REC4 is a 2-pole differential circuit breaker associated with a smart reclosing motor, for safe reclosing of the associated RCCB. A compact unit that is installed as an RCCB, removing the need for interconnections between the motor and the RCCB. Insulation reclosing mode is used to ensure high-sensitivity protection, meaning the unit only recloses when the defect which caused it to trip has disappeared. The unit has a locking system that determines operation in manual or automatic mode (reclosing enabled).