Abstract Solid‐state circuit breakers (SSCBs) are designed to interrupt fault currents typically several orders faster than its electromechanical counterparts. However, such an ultrafast switching operation would produce a dangerous overvoltage which might cause damages to SSCBs and other circuit elements in the system. This paper proposes a novel snubber circuit for suppressing the overvoltage. It takes the advantages of both resistor‐capacitor‐diode (RCD) snubbers and metal oxide varistors (MOVs). Its operating process is analysed before the proposed snubber circuit for 400V DC SSCBs is designed. Pspice simulator is employed for simulating the operating process and a prototype SSCB with the proposed snubber is built and tested in a lab‐scale DC system. The results of simulation and experiment validate the effectiveness of the proposed snubber.