A lockout device configured to lockout a terminal block. The lockout device includes a pair of sections rotatably coupled to one another in which each of the sections has an upper portion including a corresponding lockout opening and a lower portion for selective reception into the space of an opened terminal block. The sections are rotatable between an opened and closed position. In the opened position, the upper portions are misaligned and the lower portions are aligned to permit at least a portion of the lower portions to be inserted into an opening in an opened terminal block. In the closed position, the lockout openings of the upper portions are aligned to accommodate reception of a lock in the lockout openings to prevent movement away from the closed position and the lower portions are misaligned to prevent removal of the lower portions from the opening in the terminal block.